This document discusses cancer development and genetics. It notes that cancer develops through multiple genetic lesions over time, affecting genes like tumor suppressors and proto-oncogenes. Two key tumor suppressor genes discussed are retinoblastoma (Rb) and p53. For Rb, mutations can cause either familial or sporadic retinoblastoma depending on whether one or both alleles are mutated. Both forms require inactivation of both alleles. p53 is often mutated in many cancer types and can be inactivated via dominant negative mutations. The Rb and p53 proteins normally function in pathways that regulate the cell cycle and prevent uncontrolled growth.

1. 1
Multistep nature of cancer development
• Phenotypic progression
– loss of control over cell growth/death (neoplasm)
– invasiveness (carcinoma)
– distal spread (metastatic tumor)
• Genetic progression
– multiple genetic lesions required for cancer
– normal cell malignant cell
– how many independent genetic lesions are necessary for
development of a clinically obvious cancer?
– mutation rates, rate-limiting steps, genomic instability
Cancer genes
• What genes, when altered, promote cancer?
– tumor suppressor genes and proto-oncogenes
• Some genes are altered in a restricted set of tumor types
– e.g., APC in colorectal carcinoma
• Others are altered in a broad spectrum of tumor types
– e.g., p53 and the Ras genes
• The importance of tumor gene “pathways”
– the p53 and Rb tumor suppressor pathways
Proto-oncogenes vs. tumor suppressor genes
Proto-oncogenes promote cancer when
malignantly activated
– An activated proto-oncogene contributes to
tumorigenesis by "gain-of-function"
– Thus, an activated proto-oncogene is genetically
dominant at the cellular level
• an activated oncogene can elicit a new phenotype
(tumorigenesis) even in the presence of the corresponding
wildtype allele
Proto-oncogenes vs. tumor suppressor genes
Tumor suppressor genes promote cancer when
malignantly inactivated
– A tumor suppressor contributes to tumorigenesis by
"loss-of-function"
– In most instances, an inactivated tumor suppressor
gene is genetically recessive at the cellular level.
• it will not promote tumorigenesis in diploid cells unless
the other (wildtype) allele is also lost or inactivated
• some exceptions (e.g., dominant-negative p53 mutations)
Tumor suppressor genes
• in this lecture we will focus on…
– the retinoblastoma susceptibility (Rb) gene
– the p53 tumor suppressor gene
• genetic properties
• biochemical functions of their protein products
• the p53 and Rb tumor suppressor “pathways”
Cancer susceptibility syndromes
• What proportion of human cancers are heritable?
• Hereditary syndromes of cancer susceptibility are
usually caused by germline mutations of tumor
suppressor genes.
– familial retinoblastoma: Rb
– Li-Fraumeni syndrome: p53
– familial adenomatous polyposis coli: APC
– hereditary non-adenomatous c.c.: MLH1, MSH2
• Penetrance: fully penetrant mutations segregate as
dominant traits in a Mendelian fashion

2. 2
Sporadic and Heritable forms
of Retinoblastoma
• age of tumor onset
– sporadic (~60% of cases): ~ 6 years
– heritable (~40% “ “ ): ~ 2 years
• number of independent tumors
– sporadic: single tumor (only one eye is affected)
– heritable: multiple tumors (both eyes are affected)
• tumor frequencies in children of patients
– sporadic: 1 in 105
– heritable: 1 in 2
patients with heritable retinoblastoma transmit
a “Rb susceptibility gene” to their children in a
dominant Mendelian fashion
Knudson's hypothesis (1970s)
• Two (rate-limiting) genetic lesions required…
• Sporadic retinoblastoma:
– both alterations are acquired somatically
– incidence: (10-6)(10-6)(107 cells) = 10-5 tumors/person
– very rare; involves only one eye
• Heritable retinoblastoma:
– one alteration is inherited in the germline
(i.e., the “Rb susceptibility gene”)
– the second alteration is acquired somatically
– incidence: (1)(10-6)(107 cells) = 10 tumors/person
– all carriers affected; involves both eyes!!
– one mutation is inherited in the germline
– second mutation is acquired somatically
– incidence: (1)(10-6)(107 cells) = 10 tumors/person
• All mutation carriers are affected
– Rb susceptibility is a highly penetrant trait
– tumor susceptibility is transmitted as a dominant trait in family
pedigrees (despite the fact that tumor suppression genes
function recessively at the cellular level).
Hereditary Retinoblastoma
The Retinoblastoma (Rb) gene
• What are the two rate-limiting genetic alterations?
• Cytogenetic abnormalities of chromosome 13:
– interstitial deletions of variable length
– always involve material from chromosome band 13q14
– sporadic patients: deletions in tumor cells only
– heritable patients: deletions in both normal & tumor cells
• Is Rb susceptibility due to genetic loss at 13q14?
If so, then the two mutations required for retinoblastoma might
represent inactivation of both alleles of a single gene at 13q14
Sporadic
Retinoblastoma
Familial
Retinoblastoma
tumor cells:
Rb, Rb
(normal)
Rbm1, Rb
(normal)
Rbm1, Rbm2
(neoplastic)
Rbm1, Rbm2
(neoplastic)
m1
m2
m2
malignant mutations of the Rb gene act recessively at the
cellular level, contributing to neoplasia by loss-of-function
retinal cells:
The Retinoblastoma gene (Rb)
• 1988: isolation of the Rb gene on 13q14
Familial retinoblastoma
• one Rb gene lesion in germline of familial patients
• other (normal) Rb allele lost or inactivated in tumors
Sporadic retinoblastoma
• both alleles of Rb are normal in germline
• both Rb alleles lost or inactivated in tumors
Important: genetic lesions in the same gene are
responsible for both the familial and sporadic forms
of retinoblastoma!!

3. 3
chromosome 13
maternal
&
paternal
homologues
Inactivation of the second Rb allele (in somatic cells)
Rbm1
Rbm1 Rbm2
de novo
mutation
Rbm1
chromosome
loss
Rbm1 Rbm1
chromosome
loss
&
reduplication
gene
conversionRbm1 Rbm1
The penetrance of
germline Rb mutations
• Almost all carriers will develop retinoblastoma
– high penetrance
• (mutation rate)(target cells) = (10-6)(107 cells) = 10
• retinoblastoma susceptibility is transmitted as a
dominant Mendelian trait
• Some carriers will also develop osteosarcoma
– low penetrance
• (mutation rate)(target cells) < 1
• osteosarcoma susceptibility is not transmitted as a
dominant Mendelian trait
Tumor Suppressors: the p53 gene
• p53 encodes a transcription factor
• the p53 gene is altered in many human tumors (usually by
missense mutation).
• in vitro cell transformation by mutant p53 genes.
Is p53 a proto-oncogene?
• murine erythroleukemias induced by Friend Leukemia Virus:
a natural knockout of the p53 gene by proviral insertion!
• suppression of cell transformation by the wild-type p53 gene.
Is p53 a tumor suppressor gene?
Dominant-negative mutations
of a tumor suppressor gene
• dominant-positive mutation (e.g., missense
mutations in the Ras proto-oncogenes).
• recessive-negative mutation (e.g., Rb loss).
• dominant-negative mutation (e.g., many p53
missense mutations).
• note: dominant-negative mutations result in
functional inactivation of the protein products of
both alleles (including the normal allele).
Dominant-negative mutations of p53
• how do dominant-negative mutations work?
• p53 normally functions as a homo-tetramer
• consider p53 function in a cell with one wildtype
and one mutant p53 allele:
functional
p53 tetramer?
yes
yes
no
no
wildtype p53
mutant p53
Dominant-negative mutations of p53
• how do dominant-negative mutations work?
• p53 normally functions as a homo-tetramer
• consider p53 function in a cell with one wildtype
and one mutant p53 allele:
functional
p53 tetramer?
yes
yes
no
no
wildtype p53
mutant p53
• mutant p53 is more
stable than wildtype p53

4. 4
p53 mutations in
hereditary and sporadic cancer
• Li-Fraumeni Syndrome (LFS)
– caused by germline mutations of p53
– LFS carriers develop many different forms
of cancer
• sporadic cancer
– often caused by somatic mutations of p53
– very common in human cancer
– found in many different forms of cancer
Tumor suppressor proteins
• proteins encoded by Rb and p53
• the normal functions of these proteins
• mechanisms of tumor suppression
• the Rb and p53 tumor suppressor pathways
Phosphorylation of the Rb protein
• The phosphorylation state of Rb changes during
normal cell cycle progression.
– Rb is hypophosphorylated in:
• G0 (resting cells)
• early G1 (cycling cells)
– Rb is hyperphosphorylated in:
• S phase
• G2 phase
– Rb is phosphorylated before the G1/S transition…
• by an enzymatic complex: CDK4 / cyclin D
M
G1 S
G2
restriction
point
G0
(resting cell)
cell cycle progression
Rb Rb~P
Cdk4 / cyclin D
The restriction point (in late G1)
• the major control point of cell cycle progression
• G1/S transition is mediated by the E2F family of
transcription factors
• E2F binds the promoters of genes required for cell
cycle progression (G1/S transition and S phase).
E2F
promoter of
S-phase genes
transcription
Some S phase genes regulated by E2F:
S phase gene Function
• thymidine kinase nucleotide synthesis
• DHFR (dihydrofolate reductase) “ “
• DNA polymerase α DNA synthesis
• ORC1 “ “
• histone H2A chromosome assembly
• cyclin E cell cycle progression
• cyclin A “ “ “

5. 5
Resting cells and early G1 phase cells
• hypophosphorylated Rb binds promoter-bound E2F
• Rb inactivates transcription by E2F
• S phase genes are repressed
• G1/S transition is blocked
Rb
E2F
S-phase genes
repressed
restriction point
• CDK4/cyclin D phosphorylates Rb in the “pocket”
• hyperphosphorylated Rb dissociates from E2F
• E2F activates transcription of S phase genes
• cells enter S phase
Rb
P P P
E2F
Rb
S-phase genes
activated
E2F
S-phase genes
repressed
Cdk4/cyclin D
• In normal cells, phosphorylation of Rb by the
CDK4/cyclin D kinase is a highly regulated
• Focal point for the major signal transduction
pathways that control normal cell growth
Rb
P P P
E2F
Rb
S-phase genes
activated
E2F
S-phase genes
repressed
Cdk4/cyclin D
Rb
P P P
E2F
Rb
S-phase genes
activated
E2F
S-phase genes
repressed
Cdk4/cyclin D
diverse signaling pathways
The function of Rb
• hypophosphorylated Rb serves to restrain the
proliferation of normal cells.
• regulated phosphorylation of Rb allows normal
cells to proliferate at the correct time and place.
• therefore, imagine the consequences of losing
normal Rb function…
– deregulation of E2F (and the G1/S transition)!
• how might Rb become inactivated in cancer?
Inactivation of Rb function in tumors
(leaving E2F unregulated)
• Direct inactivation:
– Rb gene deletion (occurs in retinoblastoma)
– point mutations in the Rb pocket (in retinoblastoma)
– occupancy of the Rb pocket by early proteins of
DNA tumor viruses
• human papilloma virus (HPV), an etiological agent in
human cervical carcinomas
• HPV encodes two proteins required for tumorigenesis
• E7 binds the pocket of hypophosphorylated Rb
• Deregulation of E2F (and the G1/S transition)

6. 6
The Rb tumor suppressor pathway
p16
Rb
P P P
E2F
Rb
S-phase genes
activated
E2F
S-phase genes
repressed
Cdk4 / cyclin D
Indirect inactivation of Rb function in tumors
• overexpression of cyclin D1
– breast cancer, B cell lymphoma
• loss of p16, an inhibitor of Cdk4
– many human cancers
• inherited point mutation in Cdk4 that renders it
insensitive to inhibition by p16
– familial melanoma
»Inactivation of the Rb pathway occurs in most, if not
all, human tumors!
Normal functions of the p53 protein
• p53 polypeptides are very unstable in normal cells
(1/2 life of ~30 minutes)
• the cellular response to genotoxic stress
– DNA damage by UV light, ionizing radiation, chemical
carcinogens, errors in replication, etc.)
– induction of certain signal transduction pathways
• post-translational modifications of p53 polypeptides:
– especially, phosphorylation and acetylation
– stabilize p53 (1/2 life of ~150 min.), leading to higher
steady-state levels
– increase the transcriptional activity of p53
consequences of p53 activation
• The transcriptional activity of p53 induces a
cellular response, the nature of which is dependent
on various factors, including the cell type.
– p53 induces G1 arrest (and DNA repair) in:
• normal fibroblasts
• certain epithelial cells
– p53 induces apoptosis in:
• thymocytes
p53 induction of
cell cycle arrest or apoptosis
• in either case, replication of damaged DNA ceases
• prevents accumulation of oncogenic mutations
• In essence, p53 suppresses tumor formation by
maintaining the integrity of the genetic material in
cells subjected to genotoxic stress.
Transcriptional targets of p53
• p21 CDK inhibitor
G1 and G2 arrest in fibroblasts
• 14-3-3σ
G2 arrest in epithelial cells
• PUMA
promotes apoptosis in thymocytes, fibroblasts, neurons
• p53R2 nuclear ribonucleotide reductase
required for DNA repair
• p48 subunit of the XPA complex
required for nucleotide excision repair
• etc…

7. 7
Normal cell p53 mutant cell
p53 protein is activated
p53 induces target genes
DNA repair
growth arrest
Apoptosis
No response
DNA damage
persists
- proto-oncogenes activated
- tumor suppressors inactivated
- cancer -
Normal cell
genotoxic stress
The p53 tumor suppressor pathway
p53
mdm2
p21
ATM
»Inactivation of the p53 pathway occurs in most,
if not all, human tumors!
Sporadic colorectal carcinoma
• Accounts for >80% of colorectal carcinomas.
• Natural history of the sporadic disease
(viewed by colonoscopy):
– normal epithelium
– hyperproliferative epithelium (APC*)
– early adenoma (APC*)
– intermediate adenoma (APC*, Ras*)
– late adenoma (APC*, Ras*, SMAD2/4*)
– carcinoma (APC*, Ras*, SMAD2/4*, p53*)
– metastasis
Hereditary colorectal carcinoma
• A predisposition to colorectal carcinoma is
associated with two distinct syndromes.
– Familial adenomatous polyposis coli
(FAP)
– Heritable non-polyposis colorectal carcinoma
(HNPCC)
Familial adenomatous polyposis coli (FAP)
• FAP: rare, autosomal, dominantly-inherited
• Natural history of FAP:
– multiple polyps (hundreds or thousands) develop
throughout the colon by early adulthood.
– inevitably, one or more of these polyps will progress into
an invasive carcinoma.
• FAP results from inherited lesions in the APC gene
(which behaves as conventional tumor suppressor)
• FAP accounts for less than 1% of all colorectal
carcinomas. However, most sporadic cases of
colorectal carcinoma have somatic mutations of APC.

8. 8
Hereditary non-polyposis colorectal carcinoma
(HNPCC).
• HNPCC: autosomal, dominantly-inherited
• Natural history of HNPCC:
– Carriers do not have an obvious pre-malignant condition
(e.g., the histology of their colon is normal).
– Carriers are predisposed to develop colorectal carcinoma.
• HNPCC results from inherited lesions in genes
encoding components of the DNA mismatch repair
system:
– hMSH2, hMLH1, hPMS1, or hPMS2
Mismatch repair defects in HNPCC
• mismatch repair incorrectly paired nucleotides
• malignant cells of HNPCC tumors exhibit genetic
instability at the nucleotide level
• this underlying genetic instability accelerates
malignant progression.
• HNPCC accounts for 2-4% of colorectal carcinomas
• In addition, ~13% of sporadic colorectal carcinomas
display mismatch repair deficiency; these all harbor
somatic mutations in one of the mismatch repair genes
implicated in HNPCC
Tumor Suppression
• tumor suppressors inhibit tumor formation by a
variety of different mechanisms:
• negative control of cell growth...
– by regulating cell cycle progression (e.g., Rb, p16)
– by regulating signal transduction pathways (APC)
• maintenance of genomic integrity...
– by regulating the cellular response to DNA damage
(p53, ATM, Chk2)
– by functioning as effectors of DNA repair
(hMSH2, hMLH1)
.
• Linkage analysis of family pedigrees: identify
polymorphic markers that co-segregate with tumor
susceptibility
• Loss of heterozygosity (LOH) in tumor cells:
identify polymorphic markers that exhibit tumor-
specific LOH
Positional cloning: search for transcription units
(candidate genes) and analyze each for:
– germline mutations that co-segregate with tumor
susceptibility (in familial tumors)
– somatic mutations that arise uniquely in the malignant
cells (in sporadic tumors).
Methods to isolate tumor suppressor genes

9. 9
Chromosome 13
maternal
&
paternal
homologues
the second Rb mutation (in somatic cells)
Rbm1
Rbm1 Rbm2
de novo
mutation
Rbm1
chromosome
loss
Rbm1 Rbm1
chromosome
loss
&
reduplication
gene
conversionRbm1 Rbm1
LOH
LOH
LOH

11.  World Cancer Day – 4th February 2014
 By 2025, there will be more than 20 million
new cancer cases per year, compared with
14.1 million in 2012,
IARCWorld Cancer Report 2014

12.  Greek word : Karkinos (crab)
 Hippocrates : First coined the term
 Cancer is an overgrowth of cells bearing
cumulative genetic injuries that confer
growth advantage over the normal cells

14.  Accumulation of mutations and epigenomic
changes in somatic cells

15. Sporadic
Familial
Hereditary
77-80%
10-15 %
5-10%
Nagy R, Sweet K, EngC. Highly penetrant hereditary cancer syndromes. Oncogene. 2004 Aug 23;23(38):6445-70

16. • Early onset
• Bilateral/Multifocal
Disease
• Multiple Primary
cancer in single
individual
• Clusters of Cancer in
family
• Rare cancers
• Precursor lesions

18. Deregulating Cellular
Energetic
Avoiding immune
Destruction
Hanahan D, Weinberg RA. The hallmarks of cancer. Cell. 2000

19.  Gene : A hereditary unit consisting of a sequence of
DNA that occupies a specific location on a
chromosome and determines a particular
characteristic in an organism
 Trait : A distinguishing feature, a genetically
determined characteristic or condition.
 Locus : specific area on chromosome where the gene
is found
 Allele :Versions of a gene
 Genotype : the genetic makeup of an organism
 Phenotype : the physical appearance of an organism
 Pleiotropy : the ability of a gene to affect an
organism in many ways

20.  Penetrance
 The probability that a gene will have any
phenotypic expression
 Its an all or none concept
 Expressivity
 Severity of the manifestations of the phenotype

21. Driver Mutation :
• Contribute to
Oncogenesis
• Provide growth
advantages
• Occurs in
• Oncogenes
• Tumor SuppressorGenes
Passenger
Mutation :
• Neutral Mutation
• Carried along the
ride
• Does not cause or
propel cancer’s
growth or spread

22.  Proto-oncogenes – normally promote
normal cell growth; mutations convert them
to oncogenes.
 Tumor suppressor genes – normally restrain
cell growth; loss of function results in
unregulated growth.

23.  Oncogenes
 promote cell
proliferation
 dominant & highly
conserved
 types :
▪ viral oncogenes [ v-
oncs ]
▪ cellular oncogenes [ c-
oncs ]

24. Secreted Growth Factors
• c-sis, hst
Cell Surface Receptors
• c-sis, hst erb B, ret, trk, fes, fms
IntracellularTransducers
• c-src, c-abl, mst, ras
DNA-binding Nuclear Proteins
• myc, jun, fos
Regulators of the Cell Cycle
• bcl, bax, bad

26.  Tumor Suppressor Gene
 Inhibits growth and multiplication of mutated
cells
 Prevent neoplastic transformation
 Recessive and highly conserved
 Categories :
 Caretaker Gene
 Gatekeeper Gene

27. Category Gene Function Tumors
Gatekeeper p53 Transcription factor Li-Fraumeni
syndrome
Rb1 Transcriptional
regulator
Familial
retinoblastoma
APC Regulates β-
catenin function
Familial
Adenomatus
polyposis
Caretaker BRCA1 DNA repair Breast and ovarian
cancer
BRCA2 DNA repair Breast Cancer
MSH2 DNA mismatch
repair
HNPCC

37. Syndrome Incidence Genes
Involve
d
Molecular Pathway
affected
RenalType Others
characteristics
VHL 1:36,000 VHL Hypoxic
pathway(through
HIF)
Clear cell
RCC
pancreatic cysts
and
neuroendocrine
tumors,
pheochromocyto
ma,
retina I angiomas,
hemangioblastom
as
Birt-
Hogg-
Dube
rare FLCN m-TOR Variable
subtypes
cutaneous lesions,
pulmonary cvsts
and
spontaneous
pneumothorax

38. Syndrome Incidence Genes
Involved
Molecular
Pathway
affected
RenalType Others
characteristics
HPRC rare (Iess
than
1:1,500.00
MET C-MET Type 1 papillary
RCC
not specific
HLRCC Rare
(unknown)
FH Krebs cycle HLRC related
RCC
Multiples
cutaneous and
uterine
leyomiomas
SDH-RCC rare(unknow
n)
SDHB/SD
HC/
SDHD
Krebs cycle SDH related
RCC
Paraganglioma
s/
Pheocromocyt
oma GIST

39.  Hereditary kidney cancer accounts for 3 to 5%
of all kidney cancer
 Ten inherited cancer susceptibility syndromes
are associated with inherited risk of kidney
cancer and 12 genes have been identified

40. Genetics
• Autosomal Dominant
• Gene Locus on Chromosome 3p25
Incidence
• 1 in 35000 live births
Genetics
• Tumor Suppressor gene
• VHL gene product pVHL regulates function of HIF
• Reduced pVHL– no HIF degradation—increasedVEGF

42.  Sites involved
Organ Tumor Non-tumor lesions
Brain Hemangioblastoma
Eye Hemangioblastoma
Kidney CRCC Cyst
Adrenal Phaemochromocytoma
Pancreas NET Cyst
Inner Ear Endolymphatic Sac tumor
Epididymis PapillaryCystadenoma

43. Type 1 VHL loss or mutation that
affects the protein
folding
Haemangioblastoma
Renal Cell Carcinoma
Low risk of
phaeocromocytoma
Type 2A VHL missence mutation Haemangioblastoma
phaeocromocytoma
Low risk of Renal Cell
Carcinoma
Type 2B VHL missence mutation Haemangioblastoma
Renal Cell Carcinoma
Phaeocromocytoma
Type 2C VHL missence mutation Phaeocromocytoma only

44. Haemangioblastoma Clear Cell RCC Phaeochromocytoma
Papillary Cystadenoma

45. Diagnostic Criteria
Known Positive Family Hx – presence of
one:
Single retinal or cerebellar
hemangioblastoma
RCC
Pheochromocytoma
Negative Family Hx –
2 retinal or cerebellar
hemangioblastomas
Single hemangioblastoma and
additional characteristic lesion.
Screening and Follow-up
• Annual ophthalmologic evaluation and
visual field testing starting around age 2
• MRI of the brain and spine every 2 years
starting in early adolescence
• Annual abdominal US starting at age 5
• Abdominal CT or MRI starting at age 20
• Frequent blood pressure monitoring and
measurement of urinary catecholamine
levels or plasma metanephrine levels every
1–2 years starting at age 2
Treatment
• Hemangioblastomas
• Complete surgical resection
• Incomplete resection + external beam RT
•VEGF and PDGF pathway inhibitors (sunitinib and sorafinib)

46. Genetics :
• Autosomal dominant
• Gene : FLCN, Chromosome 17p, codes for protein “folliculin”
Clinical manifestations :
• Fibrofolliculomas (dysplastic hair follicules)
• Lung cysts
• Spontaneous pneumothorax
• Renal cancer
Incidence
• 1 of 200,000 people
• Hybrid oncocytic-
chromophobe type
• Chromophobe tumors
• Clear cell
• Oncocytomas
• Papillary renal cancers

47. Fibofolliculoma
Renal
Oncocytoma
Chromophobe
RCC

48. Major criteria
• At least five fibrofolliculomas, at least one
histologically confirmed, of adult onset or
• Pathogenic FLCN mutation
Minor criteria
• multiple lung cysts: bilateral basally located
lung cysts with no other apparent cause,
with or without spontaneous
pneumothorax
• renal cancer: early onset
Genetic Screening:
Germline FLCN testing is
recommended beginning
at age 21
Imaging Surveillance:
• Annual MRI or low dose
CT is recommended
beginning at age 20
• In patients without a
renal lesion MRI every 3
years is recommended

49. Hereditary Papillary
Renal Cancer
• Genetics
• Autosomal
Dominant
• Gene : MET
(activating mutation)
Chromosome 7q31.1
• Manifestations
• Papillary RCC type 1
Hereditary Leiomyoma
Renal Cell carcinoma
• Genetics
• Gene : FH,
chromosome 1q42
• Manifestations
• Papillary RCC type II
• Uterine Leiomyoma

50. Genetic Mechanism :
• SDH- kreb’s cycle enzyme
• Germline mutation in SDH B,C,D gene (SDHB has strongest association)
• SDHB gene locus- chromosome 1p36
• Succinate stabilises HIF
Incidence
• 0.1-2% of all renal cancers
Manifestation
• Paraganglioma
• Phaeochromocytoma
• Renal cell Carcinoma (Clear cell or chromophobe)

51.  BAP1 mutations and familial renal cancer
 Predispose to
▪ Familial clear cell renal cancer
▪ Uveal and cutaneous melanoma
▪ Mesothelioma
 Chromosome 3 translocations
 PTEN hamartoma tumor syndrome (Cowden
disease)

52.  Urothelial carcinoma :
 Associated with Lynch Syndrome
 Prostate Carcinoma :
 Polygenic Disorder
 BRCA1 and BRCA2 mutation :
▪ Increased risk of Prostate Cancer
▪ High grade and Advanced Stage

54. Syndrome Inheritance Gene Locus Gene Incidence Histology
FAP AD 5q21 APC 2-12% PTC_CMV
Cowden AD 10q23.3 PTEN,SDH,PIK3CA,
AKT1
35% PTC (follicular
variant), FTC,
Adenomatous
Nodule, C cell
hyperplasia
Carney AD 2p16,17q24 PPKAR1α 15% PTC,FTC,
adenomatous
nodule,Follicular
Adenoma
Wermer AR 8p11-p12 WRN 18% PTC,FTC,ATC
Mc-cune
Albright
20q13.2-13.3 GNAS PTC,FTC, Follicular
adenoma
DICER-1
syndrome
AD 14q32.13 DICER1 Rare Nodular Hyperplasia

55.  Lifetime risk for epithelial thyroid cancer is
approximately 10%
 Median age of onset was 37 years
 Youngest age at diagnosis was 7 years
 Thyroid lesions in CS
 Adenomatous Nodule
▪ Multiple, unencapsulated, homogenous, firm
 C cell hyperplasia
 Follicular Carcinoma
 PTC (Rare)

56. Adenomatous nodules in Cowden syndrome, routine stain.
(A) Solid adenomatous nodules surrounded by a thin rim of fibrous capsule, closely
dispersed in the thyroid gland.
(B) Each adenomatous nodule is composed of small follicles lacking abundant colloid
(C) Immunohistochemistry for PTEN shows loss of PTEN expression in an
adenomatous nodule in Cowden’s disease.

57.  160 fold increased risk of PTC
 Incidence : ~ 0.4% to 6.1% (Steinhagen E, et
al. 2012)
 Most thyroid cancer in individuals with FAP is
Cribriform-morular variant of PTC

58. Cribriform–morular variant of papillary thyroid carcinoma in familial adenomatous
polyposis, routine stain. (A, B)Typical cribriform arrangement composed of fused
follicles lined by tall cells and lumina lacking colloid. (C) Morular formation.

59.  Rare condition characterized
by
 Skin pigmentary abnormalities
 Myxomas
 Endocrine tumors or
overactivity
 Genetics
 Autosomal dominant
 Gene – PPKAR1A gene on
chromosome 17q

60.  Clinical Features/Major Diagnostic Criteria
 Spotty skin pigmentation
 Myxoma (cutaneous and mucosal)
 Cardiac myxoma
 Breast myxomatosis
 Primary pigmented nodular adrenocortical disease (PPNAD)
 Acromegaly as a result of growth hormone (GH)-producing
adenoma
 Large-cell calcifying Sertoli cell tumor (LCCSCT)
 Thyroid carcinoma or multiple, hypoechoic nodules on thyroid
ultrasound in a child younger than age 18 years
 Psammomatous melanotic schwannomas (PMS)
 Blue nevus, epithelioid blue nevus
 Breast ductal adenoma
 Osteochondromyxoma

61.  Cell cycle checkpoint kinase 2 (CHEK2)
 Tumor suppressor gene
 CHEK2 mutations associated with a
moderate increase in the risk for various
types of cancer
 Breast cancer - 2-4x increased risk
 Colorectal
 Prostate

62.  Siolek et al 2015 studied CHEK2 gene in
thyroid cancer patients
 468 cases and controls (Polish population)
 CHEK2 mutations seen in 15% of unselected
PTC patients and 6% of controls (p=0.006)
 7/11 women with breast and thyroid cancers
had CHEK2 mutations

63.  Tumor susceptibility
syndrome
 Confers increased risk for-
 Pleuropulmonary blastoma
(PPB)
 Ovarian sex cord-stromal
tumors (such as Sertoli- Leydig
cell tumor or juvenile granulosa
cell tumor)
 Cystic nephroma
 Thyroid gland neoplasia
 Rhabdomyosarcoma
 Pituitary blastoma
 Wilm’sTumor

64.  Increased risk of developing thyroid cysts
and/or multinodular goiter (MNG) in families
with a germline DICER1 mutation
 Risk of developing syndrome-associated
thyroid cancer (papillary or follicular)

65.  Birt-Hogg-Dube syndrome – cutaneous
manifestations, pulmonary cysts/history of
pneumothorax, and various types of renal
tumors
 Hyperparathyroidism-jaw tumor syndrome
(HPT-JT)
 Hereditary
Paraganglioma/Pheochromocytoma (SDHB
and SDHD)
 Multiple Endocrine NeoplasiaType 1

67. MEN 1 MEN 2
•Parathyroid hyperplasia or adenoma
•Islet cell hyperplasia, adenoma, or
carcinoma
•Pituitary hyperplasia or adenoma
•Other less common manifestations:
foregut carcinoid, pheochromocytoma,
subcutaneous or visceral lipomas
MEN2A
• MTC
•Pheochromocytoma
•Parathyroid adenoma
•MEN2A with cutaneous lichen amyloidosis
• MEN2A with Hirschsprung disease
MEN2B
• MTC
• Pheochromocytoma
• Mucosal and gastrointestinal neuromas
• Marfanoid features

68. Chr. 10q11.2

70. Medullary thyroid carcinoma in multiple endocrine neoplasia syndrome, routine stain. (A) Medullary thyroid
carcinoma featuring lobular and solid architectures with stromal calcitonin amyloid deposits.Tumour cells are
variable in size and shape, with slightly granular cytoplasm and punctate coarse chromatin. (B) Medullary thyroid
microcarcinoma in a young patient subjected to prophylactic thyroidectomy.

73. Syndrome Chromosome/Gene CNS tumors
Ataxia telangiectasia (AR) 11q22/ATM Meningioma, glioblastoma,
pilocytic astrocytoma,
medulloblastoma
Cowden (AR) 10q23/PTEN Dysplastic cerebellar
gangliocytoma, glial tumors
FAP (AD) 5q21/APC Medulloblastoma, astrocytoma,
ependymoma
Hereditary non– polyposis-
related colorectal cancer
(AD)
3/MLH1
7/PMS2
2/MSH2
2/MSH6
Glioblastoma, other glial tumors
Gorlin (AD) 9q/PTCH
10q24/SUFU
Desmoplastic medulloblastoma,
meningioma, oligodendroglioma,
craniopharyngioma

74. Syndrome Chromosome/Gene CNS tumors
Multiple endocrine
neoplasia 1 (AD)
11q13/MEN1 Parathyroid adenoma, pancreatic
and duodenal neuroendocrine
tumors
Neurofibromatosis type 1 17q11/NF1 Optic/chiasmatic gliomas,
plexiform neurofibromas, pilocytic
astrocytoma, glioblastoma
Neurofibromatosis type 2 22q12/NF2 Vestibular schwannoma,
meningioma, ependymoma
Tuberous sclerosis
complex
9q34/TSC1
16q13/TSC2
Subependymal giant cell
astrocytoma
von Hippel–Lindau 3p25/VHL Hemangioblastoma.
endolymphatic sac tumor

75. Genetics
• Autosomal dominant
• Gene locus on Chromosomes 9q31 and 16q13
• 70% cases sporadic
• Wide variety of germline mutations
MOLECULAR
• TSC1 -> Hamartin
• TSC2 ->Tubulin
• Tumor suppressor genes
• Heterodimerize to inhibit mTOR pathway (mammalian target of rapamyacin)
• Cell proliferation and growth through mRNA translation and ribosome synthesis
INCIDENCE1
• in 6,000 to 10,000 live births
Manifestations
Giant Cell Astrocytoma
Ependymoma
Bilateral Renal Angiomyolipomas
Renal Cell Carcinoma (Childhood)
Cardiac Rhabdomyoma
Other CNS Abnormalities:Tubers,
Psychomotor delay, Seizures

76. Definite diagnosis: 2 major or 1 major and 2 minor criteria
Probable diagnosis: 1 major and 1 minor criteria
Possible diagnosis: 1 major or 2 minor criteria
Major Criteria:
• Skin manifestation (facial angiofibroma, ungual fibroma, > hypomelanotic macules, shagreen
patch)
• Brain and eye lesions (cortical tuber, subependymal nodules, subependymal giant cell
astrocytoma, multiple retinal nodular hamartomas)
• Tumors in other organs (cardiac, rhabdomyoma, lymphangioleiomyomatosis, renal
angiomyolipoma)
Minor Criteria:
• Pits in dental enamel
• Rectal polyps
• Bone cysts
• Cerebral white matter migration abnormalities
• Gingival fibromas
• Nonrenal hamartomas
• Retinal achromic patches
• Confetti skin lesions
• Multiple renal cysts
Screening and Follow-up :
• Funduscopic examination
• Renal US or CT
• Brain MR imaging
• Echocardiography/Electrocardiography
Treatment
• SEGA
• Surgical resection
• Rapamycin can cause regression and
prevention of epilepsy
Angiofibroma Angiomyolipoma SEGA

77. GENETICS
• Autosomal dominant
• Gene locus on Chromosome 17q11.2
• Penetrance = 100%
• ~50% new mutations
MOLECULAR
• NF gene -> Neurofibromin
• Negative regulator of RAS oncogene
• Tumor suppressor gene
• Inactivation causes cell growth and tumor
development
• Regulates neuroglial progenitor function
INCIDENCE
• 1 in 2,500 to 3,000 live births
Manifestations
OpticGlioma (Nerve and
Chiasmatic)
Neurofibrosarcoma
GBM
PilocyticAstrocytoma
Plexiform Neurofibroma
Pheochromocytoma
Embryonal RMS
Leukemia (chronic
myelogenous)
MPNST
Neuroblastoma
GIST
 Diagnostic Criteria
 Requires the presence of at least 2 of the following criteria
 > 6 Café-au- lait macules (>5 mm in children and >15 mm
in adults)
 > 2 Cutaneous or subcutaneous neurofibromas or one
plexiform neurofibroma
 Axillary or inguinal freckling
 Optic pathway glioma
 > 2 Lisch nodules (small elevated hamartomas of the iris)
 > 1 Distinctive osseous lesion (sphenoid wing dysplasia or
thinning of long bone cortex)
 First-degree relative with NF1
Screening and Follow-up
• Yearly physical exam
• Yearly ophthalmologic exam in early childhood ( up to age 5)
• Regular developmental assessment
• Routine blood pressure monitoring
• Appropriate monitoring by a specialist according to CNS, skeletal, or
cardiovascular abnormalities
Treatment
Optic glioma
• Surgery
• RT (after age 5)
• Chemotherapy (carboplatin + vincristine)
Plexiform Neurofibromas
• Tipifarnib (RAS inhibitor)

78. GENETICS
• Autosomal dominant
• Gene locus on Chromosome 22q11
• 100% penetrance
MOLECULAR
• Gene -> Merlin
• Cytoskeleton organizing protein
• Tumor suppressor protein
• Involved in cell proliferation via the PAK/Rac signaling system
• Cell membrane stability, motility, and intracellular adhesion
INCIDENCE
• 1 in 25,000 to 40,000 live births
Manifestations
• Vestibular Schwannoma (Bilateral)
• Meningioma
• Ependymoma
• Pilocytic Astrocytoma
Diagnostic Criteria
 Definite diagnosis if either condition is fulfilled
 Bilateral vestibular schwannomas
 1st-degree relative with NF2 and either
▪ Unilateral vestibular schwannoma <30 years
▪ Any 2 of the following: meningioma, schwannoma, glioma,
posterior subcapsular lens opacity or cerebral calcifications
 Probable diagnosis if either condition is fulfilled
 1) Unilateral vestibular schwannoma at <30 years and at
least one of the following: meningioma, schwannoma,
glioma, posterior subcapsular lens opacity
 2) Multiple meningiomas and either of the following:
schwannoma, glioma, posterior subcapsular lens
opacity
Screening and Follow-up
• Annual MRI starting at age 10 to at least age 40
• Frequent hearing and vision evaluation
Treatment
Vestibular schwannoma
• Surgical resection (translabyrinthine or suboccipital
retrosigmoid)
• Radiation therapy
• Stereotactic radiosurgery vs.External beam

79. GENETICS
• Germline mutation in SMARCB1 (aka INI-I)
• Seen in 40-50% of familial cases
• Tumor suppressor gene
MOLECULAR DIAGNOSIS
• SMARCB1-associated schwannomatosis
• Two or more pathologically proved schwannomas or meningiomasAND
genetic studies of at least two tumors with loss of heterozygosity (LOH)
for chromosome 22 and two different NF2 mutations; if there is a
common SMARCB1 mutation
• Pathologically proved schwannoma or meningiomaAND germline
SMARCB1 pathogenic mutation
• Diagnostic Criteria
Two or more non-intradermal schwannomas, one with pathological
confirmation, including no bilateral vestibular schwannoma by MRI
• One pathologically confirmed schwannoma or intracranial meningioma
AND affected first-degree relative
• Exclusion criteria:
•Germline pathogenic NF2 mutation
•Fulfill diagnostic criteria for NF2
•First-degree relative with NF2
•Schwannomas in previous field of radiation therapy only

80. Turcot Syndrome
• GENETICS
• Autosomal dominant
• Gene locus on Chromosome 5
• MOLECULAR
• PMS2 -> Postmeiotic segragation
increased
• MLH1 -> MutL homolog 1
• MSH2 -> MutS homolog 2
• DNA mismatch repair (MMR) genes
• Disruption of the WNT signalling pathway
• Manifestations
• Medulloblastoma
• Glioblastoma Multiforme
• Anaplastic Astrocytoma
• Ependymoma
• Colon Cancer/Multiple Colonic Polyps
Gorlin Syndrome
• GENETICS
• Autosomal dominant
• Gene locus on Chromosome 9q
• MOLECULAR
• PTCH -> Drosophila Melanogaster Patched
GeneEncodes a transmembrane receptor
for secreted ligand sonic hedgehog
(SHH)Essential for cerebellar development
• Manifestations
• Desmoplastic Medulloblastoma
• Multiple Basal Cell Carcinomas

81. GENETICS
• Autosomal recessive
• Gene locus on Chromosome 11q22-23
MOLECULAR
• ATM –
• Ataxia telangiectasia mutated
• Protein kinase
• DNA damage response and associated cell-cycle checkpoint regulation
INCIDENCE
• 1 in 40,000 to 100,000 live births
Manifestations
PilocyticAstrocytoma
Medulloblastoma
Glioblastoma Multiforme
Lymphoma/Leukemia
Lung Cancer
Breast Cancer
Ovarian Cancer
Stomach Cancer
Other CNS
Abnormalities:Vascular
telangiectasiasCerebellar
atrophy
Diagnostic Criteria
Progressive cerebellar dysfunction
between ages one and four years.
Presenting as:
Gait and truncal ataxia
Head tilting
Slurred speech
Oculomotor apraxia and uneven
(interrupted or “bumpy”)
tracking across a visual field

82. Genetics
• Germline mutation in SMARCB1 in
chromosome 22q11.23 (RTPS 1)
• Mutation of in SMARCA4 in chromosome
19p13.2
Sites of involvement
• CNS
• AT/RT
• Medulloblastoma, Choroid Plexus Ca,
Supratentorial PNET
• Extraneural
• Bilateral malignant rhabdoid tumors of
Kidney

83. Syndrome Mode of
Inheritance
Genes Component
Malignancies
Wiskott-Aldrich
syndrome
X-linked recessive WAS NHL
Severe combined
immune deficiency
X-linked recessive,
recessive
IL2RG,ADA, JAK3,
RAG1, RAG2, IL7R,
PTPRC, DCLRE1C
B-cell lymphoma
X-linked
lymphoproliferativ
e syndrome
X-linked recessive SH2D1A Lymphoma

84. Lynch Syndrome and
Colorectal Cancer
1

85. Lynch Syndrome (LS)
• Familial Predisposition to Colorectal and other cancers
• Autosomal Dominant
• Henry Lynch, MD 1966
• Hereditary Nonpolyposis Colorectal Cancer (HNPCC)
2

86. Colorectal Cancer in LS
• Cancers more frequently
• Cancers at younger age (40’s)
• Right sided cancers
• Adenoma to carcinoma sequence more rapid
• Synchronous and Metachronous Cancers
• Lifetime Risk 10-74% (vs. 5.5% without)
• Better Prognosis
3

87. Genetics of CRC
Sporadic
(65%–85%)
Familial
(10%–30%)
Lynch syndrome
(3%)
Familial adenomatous
polyposis (FAP) (1%)
Rare CRC
syndromes
(<0.1%)
MYH associated
polyposis (MAP)
(1%)

88. Other LS Cancers
Cancer Incidence (%) Incidence LS (%)
Endometrium 2.7 14-71
Stomach <1 0.2-13
Ovary 1.6 4-20
Hepatobiliary Tract <1 0.02-4
Urinary Tract <1 0.2-25
Small Bowel <1 0.4-12
Brain/CNS <1 1-4
Sebaceous Neoplasm <1 1-9
Pancreas 1.5 0.4-4
Prostate 16.2 9-30
Breast 12.4 5-18

89. A Classic HNPCC/Lynch Family
CRC
dx 50s
CRC
dx 45
CRC
dx 61
CRC
dx 75
Ovarian
Ca, dx 64
CRC
dx 48
CRC
dx 52
Endometrial
Ca, dx 59
CRC
dx 42
45

90. Clinical Diagnosis of LS
Amsterdam I Criteria (1991)
1. Three or more relatives with histologically verified colorectal cancer,
1 of which is a first-degree relative of the other two. Familial
adenomatous polyposis should be excluded.
2. Two or more generations with colorectal cancer.
3. One or more colorectal cancer cases diagnosed before the age of 50
years.

91. Clinical Diagnosis of LS
Amsterdam II Criteria (1999)
1. Three or more relatives with histologically verified HNPCC-
associated cancer (colorectal cancer, cancer of the endometrium, small
bowel, ureter, or renal pelvis), 1 of which is a first-degree relative of
the other 2. Familial adenomatous polyposis should be excluded.
2. Cancer involving at least 2 generations.
3. One or more cancer cases diagnosed before the age of 50 years.

92. Clinical Diagnosis of LS
Revised Bathesda Guidelines (2004)
1. CRC diagnosed at younger than 50 years.
2. Presence of synchronous or metachronous CRC or other LS-associated
tumors.*
3. CRC with MSI-high pathologic-associated features (Crohn-like lymphocytic
reaction, mucinous/signet cell differentiation, or medullary growth pattern)
diagnosed in an individual younger than 60 years old.
4. Patient with CRC and CRC or LS-associated tumor* diagnosed in at least 1
first-degree relative younger than 50 years old.
5. Patient with CRC and CRC or LS-associated tumor* at any age in 2 first-
degree or second-degree relatives.
* LS-associated tumors include tumor of the colorectum, endometrium,
stomach, ovary, pancreas, ureter, renal pelvis, biliary tract, brain, small bowel,
sebaceous glands, and kerotoacanthomas.

93. LS Genetic Alterations
• Microsatellite Instability (MSI)
• MSI - High
• MSI - Low
• MS - Stable
• MSI – High Better Prognosis
• Most MSI Colorectal Cancers are not LS (12% of sporadic CRC)
10

94. Microsatellite Instability
-CG-
-CGCGCGCG
-CG-
-CGCGCGCG
-CG-
-CGCGCGCG
-CG
-CGCGCGCG-
-CG-
-CGCGCGCGCG-
-CG-
-CGCGCG-
-CG-
-CGCG-
-CG-
-CGCG-
-CGCGCG-
-CGCGCGCGCG-
Normal Cells
Tumor Cells
Microsatellite Instability
Normal Microsatellites

95. Mismatch Repair (MMR) Genes and Proteins
• Proofread Replicated DNA
• Problem will be most obvious in repetitive sequences
• Defect in both copies leads to cancer
• If already carries one defect, at high risk to develop a second defect –
Lynch Syndrome
• LS is Autosomal Dominant

96. Carrier Parent
Non-carrier Parent
Autosomal Dominant Inheritance
Aa aa
Aa Aa aa aa
Carrier Carrier Non-carrier Non-carrier
1/2 1/2

97. Mismatch Repair (MMR) Genes
• MLH1
• MSH2
• MSH6
• PMS2
• EPCAM (Promotor for MSH2)
14

98. MLH1
MSH2
MSH6
PMS2

99. Universal Tumor Testing for LS
• MSI Testing
• Inexpensive
• Prognostic and Treatment Information
• MMR Protein Testing
• Inexpensive
• Directs which gene to look at
• Confirm Positive Results with Gene Analysis
16

100. Followup
• Genetic Counseling
• Gene Testing Appropriate Family Members
• Familial Colorectal Cancer Type X (FCRCTX)
17

101. Treatment of Colon Cancer in LS Patients
• Partial Colectomy
• Risk of Metachronous Cancer 16-19% at 10 years
• Total or Subtotal Colectomy with Ileorectal/Ileosigmoid Anastomosis
• Risk of Metachronous Cancer 0-3.4% at 10 years
• Diarrhea
• Need to consider age and sphincter function
18

102. Treatment of Rectal Cancer in LS Patients
• Resection of Rectum with Anastomosis
• Risk of Metachronous Cancer 69% at 30 years with colonoscopy every 1.6
years
• Total Proctocolectomy with Ileal Pouch-Anal Anastomosis (IPAA)
• Standard of Care for cancer with UC or FAP
• LS patients older
• Total Proctocolectomy with End Ileostomy
19

103. CRC Screening in LS Patients
• Colonoscopy every 1-3 years leads to fewer CRC and at a later age
than unscreened
• Colonoscopy every 1-3 years leads to similar CRC mortality compared
to those without LS, although more CRC diagnosed
• More frequent colonoscopy (≤ 2 years) better
20

104. CRC Screening in LS Patients
Guideline: Screening for CRC by colonoscopy is recommended in
persons at risk (first-degree relatives of those affected) or affected with
LS every 1 to 2 years, beginning between ages 20−25 years or 2−5
years before the youngest age of diagnosis of CRC in the family if
diagnosed before age 25 years.
May need to adjust based on exact family history and which gene is
mutated.
21

105. Endometrial Cancer in LS
• Second most common cancer
• 75% Stage I and 88% 5 year survival
• Hard to prove screening helps
• Annual Pelvic Exam and Endometrial Sampling Offered Starting at
Age 30-35
22

106. Ovarian Cancer in LS
• No data as to screening
• Transvaginal Ultrasound and CA-125 Screening does not seem to help
with BRCA1 and BRCA2 patients
• Annual Transvaginal Ultrasound Offered Starting at Age 30-35
23

107. Prophylactic Hysterectomy and
Oophorectomy in LS
• Retrospective analysis of 315 women with MMR mutations
• 33% Uterine cancer without surgery
• No uterine cancer with surgery
• 5.5% Ovarian cancer without surgery
• No ovarian cancer with surgery
• Guideline: Hysterectomy and Oophorectomy after childbearing or at
age 40
24

108. Gastric Cancer in LS
• Lifetime Risk 0.2-13%
• EGD every 2-3 years beginning age 30-35
• Treat H.pylori if found
• Modify based on family history and gene mutation
25

109. Urinary Cancers in LS
• Not much data screening (urinalysis, urine cytology) helps
• Inexpensive
• Noninvasive
• Easy
• Consider annually starting age 30-35
26

110. Other Cancers in LS
• No screening or no increased screening beyond that for usual
population
• Pancreatic
• Small Intestine
• Prostate
• Breast
• Either no clear increased risk or no good screening test
27

111. Questions?
28