A Genome-Wide Association Study Identifies Five Novel Genetic Markers for Trastuzumab-Induced Cardiotoxicity in Japanese Population.

Trastuzumab has been administered to patients with HER2-positive cancer, however, the cardiotoxicity is identified as one of the life-threatening toxicities. Clinically useful biomarker for trastuzumab-induced cardiotoxicity has been expected to be developed. To identify a novel genetic marker(s) determining the risk of trastuzumab-induced cardiotoxicity, we performed a first genome-wide association study (GWAS) in Japanese population. We enrolled 481 patients who had been treated with trastuzumab and carried out a GWAS using 11 cases (with cardiotoxicity) and 257 controls (without cardiotoxicity). Top 100 single nucleotide polymorphisms (SNPs) which revealed the smallest P values in GWAS (P = 7.60 x 10(-7) - 2.01 x 10(-4)) were further examined using replication samples consisted of 14 cases and 199 controls. The combined analysis of the GWAS and replication study indicated possible association of five loci with trastuzumab-induced cardiotoxicity (rs9316695 on chromosome 13q14.3, rs28415722 on chromosome 15q26.3, rs7406710 on chromosome 17q25.3, rs11932853 on chromosome 4q25, and rs8032978 on chromosome 15q26.3, P-combined = 6.00 x 10(-6), 8.88 x 10(-5), 1.07 x 10(-4), 1.42 x 10(-4), 1.60 x 10(-4), respectively). Furthermore, we developed a risk prediction model for trastuzumab-induced cardiotoxicity using the five marker SNPs. The incidence of trastuzumab-induced cardiotoxicity in patients with risk score >= 5 was significantly higher (42.5%) compared to that in patients with score <= 4 (1.8%) (P = 7.82 x 10(-15), odds ratio = 40.0). These findings suggest the potential to improve the ability of physicians to avoid the trastuzumab-induced cardiotoxicity for patients with HER2-positive cancer.