Alterations in different kinds of Genes cause Cancer Oncogenes dominant gain-of-function mutations promote cell transformation Tumor suppressor genes recessive, loss-of-function mutations promote cell transformation Mutator genes Usually recessive, loss-of-function mutations that increase spontaneous and environmentally induced mutation ratesAlterations in different kinds of Genes cause Cancer Oncogenes dominant gain-of-function mutations promote cell transformation Tumor suppressor genes recessive, loss-of-function mutations promote cell transformation Mutator genes Usually recessive, loss-of-function mutations that increase spontaneous and environmentally induced mutation rates