MTHFR-1298 A>C (rs1801131) is a predictor of survival in two cohorts of stage II/III colorectal cancer patients treated with adjuvant fluoropyrimidine chemotherapy with or without oxaliplatin.

Adjuvant treatment based on fluoropyrimidines (FL) improves the prognosis of stage II/III colorectal cancer (CRC). Validated predictive/prognostic biomarkers would spare therapy-related morbidity in patients with a good prognosis. We compared the impact of a set of 22 FL-related polymorphisms with the prognosis of two cohorts of CRC patients treated with adjuvant FL with or without OXA, including a total of 262 cases. 5,10-Methylentetrahydrofolate reductase (MTHFR) MTHFR-1298 A>C (rs1801131) polymorphism had a concordant effect: MTHFR-rs1801131-1298CC genotype carriers had a worse disease free survival (DFS) in both the cohorts. In the pooled population MTHFR-rs1801131-1298CC carriers had also a worse overall survival. We computed a clinical score related to DFS including MTHFR-rs1801131, tumor stage, sex and tumor location, where rs1801131 is the most detrimental factor (hazard ratio=5.3, 95% confidence interval=2.2-12.9; P-value=0.0006). MTHFR-rs1801131 is a prognostic factor that could be used as an additional criteria for the choice of the proper adjuvant regimen in stage II/III colorectal cancer patients.

A prospective validation pharmacogenomic study in the adjuvant setting of colorectal cancer patients treated with the 5-fluorouracil/leucovorin/oxaliplatin (FOLFOX4) regimen.

The discovery of pharmacogenomic markers in colorectal cancer (CRC) could be setting-specific. FOLFOX4 is employed in the adjuvant and metastatic setting in CRC. This prospective study is aimed to validate in the adjuvant setting the pharmacogenomic markers of toxicity reported in the metastatic setting (that is, GSTP1-rs947894, and -rs1138272; GSTM1-null genotype; AGXT-rs4426527, -rs34116584 and del-74 bp), and to discover additional markers. CRC patients (n=144) treated with adjuvant FOLFOX4 were genotyped for 57 polymorphisms in 29 genes. Grade ≥ 2 neurotoxicity was associated (false discovery rate-adjusted q-value <0.1) with single-nucleotide polymorphisms in ABCC1 (rs2074087: odds ratio=0.43(0.22-0.86)), and ABCC2 (rs3740066: 2.99(1.16-7.70); rs1885301: 3.06(1.35-6.92); rs4148396: 4.69(1.60-13.74); rs717620: 14.39(1.63-127.02)). hMSH6-rs3136228 was associated with grade 3-4 neutropenia (3.23(1.38-7.57), q-value=0.0937). XRCC3-rs1799794 was associated with grade 3-4 non-hematological toxicity (8.90(2.48-31.97), q-value=0.0150). The markers previously identified in metastatic CRC were not validated. We have identified new markers of toxicity in genes of transport and DNA repair. If validated in other studies, they could help to identify patients at risk of toxicity.

Nucleotide excision repair gene variants and association with survival in osteosarcoma patients treated with neoadjuvant chemotherapy.

The aim of this study was to investigate the role of common polymorphisms in the nucleotide excision repair pathway genes in the tumorigenesis of osteosarcoma and in the response to DNA damaging therapies, such as cisplatin-based neoadjuvant therapy. Excision repair cross-complementing (ERCC) group 2 (XPD; rs13181 and rs1799793), group 5 (XPG; rs17655) and group 1 (XPA; rs3212986 and rs11615) polymorphisms were analyzed in a group of 130 homogenously treated patients with high-grade osteosarcoma, for association with event-free survival (EFS), using the Kaplan-Meier plots and log-rank test. A positive association was observed between both XPD single-nucleotide polymorphisms and an increased EFS (hazards ratio (HR) = 0.34, 95% confidence interval (CI) 0.12-0.98 and HR = 0.19, 95% CI 0.05-0.77, respectively). We had also performed a case-control study for relative risk to develop osteosarcoma. Patients carrying at least one variant allele of XPD rs1799793 had a reduced risk of developing osteosarcoma, compared with wild-type patients (odds ratio = 0.55, 95% CI 0.36-0.84). This study suggests that XPD rs1799793 could be a marker of osteosarcoma associated with features conferring either a better prognosis or a better outcome after platinum therapy, or both.