Normal Vs. Cancer cell differentiation

1. Oncology
normal cell
and
cancer cell
-Ms. Pooja Murkar

2. CANCER
 An uncontrolled division of abnormal cells
in a partof the body is calledcancer.
 When good cells gobed.
 Loss of Cell-cycle Control.
 Before a cell divides, the DNA is checked to
make sure it has replicated correctly. (If
DNA does not copy itself correctly, a gene
mutationoccurs.

3. Normal Cell VS Cancer Cell

4. Normal Cell VS Cancer Cell

5. Normal Cell VS Cancer Cell

6. Normal Cell VS Cancer Cell

7. Normal Cell VS Cancer Cell

8. Normal Cell VS Cancer Cell

9. Normal Cell VS Cancer Cell
 Cells in culture and in vivoexhibit
contact-inhibition
 Cancer cells lack contactinhibition
feedback mechanisms. Clumps or
foci develop.

11. DNA
DNA
DNA
DNA
DNA
DNA
DNA
DNA
DNA
G1
Cell growth
S
DNA replication
G2
Cell growth
preparation for
division
Mitotic Phase (M)
Interphase
Interphase
Interphase

12. The Characteristics of Cancer
• As genes switch on and off, they determine
when and how fast the cell will grow and
divide, when it will stop dividing, and even
when it will die
• Cancer can result when controls over cell
division are lost

13. Cancer Cells Are Abnormal in Their
Growth and Appearance

14. (1) Malignant Tumor
 Invadeorspread tootherpartsof the body.
 High rate of division.
 Spread by forming Metastasis.
 Cells travel throughcirculation.
 Very difficult totreat.

15. Cancer Metastasis
 Metastasis is the spread of cancer toother location in
the body.
 The new tumorsarecalled metastatic tumors, while
theoriginal site is called primary tumor.
 Basal lamina of epithelium normally providesbarrier.
 Malignant tumorcells break, free of attachments to
adjoining cells.
 Attach to basal lamina.
 Secreteenzymes thatdigestextracellularproteins.
 Migrate into circulatorysystem.

17. (2) Benign Tumor
 Do notspread tootherpartof the body.
 Generally localized and of smallsize
 Slow rate of division.
 Cells thatclosely resemble, and may function, like
normal cells.
 Do not break outof originating organ.
 Easily to removed bysurgery.

18. Tumor is of twotypes:-
Malignant tumor (cancerous)
Benign tumor (non-cancerous)

19. Main Features of Benign and
Malignant Tumors

20. Classification of Cancer
 Cancers areclassified by the typeof cell.
(1) Carcinoma
(2) Sarcoma
(3) Lymphoma and Leukemia
(4) Germ Cell Tumor
(5) Blastoma

21. A Cancer Cell’s Structure Is Abnormal
• Cancer is a result of a series of mutations in
the cell’s genes
– Larger cell nucleus and less cytoplasm
– Loss of structural specialization
– Cytoskeleton shrinks
– Plasma membrane proteins could be lost or
altered
– New plasma membrane proteins may appear
– Changes passed on to cell’s descendants

23. Carcinogenesis

24. Carcinogenesis Occurs in Predictable Steps

25. Classification (Cont…)
 (1) Carcinoma:
Cancers derived from epithelialcells.
 (2) Sarcoma:
Cancers arising from connective tissue (i.e.bone,
cartilage, blood etc).
 (3) Lymphoma and Leukemia:
These twoclasses of cancerarise from hematopoietic
(blood forming) cells.

26. Classification (Cont…)
 (4) Germ Cell Tumor:
Cancers derived from pluripotent cells, most often
presenting in the testicles and ovary (seminomaand
dysgerminoma respectively).
 (5) Blastoma:
Cancers derived from immature “precursor” cellsor
embryonic tissue.

27. Properties of Cancer Cells
 Cancercells show uncontrolled mitoticdivisionscausing unorganised
growth.
 Due touncontrolled growthand divisionof cells, a tumor(alsocalled
Neoplasm is generallyformed).
 Theyare far less adhesive than the normal cells.
 Theyexhibita numberof alterationson cell surface, in thecytoplasm
and in theirgenes.
 They do not undergodifferentiation.
 They lose theability tocommunicatewith othercells through chemical
signals.
 Theyalso lose sensitivitytoanti-growthsignals from surrounding cells.
 They lose theadhesion molecules that keep them bonded to
neighboring cells.
 Cancerarises froma loss of normal growthcontrol.

28. Cont….
 Cancer is agenetic disease:
–Inherited cancer
–Sporadiccancer
 Cancertypically involvesachange in geneexpression/function:
–Qualitativechange
–Quantitativechange
 lack of contactinhibition
 Loss of limitationson the numberof cell divisions
 Abilitytogrow in culture (medium) – normal cells do notgrowwell in
culture.
 In laboratorycultures, normal cells divideonlywhen attached toa
surface.
 Angiogenesis – secretesubstances thatcause blood vessels togrow
towards tumor.

29. Causes of Cancer
 The great majorityof cancers 90-95% cases, aredue to
environmental factors.
 The remaining 5-10% are dueto inherited genetics.

30. (1) Environmental Factors
 Environmental factors include;
(1) Tobacco(25-30%)
(2) Diet and obesity(30-35%)
(3) Infections (15-20%)
(4) Radiation (both ionizing & non-ionizing,
upto 10%)
(5) Stressand
(6) Environmental pollutants

31. (2) Inherited Genetics
 Cancer is fundamentallya diseaseof tissuegrowth
regulation failure.
 In order fora normal cell to transform intoa cancer
cell, the genes that regulate cell growth and
differentiation must bealtered.
 The affected genes aredivided into two broad
categories;
(i) Oncogenes
(ii) Tumor SuppressorGenes

32. (Cont…)
 (i) Oncogenes:
Oncogenesaregenes that promotecell growthand
reproduction.
 (ii) Tumor SuppressorGenes:
Tumorsuppressorgenes aregenes that inhibitcell
division and survivals.

35. Colon cancer results from genetic
alterations in multiple genes
Inherited mutations in the APC gene dramatically
increase risk of colon cancer

36. Cancer Usually Involves Several Genes
• Proto-oncogenes
– In normal cells
• Code for proteins involved in the stimulus of cell
division
– If altered, may form oncogenes
• Alone, do not cause malignant cancer
• Require other mutations, including one in a tumor
suppressor gene

37. • Tumor suppressor genes
– Stop cell growth and division; prevent cancer
formation
– May prevent expression of oncogenes
Cancer Usually Involves Several Genes

38. Types of cancer genes
Types of
proteins
Mutated
function
Normal
function
Type of
gene
Enzymes for
mismatch or
excision repair
Fail to repair
DNA mutations
Repair DNA
mutations
DNA repair
gene
mutation
Checkpoint
molecules
Fails to suppress
division
Suppresses cell
division
Tumor
suppressor
gene
Growth factors
Promotes
division -
abnormal time
or cell type
Promotes
division
Oncogene

39. Other Factors Also May Lead to Cancer
• Chemical carcinogens
– Carcinogens: cancer-causing substances that can lead
to a mutation in DNA
• Asbestos, vinyl chloride, and benzene
• Hydrocarbons in cigarette smoke
• Aflatoxin: fungal product
• Radiation
– UV from the sun and tanning lamps
– X-rays: medical and dental
– Radon, cosmic rays, and gamma radiation

40. Cruciferous vegetables can lower cancer risk

41. Other Factors Also May Lead to Cancer
• Breakdowns in immunity
– Healthy immune system can target and destroy
cancer cells
– When cancer cells have altered proteins at its
surface, cells are not destroyed
– Risk of cancer increases:
• With age
• When an immune system has been suppressed for a
long time
– HIV infection
– Immunosuppressant drugs
– Anxiety and depression

42. Focus on Environment: Cancer Risk
from Environmental Chemicals
• Exposure to pesticides
– Agricultural chemicals in food and airborne
chemicals due to spraying programs
– Reduce exposure; how?
• Industrial chemicals
• Ames test
– Assess chemical’s ability to cause mutations

43. Some Industrial Chemicals Linked to
Cancer

44. Cancer Screening and Diagnosis

45. Blood Tests Can Detect Chemical
Indications of Cancer
• Tumor markers
– Produced by particular types of cancer cells
– Produced by certain cells in response to cancer
– Detected by blood tests
• HCG
• PSA: prostate-specific antigen

46. Medical Imaging Can Reveal the Site
and Size of Tumors
• Medical imaging
– MRI (magnetic resonance imaging): reveals
tumors obscured by bone
– X-rays
– Ultrasound
– CT (computerized tomography)

47. Medical Imaging Can Reveal the Site
and Size of Tumors
• Radioactive tracers
– Tracked using a PET scanner
• Diagnosis of thyroid cancer using radioactive iodine
• Radioactively labeled monoclonal antibodies
– Useful in the location and size of certain tumors in
the colon, brain, and bone
• DNA probe: locates mutated genes, e.g., p53

48. Radioactive Tracers Also Can Reveal Cancer
Tumors

49. Biopsy Is the Only Sure Way to
Diagnose Cancer
• Biopsy
– Removal and microscopic examination of tissue
• Seven common cancer signs: CAUTION

50. Light Microscope Image Shows
Cancerous Cells in Breast Tissue

51. Cancer Treatment and Prevention
• When a person is diagnosed with cancer, a
variety of weapons are available to combat it
 Chemotherapy drugs
 Radiation therapy
 Surgery

52. Chemotherapy and Radiation Kill
Cancer Cells
• Chemotherapy
– Drugs used to kill cancer cells; disrupt some aspect
of cell division
– Toxic to healthy cells; hair, bone marrow,
lymphocytes, and epithelial cells of intestinal lining
– Side effects include hair loss, nausea, vomiting, and
reduced immune responses
– Genetic approach to chemo in the future

53. Chemotherapy and Radiation Kill
Cancer Cells
• Radiation therapy
– Used when cancer is small or has not
spread
– Radioisotopes used, e.g., Ra-226 and
Co-60
• More precise treatments
– Monoclonal antibody treatment
– Interferon treatment; limited at
present

54. Cancer Causes and Contributing Factors

56. Apoptosis (Programmed Cell Death)
 Apoptosis is a tightly regulated form of cell death, also
called the programmed cell death. Morphologically, it is
characterized by chromatin condensation and cell
shrinkage in theearly stage. Then the nucleus and
cytoplasm fragment, forming membrane-bound apoptotic
bodies which can be engulfed byphagocytes.
 Initiated by signal transductionprocess.
 Does not causeinflammation.
 Ends with fragmentation of cell into smallerbodies.

57. Necrosis (Lethal Injury)
 In contrast, cells undergo another form of cell death,
necrosis, swell and rupture. The released intracellular
contents can damagesurrounding cells and often cause
inflammation.
 Un-programmed cell death and living tissues. (oppositeto
apoptosis).
 Initiated by direct cell damage mostlyphysically.
 Cause inflammation.
 Ends with total cell lysis.