Retroviral oncogenes
Cellular protooncogenes
Mutation carrying cells with proliferation advantage Activated protooncogene
The p53 gene product protects from propagation of cells that carry damaged DNA
Series of mutations on tumor suppressor genes, repair genes and oncogenes
Metastasis Spread of malignant cells from the primary site of cancer to any other part of the body Main cause of therapy failure Advanced disease stage but also at early stages Secondary sites depend on primary tumor
Blood (and lymphatic) vessels are the highways for metastatic cancer cells
IARC categories of substances regarding carcinogenicity 1. Sufficient evidence of carcinogenicity in humans 2a. Probably a human carcinogen 2b. Possibly a human carcinogen 3. Inadequate evidence of carcinogenicity in humans 4. Not carcinogenic
US - Natl. Toxicology Program categories of carcinogens Part A –Known to be human carcinogens –~40 chemicals or chemical mixtures Part B –Reasonably anticipated to be human carcinogens –>100 chemicals