In this field, our research group has shown that the presence of MSI in sporadic CRC is associated with a reduction in initiation of base excision repair (BER) by the DNA glycosylases OGG1 and MPG, as well a reduction in signaling of DNA single-strand breaks (SSB) repair by PARP1 [85]. The gene discussed is PARP1; the disease is colorectal carcinoma.