Rituximab response in follicular lymphoma is associated with the rs20575 polymorphism in TRAILR1 extrinsic apoptosis trigger.

OBJECTIVE: Rituximab in combination with chemotherapy has been proven to increase progression-free and overall survival in follicular lymphoma (FL), but there is considerable interindividual variability in the response. Extrinsic pathway apoptosis triggered by death receptors seems to be involved in the mechanism of action of monoclonal antibodies. This study aimed to assess the association between TRAILR1/TRAIL polymorphisms (rs20575, rs20576, rs2230229, rs12488654) and rituximab response and the relationship with FASL rs763110, previously found to be associated with rituximab response. PATIENTS AND METHODS: Polymorphisms were determined in a study cohort of 125 FL patients treated with rituximab as first-line treatment and correlated with response, which was scored according to the International Working Group Consensus Revised as complete response, partial response, stable disease, and progressive disease. RESULTS: No significant association with response was found for rs20576, rs2230229, and rs12488654 polymorphisms. In contrast, rs20575 GC/GG carriers were more partial/nonresponders (88.2%) than complete responders (72.5%), showing a trend toward statistical significance (P=0.064). In a multivariable setting, we found that female sex [odds ratio=0.355, 95% confidence interval (CI): 0.137-0.922, P=0.033] and the TRAILR1 rs20575 CC genotype (odds ratio=0.162, 95% CI: 0.035-0.757, P=0.021) were independent positive predictive factors of complete clinical response to rituximab, constructing a parsimonious model with good calibration [χ of 5.719 (d.f.=6, P=0.455)] and discrimination (C-statistic=0.739, 95% CI: 0.636-0.842). CONCLUSION: After studying the pharmacogenetic role of TRAILR1/TRAIL polymorphisms in rituximab-treated FL patients, we found that the rs20575 CC genotype is an independent predictive factor of better rituximab response, indicating the possible involvement of death receptors in anti-CD20 mechanisms of action.

Polymorphisms in xenobiotic metabolizing genes (EPHX1, NQO1 and PON1) in lymphoma susceptibility: a case control study.

BACKGROUND: The interplay between genetic susceptibility and carcinogenic exposure is important in the development of haematopoietic malignancies. EPHX1, NQO1 and PON1 are three genes encoding proteins directly involved in the detoxification of potential carcinogens. METHODS: We have studied the prevalence of three functional polymorphisms affecting these genes rs1051740 EPHX1, rs1800566 NQO1 and rs662 PON1 in 215 patients with lymphoma and 214 healthy controls. RESULTS: Genotype frequencies for EPHX and NQO1 polymorphisms did not show any correlation with disease. In contrast, the GG genotype in the PON1 polymorphism was found to be strongly associated with the disease (15.3% vs. 4.7%; OR = 3.7 CI (95%): 1.8-7.7; p < 0.001). According to the pathological diagnosis this association was related to follicular (p = 0.004) and diffuse large B-cell (p = 0.016) lymphomas. CONCLUSIONS: Despite the fact that further confirmation is needed, this study shows that the PON1 GG genotype in rs662 polymorphism could be a risk factor for B-cell lymphomas.