Carcinogenesis: The Molecular Basis Of Cancer

1. General

   1. Non-lethal genetic damage—MUTATION—lies at the heart of carcinogenesis

   2. How mutation occurs

      1. Environmental agents

         1. chemicals

         2. radiation

         3. viruses

      2. Inherited

         1. Genetic basis

            1. tumor is clonal expansion of single progenitor cell that has incurred genetic damage

            2. in other words, TUMORS ARE MONOCLONAL

   3. Targets of genetic damage

      1. Growth promoting proto-oncogenes

         1. mutant alleles are considered dominant

         2. transform cells despite normal counterpart

         3. only need one mutant allele to develop cancer

      2. Growth inhibiting cancer suppressor genes—anti-oncogenes

         1. also known as recessive oncogenes

         2. both normal alleles must be damaged to develop cancer

      3. Genes that regulate apoptosis

         1. may be dominant or recessive

      4. Genes that regulate repair of damaged DNA

         1. cell is not able to repair non-lethal damage to DNA

            1. ex. XP

   4. Carcinogenesis is a MUTLI-STEP PROCESS at both the genetic and phenotypic level that results in tumor progression

Category: Pathology Notes