Cancer: Genetic and chromosomal changes

Cancer occurs as a result of mutations of genes that control normal cell growth and differentiation (protooncogenes). Such genetic damage may be acquired through environment factors (i.e.: radiation, chemicals, viruses) or genetic factors (family tree). Thus, the acquisition of genetic malproducts causes cancers. Thus, morphological and biochemical changes seen in cells is as a result of these genetic mutations.

The principal targets of genetic mutations/damage are: 1) protooncogenes, 2) cancer-suppresor genes, 3) apoptotic genes, 4) DNA repair genes.

Carcinogenesis is a multi-step process, known as tumour progression. The phenotypic characteristics expressed by tumour cells are acquired as the tumour progresses (i.e.: first you get excessive growth ===> local invasiveness ===> metastases). The genetic lesions also accumulate as the tumour progresses ===> hence giving rise to the phenotypic characteristics mentioned above.

Category: Pathology Notes