Patient with HNPCC (hereditary nonpolyposis colon cancer) has genes with microsatellite instability. This is due to failure of which repair mechanism of DNA: (A) Mismatch repair, (B) Base excision repair, (C) Homologous end joining repair, (D) Non homologous end joining repair
Answer is A. Mismatch repair: It is one of the repair mechanisms in DNA replication. It operates when there is mismatched base paining. For eg: when A pairs with C. This repair mechanism is defective in HNPCC.