Correlation between clinical response to sorafenib in hepatocellular carcinoma treatment and polymorphisms of P-glycoprotein (ABCB1) and of breast cancer resistance protein (ABCG2): monocentric study.

OBJECTIVES: We studied the relation between the polymorphism of P-glycoprotein (P-gp) and of breast cancer resistance protein (BCRP), encoded by ABCB1 and ABCG2 genes, respectively, and the pharmacokinetic variability and clinical response during the treatment with sorafenib of hepatocellular carcinoma. METHODS: At the Paul Brousse Hospital in Villejuif, France, 47 consecutive patients with advanced HCC treated with a single agent sorafenib, were enrolled. Sorafenib exposure was measured by its plasma concentration 3 h after oral administration of 400 mg (bid) by liquid chromatography. All enrolled patients were genotyped for ABCB1 (rs2032582; rs1045642) and ABCG2 (rs2231137; rs2231142; rs2622604) by blood genomic DNA extraction and Mass ARRAY genotyping. The clinical response was evaluated after 3months of treatment according to the RECIST criteria. KEY FINDINGS: Significant associations between sorafenib exposure and the studied polymorphisms were observed for ABCB1 3435C>T, ABCG2 34G>A, ABCG2 1143C>T and ABCG2 421C>A, but not for ABCB1 2677G>TA SNP. In heterozygous patients for ABCB1 3435 C>T, ABCG2 34 G>A and ABCG2 1143 C>T polymorphisms were significantly associated with the lowest sorafenib plasma levels. Those patients presented a tendency to have the best clinical evolution. CONCLUSION: Heterozygous forms of the studied polymorphisms could be associated with a better therapeutic response.