Cancer genetics

INTRODUCTION
HISTORY
GENES INVOLVED IN CANCER
ONCOGENES
TUMOUR SUPPRESSOR GENES
ONCOGENE
INTRODUCTION
TYPES
ACTIVATION OF PROTO ONCOGENES
FUNCTION
TUMOUR SUPPRESSOR GENES
INTRODUCTION
EXAMPLE
RB GENE
TP53 GENE
CONCLUSION
REFERENCES

1.   CANCER GENETICS   . By KAUSHAL KUMAR SAHU Assistant Professor (Ad Hoc) Department of Biotechnology Govt. Digvijay Autonomous P. G. College Raj-Nandgaon ( C. G. )

2. SYNOPSIS INTRODUCTION HISTORY GENES INVOLVED IN CANCER ONCOGENES TUMOUR SUPPRESSOR GENES ONCOGENE INTRODUCTION TYPES ACTIVATION OF PROTO ONCOGENES FUNCTION

3. TUMOUR SUPPRESSOR GENES INTRODUCTION EXAMPLE RB GENE TP53 GENE CONCLUSION REFERENCES

4. INTRODUCTION CANCER Cancer is a group of disease that involve uncontrolled division of cells. It is due to failure of the mechanism that usually control the growth and proliferation of cells.

5. Cancer arises from a single cell which has undergone mutation. TUMOUR is a cluster of cells resulting from rapid cell growth Cancer genetics deals with the study of genes involve in causing cancer. Most or all cause of cancer are genetic damage .

6. HISTORY 1890- HANSEMANN -abnormal behaviour of chromosome in cancer cell. 1911- PEYTON ROUS -a virus can cause cancer when injected into a suitable host animal 1976- Dr.J.MICHAEL BISHOP and HAROLD E. VARMUS oncogenes were defective proto-oncogenes.

7. GENES INVOLVED IN CANCER ONCO GENES TUMOUR SUPRRESSOR GENES

8. 1) ONCOGENES The word ONCO comes from a Greek word onkos – bulk or mass Any gene that encodes a protein able to transform cells in culture or to induce cancer in animal. Oncogene encode protein that promote the loss of growth control and conversion of a cell to a malignant state.

9. TYPES Cellular or c- oncogene -present in host cell and carry out all the necessary function of the host cell . Viral or v- oncogene - derived by capturing a proto-oncogene from a host genome.

10. ACTIVATION OF PROTO-ONCOGENES TO ONCOGENES .

11. Mechanism of activation MUTATION GENE DUPLICATION CHROMOSOME REARRANGEMENT

12. Fig;-mutation in oncogene

13. Fig;-Types of protein encoded by oncogene. FUNCTION

14. Oncogenes That Encode Growth Factors Cancer-causing simian sarcoma virus contained an oncogene ( sis ) derived from the cellular gene for platelet-derived growth factor (PDGF), a protein present in human blood. Cultured cells that are transformed with this virus secrete large amounts of PDGF into the medium, which causes the cells to proliferate in an uncontrolled fashion.

15. 2. Oncogenes That Encode Growth Factors Receptors(GFR) Malignant cells contain a much larger number of the receptors which makes the cells sensitive to much lower concentrations of the growth factor. Proto-oncogene encode GFR can also activated by mutation that cause the receptor monomer to undergo dimerization in the absence of exogenous ligand, which leads to their protein kinase activity .

16. 3.Oncogenes That Encode Cytoplasmic Protein Kinases

17. 4. Oncogenes That Encode Nuclear Transcription Factors Cells that are not actively growing and dividing tend to withdraw from the cell cycle and enter to G0,stage. Myc is one of the first proteins to appear when a cell in this quiescent stage has been stimulated by growth factors to renters the cell cycle and divide.

18. 5.Oncogenes That Encode Products That Affect Apoptosis

19. 2 ) TUMOUR SUPPRESSOR GENES (TSG ) TSG inhibit cell proliferation by arresting progression through the cell cycle. Protein encoded by TSG act as negative regulation of cell proliferation . Their elimination promotes uncontrolled cell growth

20. Fig;-Mutation in TSG

21. EXAMPLE 1) RB GENE This gene responsible for RETINOBLASTOMA cancer of retina of eye .. -

22. Retinoblastoma is inherited . Retinoblastoma requires both copies of the RB gene either mutated or eliminated. 1)SPORADIC 2)FAMILIAL

23. Fig:- pRB in controlling transcription of genes required for progression of the cell cycle.  

24. 2) TP53 GENE   TP53 is a TSG that when absent is responsible for a rare disorder called Li- Fraumeni syndrome. Inherit one normal and one abnormal (or deleted) allele of the TP53 tumour-suppressor gene. Function of p53 p53 is a transcription factor that activates the expression of genes involved in cell cycle regulation and apoptosis .

25. Fig;-Function of p53

26. The Role of p53: p53 is a transcription factor that activates the expression of either- p21 gene, whose product cause cell arrest or, Bax gene, whose product cause apoptosis . genetic damage, as occurs if the cell is subjected to ultraviolet light or chemical carcinogens, the concentration of p53 rises rapidly. p53 degradation is facilitated by a protein called MDM2.

27. fig;-Role of p53 in regulation of cell cycle

28. conclusion

29. S. No. BOOKS AUTHOR 1. Cell and molecular biology Gerald karp 2. Molecular cell biology Lodish 3. Molecular biology of cancer F. Macdonald and C.H.J. Ford 4. Internet www.kbiotech.com 5. Internet www.genetics.edu.au References