Effect of DPYD, MTHFR, ABCB1, XRCC1, ERCC1 and GSTP1 on chemotherapy related toxicity in colorectal carcinoma.

ABCB1, DPYD, MHTFR, XRCC1, ERCC1, GSTP1 and UGT1A1 genetic variants affect proteins related to CRC chemotherapy toxicity. A retrospective cohort study was conducted in 194 CRC patients. In first line treatment, DPYD rs17376848 AG genotype was associated with hematological toxicity (OR = 4.85; p = 0.03); GSTP1 G-allele (OR = 3.01; p = 0.005) and MTHFR rs1801133 T allele (OR = 2.51; p = 0.03) with respiratory toxicity; GSTP1 G-allele with cardiovascular toxicity (OR = 4.05; p = 0.01); ERCC1 rs11615 GG genotype with neurological toxicity (OR = 3.98; p = 0.01) and with asthenia (OR = 2.91; p = 0.08); XRCC1 rs1799782 T allele (OR = 0.31; p = 0.03) and GSTP1 G-allele (OR = 1.81; p = 0.01) with cutaneous toxicity. In second line treatment, XRCC1 rs1799782 T-allele was associated with asthenia (OR = 0.17; p = 0.03) and XRCC1 rs25487 T-allele with gastrointestinal toxicity (OR = 3.03; p = 0.005). After stratifying by treatment, in the 5-Fluorouracil group, the DPYD rs17376848 AG genotype was associated with hematological toxicity (OR = 2.76; p = 0.003), ABCB1 rs1045642 T-allele with the need of treatment adjustment due to toxicity (OR = 3.06; p = 0.01), and rs1045642 CC genotype with gastrointestinal toxicity (OR = 5.80; p = 0.03). In the capecitabine group, the MTHFR rs1801131 CC genotype was associated with asthenia (OR = 3.48; p = 0.009). In the oxaliplatin group, rs1045642 TT genotype was associated with the need to adjust treatment (OR = 0.32; p = 0.02), ERCC1 rs11615 GG genotype with asthenia (OR = 3.01; p = 0.01) and rs1615 GSTP1 GG genotype with respiratory toxicity (OR = 5.07; p = 0.009). ABCB1 rs1045642 T-allele reduces the need for treatment modification with both 5FU and oxaliplatin. Although several biomarkers predicted different toxic effects, they cannot be considered as risk factors for severe toxicity.