Role of DNA mismatch repair genes in lung and head and neck cancer (Review)

The role of the DNA repair mechanism is to protect genetic material from destabilization. A defect in the DNA mismatch repair (MMR) mechanism has been associated with both hereditary and sporadic tumors. The dysregulation of MMR gene expression has been reported in lung, and in head and neck sporadic tumors. However, the mechanisms through which defects in the DNA MMR mechanism promote lung, and head and neck cancer remain unclear. Environmental factors and epigenetic alterations can significantly alter the ability of cells to repair genetic damage. The loss or a low expression of MMR genes allows for the survival of cells carrying a significant amount of genetic alterations, some in proto-oncogenes or genes regulating the cell cycle. The dysregulation or malfunction of the MMR mechanism has also been linked to alterations in response to chemotherapy. The investigation of MMR dysregulations in lung, and head and neck carcinomas may contribute to a better understanding of their biological role in the development and progression of these types of cancer, and may thus also improve their diagnostic, prognostic and therapeutic value.