Cancer

1. Cancer

2. Regulation of Cell Division • Two sets of genes control cell division. • Proto-oncogenes. • Code for proteins that promote the cell cycle and prevent cell death. • Tumor suppressor genes. • Code for proteins that stop the cell cycle and promote cell death.

5. Replicative Potential • After cells become fully differentiated they can no longer divide. • Chromosomes in human cells end with repetitive DNA sequences, telomeres. • Telomeres get shorter after each cell cycle.

6. Cancer Cells • Carcinogenesis - Development of cancer. • Cancer is a genetic disease requiring at least ten mutations, each propelling cells toward tumor development. • Each tumor is composed of cells that are experiencing uncontrolled growth. • Cancer cells are nonspecialized and do not contribute to body functioning.

9. Cancer Cell Characteristics • Genetically unstable. • Not differentiated - Do not adhere to other cells. • Insensitive to inhibitory growth signals. • No apoptosis (cell death) when DNA repair fails. • Unlimited number of cell cycles. • Induce and sustain angiogenesis (formation of new blood vessels – get O2 to middle of tumor). • Invade and metastasize.

10. Regulation of Cell Cycle • Approximately 100 oncogenes (cancer-causing genes) discovered that can cause increased cell growth and lead to tumors. • Most frequent are in Ras gene family (proteins that promote mitosis & cell division). • Cancer cells no longer respond to inhibitory growth factors (factors that STOP division). • Tumor suppressor genes undergo mutations. • Approximately half-dozen identified.

11. Faces of Cancer:1 in 3 people will develop cancer25% of them will die from cancer