RESEARCH COMMUNICATION XRCC1-77T>C Polymorphism and Cancer Risk: A Meta- analysis

Certain genetic variants associated with repair of DNA substantially increase the risk of cancer in carriers because of defined biochemical alterations caused by the polymorphisms. Base excision repair (BER) is the predominant DNA damage repair pathway for the processing of small base lesions, derived from oxidation and alkylation damage (Almeidaet al., 2007). One of the most important proteins is X-ray repair crosscomplementation group 1 (XRCC1), a scaffold protein closely associated with BER pathway coordination by interacting with most components of the BER short-patch pathway (Vidalet al., 2001; Campalanset al., 2005; Daset al., 2006). The XRCC1 gene is 33 kb in length, and is located on chromosome 19q13.2-13.3. More than 60 validated single nucleotide polymorphisms in XRCC1 gene are listed in Ensemble database, and most extensively studied are genetic changes Arg194Trp, Arg280His, Arg399Gln and -77T>C (Ginsberget al., 2011). Recently, a variant in the 5’untranslated region (UTR) of XRCC1 (-77 T>C, rs3213245) has been identified, which appeared to lower XRCC1 levels by decreasing gene expression and was shown to be significantly associated with risks of esophageal squamous cell carcinoma and lung cancer in a Chinese population . Mutations of XRCC1 may increase the risk of cancers by impairing the