1. Cancer A power point presentation by Mr. C 2005

2. Carcinogenesis – The Development of Cancer

10. Mitosis gone mad…

11. Oncogene initiation

12. Generation of oncogene by radiation

15. THE FOUR BASIC CHARACTERISTICS OF CANCER CELLS • The cells of the cancer, at least at its beginning, must have been derived from a single cell that went wrong. • The cell must have independent ability to divide continuously and out of control. • The cell must be able to separate from its neighbouring cells and move to a new location where a new mass of cells will develop. • When a cancer cell divides, it often results in a cell with an abnormal number of chromosomes, either more or less than the normal complement. This characteristic varies strongly with the type of cancer. In some cancers, the cell divisions are perfectly normal.

16. THE SEVEN DANGER SIGNS OF CANCER • 1. A change in bowel or bladder habits. • 2. A sore that doesn'theal. • 3. Unusual bleeding or discharge. • 4. A thickening lump in the breast or elsewhere in the body. • 5. Indigestion or difficulty in swallowing. • 6. Obvious changes in a wart or mole. • 7. A persistent nagging cough or hoarseness.

17. Ways to memorize signs • Cough C • Change Climbs • Lump • Indigestion • Mole • Bleeding • Sore

18. Review of Carcinogenesis – The Development of a Cancer • 1) INITIATION • a chemical (e.g. cigarette smoke, asbestos, benzene, DDT) or radiation (e.g. U.V. light, X-rays, gamma rays) mutagen causes a mutation in DNA that turns a protooncogene into an oncogene. • The mutagen that does this is called an INITIATOR.

19. 2) PROMOTION • Exposure to a promoterafter initiation will speed up the development of cancer. • e.g. a promoter could be cigarette smoke, U.V. light, a high fat/low fiber diet. • Promoters trigger uncontrolled growth.

20. 3) TUMOR DEVELOPMENT • uncontrolled growth of cancerous cells. (a new growth of cancerous cells is called a neoplasia). • a primary tumor forms. • the cells of the tumor are undifferentiated and resemble embryonic cells (this property of cancer cells is called anaplasia). • the tumor cells release chemicals that cause increased vascularization of the tumor (i.e. more blood vessels grow towards the tumor). The tumor cells release proteases that allow the tumor to grow into surrounding tissue.

21. METASTASIS • Tumor cells acquire the ability to break free from the primary tumor and invade blood vessels or lymph vessels. • These cells travel in the blood or lymph, and go to other sites in the body, where they leave the blood or lymph and grow into new tumors (called secondary tumors) • Cancer at this stage is very difficult to treat effectively.