Prerequisite Genetic Traits for Metastasis

The genetic and epigenetic abnormalities in tumors influence the metastatic traits of disseminated cells by activation of oncogenes and inactivation of tumor-suppressor genes. Tumor-suppressor genes affect genome stability, cancer-cell survival and growth while also being involved in the response and repair of DNA. They are a part of the prerequisites for metastasis and determine initiation and continuous development of the oncogenic process resulting in unrestricted proliferation and resistance to cell death signals. Inactivation of tumor suppressor genes can occur through various mechanisms such as loss of heterozygosity and chromosomal damage as well as by genetic mutations and epigenetic mechanisms such as promoter hypermethylation (Nguyen and Massague 2007; Eccles 2005). The amplification and mutation of oncogenes in primary tumors, together with the selective pressures of the tumor microenvironment play a key role in the formation of metastasis (Bernards and Weinberg 2002).