OBJECTIVETo investigate the association between ABCB1 polymorphisms and chemosensitivity of paclitaxel in Chinese advanced gastric cancer(AGC) patients.

METHODSClinical data and peripheral blood prior to chemotherapy of 412 AGC patients treated with first-line capecitabine plus paclitaxel(pactitaxel group, n=268) or cisplatin(cisplatin group, n=268) in Peking University Cancer Hospital from December 2008 to April 2013 were retrospectively collected. ABCB1 G2677T/A polymorphisms were determined using PCR amplification and Sanger Sequencing. Clinical response evaluation and survival analysis were performed using RECIST1.1 criteria and Kaplan-Meier curve, respectively. The associations of ABCB1 G2677T/A polymorphisms with clinical response and survival were analyzed statistically.

RESULTSThe genotypes of ABCB1 were detected in all the patients and the frequency of wild type(G2677G), single allele variants(G2677T+G2677A), and two allele variants (T2677T+T2677A+A2677A) was 22.8%(94/412), 49.8%(205/412), and 27.4%(113/412), respectively. In paclitaxel group, the disease control rate(DCR)[89.9%(116/129)] and median progression-free survival(PFS)(190 days) of patients with single allele variants of G2677T/A were significantly higher than those of wild type patients[76.1%(51/67) and 110 days, all P<0.05], and did not differ statistically from those with two allele variants. In cisplatin group, no significant differences were observed among patients with different genotypes of ABCB1 in terms of the DCR or PFS(all P>0.05).

CONCLUSIONSABCB1 G2677T/A polymorphisms are associated with chemosensitivity of paclitaxel in gastric cancer.