Cell cycle disregulation is a hallmark of cancerous tumor cells. Cancer occurs due to failures in the regulation of the cell cycle, which normally controls cell division. There are three main checkpoints (G1, G2, M) that monitor DNA for damage and stop the cell cycle if needed. Mutation of key tumor suppressor genes like RB1, TP53, and CDKs that control progression through these checkpoints can cause unchecked cell growth and tumor formation. Carcinogens like tobacco, alcohol, and ultraviolet light can damage DNA and cause mutations that lead to cancer by disrupting the cell cycle. Preventing exposure to carcinogens and maintaining a healthy lifestyle can reduce cancer risks by 30-40%.

2. Presented by ;Qasim Ali
Presented to ; Dr.Sir
Kaleem
Subject; Cell & Molecular
Biology
Date of presentation
11/1/2017
Topic ;Cell cycle disregulation in
Cancer
Department of Zoology, KUST

3. Cell Cycle Disregulation in Cancer
• Definition;
Cell cycle disregulation is a hallmark of
tumour cell. The ability of normal cell to
undergo cell-cycle arrest after damage to DNA
is crucial for the maintenance of genomic
integrity. The biochemical pathways that stop
the cell cycle in response to cellular stressors
are called checkpoints.

4. Any cell have 3 choice of behaviour
• To complete another round of division,
• Can out of cell cycle to become a non-dividing
cell,
• Or it can die,

5. Check points
• A check point is the cell cycle is a critical control
point where stop and go signal regulate the
cycle.
• Cyclins are protein molecules that bind to
enzymes called CDKs.
• Cyclins = that regulate cell cycle.
• 3 major check points are G1, G2 and M.

6. Continuous

7. Cancer
• Cancer is uncontrolled growth and division of
cell – due to failure in the regulation of the cell
cycle.
• Tumour formed-masses of cell
Thy crowd out of normal cells and take
more blood supply and nutrients of other cell.
• Metastasis;
Cancer cells can also break free from tumour
and travel to other parts of the body, to create
more tumours.

8. 3 key suppresser genes
• Events in G1 phase are critical for
carcinogenesis.
• Three protein RB1, TP53, CDK’s
-Central role in the progression through G1,
-Somatic mutation cause genetic changes in
tumour,
-Inherited mutation cause familiar cancer
syndrome.

9. PRB regulation of progression through
G1……….
• Express and helps control cycling of all cell.
• The gene product, PRB is 110KD,
• Some cells contain related protein pi07 and p130
• Loss of RB caused special type of cancer.
• P53 is the guardian of the genome,
• It is encoded by TP53
• Absence of p53 caused tumour or replicate
damaged DNA, or no apoptosis.

10. Classification
• Carcinoma is a type of cancer that starts in
cells that make up the skin or the tissue lining
organs, such as the liver or kidneys.

11. • Sarcoma is a cancer that arises from
transformed cells of mesenchymal origin. Thus,
malignant tumours made in bone, cartilage, fat,
muscle, vascular, or hematopoietic tissues .

12. • Lymphoma is cancer of a group of blood cell
tumours that develop from lymphocytes. Signs
and symptoms may include
enlarged lymph nodes, fever, weight loss and
constantly feeling tired and others.

13. • Leukaemia is cancer of the blood cells. It
starts in the bone marrow, the soft tissue inside
most bones. Bone marrow is where blood cells
are made.

14. Carcinogens
• Carcinogens are substances and agent that cause
cancer.
Alcohol
• Primary cause of liver cancer.
• Also mouth , oesophagus and other cancers.
Tobacco
• 30% of all cancer death.
• 87% of all lung cancer caused due to smoking.
• Also cause cancer of mouth,stomach,nasal
cavity, kidney, pancreas, esopagus and bladder.

15. Continuous……
Ultraviolet lights
• Primary cause of skin cancer.

16. Cancer Prevention
2/3 of all cancers may be prevented by
• Avoiding tobacco
• Avoiding/limiting alcohol Consumption
• Eating adequate fruits and vegetables daily
• Knowing family history of cancer
• Limiting exposure sun/radiation
• Choosing healthy food reduces cancer risk by 30 –
40%
• Eating a low fat diet
• Regular exercising
• Maintaining healthy weight throughout life