MRC1 and neoplasm: The specific mechanism that determines this phenomenon is still unclear but it is hypothesized that temozolomide may exert a selective pressure on tumor clones specifically targeting for MMR loss (in particular, MSH6) and that some post-translational changes in the subcellular localization of MMR heterodimers, in response to the alkylating action, may be partly responsible for loss of MMR proteins expression [17].