RAS genes in colorectal carcinoma: pathogenesis, testing guidelines and treatment implications

The RAS family is among the most commonly mutated genes in all human malignancies including colon cancer. In normal cells, RAS proteins act as a link in the intracellular signal transduction initiated by binding of growth factors to cell membrane receptors mediating cell survival. RAS isoproteins have great morphological similarities, but despite that, they are thought to have different functions in different tissues. RAS mutations, as supported by several studies including animal models, have a role in the development and progression of colorectal cancer. The detection of RAS mutations in patients with colorectal carcinoma, specifically KRAS and NRAS, has significant clinical implications. It is currently recommended that patients with colon cancer who are considered for antiepidermal growth factor receptor monoclonal antibodies, get RAS mutation testing since only those with wildtype-RAS genes benefit from such treatment. Despite decades of research, there is currently no effective and safe treatment that directly targets RAS-mutated neoplasms. Multiple therapeutic approaches directed against RAS mutations are currently experimental, including a promising immunotherapy study using T-cells in patients with metastatic colon cancer.