This document discusses cancer genetics and diagnosis. It begins by defining cancer and tumors, explaining that cancer is characterized by uncontrolled cell growth that causes malignant tumors. It then explains that cancer arises from mutations in DNA, particularly in cancer genes like tumor suppressor genes and oncogenes. Tumor suppressor genes normally prevent cell growth but mutations cause loss of function, while oncogenes promote cell growth but mutations result in constant activity. Some cancers are caused by viruses like HPV. Cancer diagnosis is usually based on finding lumps or masses, not genetics. Treatments include surgery, radiation, chemotherapy, anti-angiogenesis drugs, and differentiation therapies.

1. Cancer Genetics and
Diagnosis
Kishan Sharma
M.Sc. 2nd Year
Biotechnology
Manipal University
Jaipur

2. Cancer
Disease characterized by uncontrolled cell growth.
This causes tumors.
 Tumors may be benign or malignant.
 Benign tumors grow in size but do not invade and destroy surrounding
tissue.
Cancer usually means malignant.
Malignancy means a cell is invasive.
Invasion destroys
The internal cellular order of a tissue.
Membranes and barriers that define organs.

3. Cancer
 All cancers derive from single cells that have acquired the
characteristics of continually dividing in an unrestrained manner
and invading surrounding tissues.
 Cancer cells behave in this abnormal manner because of changes
in the DNA sequence of genes, which are known as cancer genes.

4. Mutation
• Germline mutation
– A change in the DNA sequence that can be inherited from
either parent.
• Somatic mutation
– A change in the DNA sequence in cells other than sperm or
egg.
– The mutation is present in the cancer cell and its offspring, but
not in the patient’s healthy cells.

5. Mutations & cancer genes
 Mutations in cancer genes can occur somatically or can be
inherited.
 Mutations in some cancer genes can be inherited from parents, in
which case they are present in every cell of the body. Such people
are at a higher risk of developing cancer.
 Somatic mutations can occur in any of the cells of the body except
the germ cells (sperm and egg) and therefore are not passed on
to children.

6. Cancer genes
 There are two types of cancer genes:
 Tumor suppressor genes
 Oncogenes

7. Cancer genes
 Tumor suppressor genes :
 These genes normally function to prevent cell growth/division.
 They can halt the cell growth cycle to stop unnecessary division or
promote cell death if the cell’s DNA is damaged.
 When this gene mutates to cause a loss in its function, the cell can
progress to cancer, usually in combination with other genetic changes.
 Retinoblastoma (cancer of retina) caused by losing function of RB gene.

8. Cancer genes
 Oncogenes:
 Genes which normally function to promote cell growth/division in
a controlled manner.
 Proto-oncogenes code for proteins that drive cell division.
 When these genes acquire mutations that result in continually
active proteins they become oncogenes and cause uncontrolled
cell growth and division.

9. Viruses Are Associated with Some Cancers
 Viruses are responsible for a number of cancers in animals, humans.
 For example, about 95% of all women with cervical cancer are infected
with human papilloma viruses (HPVs).
 Human papilloma virus causes benign tumors of epithelial cells.
 70% of the cases of cervical cancer are caused by HPV-16 and HPV-18.

10. Colorectal Cancer Arises Through the Sequential
Mutation of a Number of Genes

11. Hereditary Breast/Ovarian Cancer
 BRCA1 and BRCA2 genes.
 Associated with defective DNA repair complex that repairs breaks and
cross-links in DNA.

12. Cancer Diagnosis
 Because cancer is caused by many different genes diagnosis
is not genetic.
 Usually diagnosed after finding a lump ,either feeling it or
visualizing it on MRI.
 Labelled by tissue where cancer begin.

13. Cancer Treatments
 Surgery – Removal of tumor and removal of susceptible
tissue.
 Radiation and Chemotherapy – Kill off cells that are rapidly
dividing.
 Treat specific form of cancer present.
 Prevent angiogenesis: –Stop tumor from vascular growth,
however, stops all vascular growth.
 Promote cells to differentiate: –try to coax cells back to
original cell type.

14. Thank You