Cellular Aspects of Cancer

General Information Derangements in the cell cycle --> uncontrolled cell division --> tumor growth Links between cell cycle and cancer: more and more discovered all of the time Codes for a protein that turns on the production of another protein that blocks cdk2 and other cdk's, particularly affecting cyclin D1 interaction with these cdk's. Therefore if a tumor supressor (p53) malfunctions this could lead to tumor progression. In general Cancer --> loss of regulated cell growth Cancer cells are monoclonal, derived from cells that have undergon neoplastic transformation Characteristics of cancer cells vascularized (develop own blood supply) invasive (secrete degradatory enzymes) invade surrounding tissue metastasize (cells dislodge from origional tumor and establish new tumors at far away sites) Classification of tumors Carcinoma: epithelial tissue Sarcoma: connective tissue "blast" suffix refers to stem cells Causes of neoblastic transformation Gene translocation EX: Philly chromosome: piece of chromosome 22 transfers to chromosome 9) Viruses especially retroviruses: RNA --> DNA inserts in host cell genome Environmental carcinogens (50 - 90%) of all human cncers most require conversion of procarcinogen --> ultimate carcinogen act by producing genetic mutations In order to actually cause cancer any of the above must be in areas of the genome that affect the cell cycle Genetic basis of Neoplasia Oncogenes src, myc, ras (c - src, c - myc, c - ras) all have been associated with cancers and all have potential roles in the control of the cell cycle Dosage effect Gene mutation Tumor suppressor genes rbl p53 apc