Cancer is caused by uncontrolled cell growth and spread. Cancer cells form tumors and spread through the body. There are many types of cancer that can affect different parts of the body. Cancer development is influenced by both external factors like lifestyle and environment as well as internal genetic factors. Cancer progression occurs through multiple genetic mutations over time that allow cancer cells to evade control mechanisms and continue growing and spreading.

1. What is cancer?
• Cancer cells are cells that divide relentlessly, forming
solid tumours or flooding the blood with abnormal
cells. Cell division is a normal process used by the
body for growth and repair. A parent cell divides to
form two daughter cells, and these daughter cells are
used to build new tissue, or to replace cells that have
died as a result of ageing or damage. Healthy cells
stop dividing when there is no longer a need for more
daughter cells, but cancer cells continue to produce
copies. They are also able to spread from one part of
the body to another in a process known
as metastasis.

2. Cancer information
• One in three people in the Western world develop cancer
and one in five die of the disease
• There are approximately 200 types of cancer, each with
different causes, symptoms and treatments
• In 2007, 297,991 people were newly diagnosed with
cancer in the UK
• An individual's risk of developing cancer depends on
many factors, including age, lifestyle and genetic make-up

3. Classification
• Carcinoma
• the majority of cancer cells are epithelial in origin,
beginning in the membranous tissues that line the
surfaces of the body.
• Leukaemia
• originate in the tissues responsible for producing
new blood cells, most commonly in the bone marrow.
• Lymphoma and myeloma
• derived from cells of the immune system.

4. • Sarcoma
• originating in connective tissue, including fat, muscle
and bone.
• Central nervous system
• derived from cells of the brain and spinal cord.
• Mesothelioma
• originating in the mesothelium; the lining of body
cavities.

5. Carcinoma
Leukaemia
Lymphoma

6. Myeloma Sarcoma
Mesothelioma

7. Histology
• Cancer cells have distinguishing histological features
visible under the microscope. The nucleus is often
large and irregular, and the cytoplasm may also
display abnormalities.

8. Tumour suppressor gene
TS
Cancer
These genes normally function to PREVENT
cell growth/division

9. Oncogene
Cancer
Ras
Genes which normally function to PROMOTE cell
growth/division in a controlled manner

10. Causes
Life cycle of a cancer cell

11. • Cancer cells are created when the genes
responsible for regulating cell division are
damaged. Carcinogenesis is caused by
mutation and epimutation of the genetic
material of normal cells, which upsets the
normal balance between proliferation and cell
death. This results in uncontrolled cell division
and the evolution of those cells by natural
selection in the body.

12. Pathology
• Immune system cells, such as White Blood
cells are thought to use a dual receptor system
when they determine whether or not to kill
sick, or damaged human cells. If a cell is under
stress, turning into tumors, or infected,
molecules including MIC-A and MIC-B are
produced to put on the surface of the
cell.[8] These work to help the white blood
cells to detect and kill cancer cells.[9]

13. Discovery
• Cancer is an ancient disease with descriptions
dating back to ancient Egypt. In 2016, a 1.7
million year old osteosarcoma was reported,
representing the oldest documented
malignant hominin cancer

14. Telomerase
• Cancer cells have unique features that make
them "immortal" according to some
researchers. The enzyme telomerase is used
to extend the cancer cell's life span. While the
telomeres of most cells shorten after each
division eventually causing the cell to die,
telomerase extends the cell's telomeres. This
is a major reason that cancer cells can
accumulate over time creating tumors.

15. Cancer stem cells and drug resistance
A diagram illustrating the distinction between cancer stem cell targeted
and conventional cancer therapies

16. • Scientists have discovered a molecule on the surface of
tumors that appears to promote drug resistance—by
converting the tumor cells back into a stem cell-like
state. When the tumor cells began to exhibit drug
resistance, the cells were simultaneously transforming
into a stem cell-like state, which made them impervious
to the drugs. It appeared that the treatment itself was
driving this transformation by activating a specific
molecular pathway. Luckily, several existing drugs, such
as Bortezomib for example, can attack this pathway and
reverse the cellular transformation, thus‘re-sensitizing’
the tumor to treatment.

17. Cancer progression
Benign Tumour
In situ cancer
Invasive cancer
Metastatic
cancer
Mutations in multiple cancer genes are required for the
development and progression of a single cancer

18. www.flickr.com: lastexit
External causes of cancer:
ultraviolet radiation

19. External causes of cancer:
tobacco smoke

20. Lifestyle factor: diet

21. Biological factor: virus
• HPV is a cause of
cervical cancer
• Proteins from the virus
activate and deactivate
cancer genes
• The role of HPV in
cervical cancer has led
to the development of
vaccines HPV in cervical epithelium
Credit: MRC NIMR, Wellcome Images

22. Activity
• The KRAS gene codes for a signalling molecule
• Mutations in KRAS are present in many cancers,
including pancreatic cancer
• You have to look for the mutations by comparing
healthy DNA sequence with tumour DNA sequence
• Not all of you will find a mutation

23. What’s the impact?
• KRAS helps to transmit external growth signals to the cell nucleus,
driving normal cell growth. It is:
– Activated when it binds GTP
–
Inactivated or “switched off” when GTP is hydrolysed to GDP

24. • Cancer Research UK
http://info.cancerresearchuk.org/cancerstats/incidence/?a=5441