Although trastuzumab-induced cardiotoxicity is an important determinant to limit the use of this drug, the molecular mechanism of risk for this toxicity is not well understood. To identify a genetic marker(s) determining the risk of trastuzumab-induced cardiotoxicity, we performed whole exome sequencing of germline DNA samples from 9 patients with trastuzumab-induced cardiotoxicity, and conducted a case-control association study of 2,258 genetic variants between 9 cases (with trastuzumab-induced cardiotoxicity) and general Japanese population controls registered in Human Genetic Variation Database (HGVD). To further validate the result of the screening study, we carried out a replication study of 10 variants showing Pmin < 0.001 in the screening study using 234 independent patients treated with trastuzumab, including 10 cases and 224 controls (without trastuzumab-induced cardiotoxicity). In the replication study, we observed that three variants had effect in the same direction as in the screening study (SNV1 in exon 2 of HERADR1, SNV2 in exon 2 of HERADR2 and SNV3 in exon 44 of HERADR3). A combined result of the screening and the replication studies suggested an association of a locus on chromosome 6q12 with trastuzumab-induced cardiotoxicity (SNV3 in HERADR3, combined-Pmin = 0.00056, OR = 13.73). This finding provides new insights into personalized trastuzumab therapy for the patients with HER2 positive cancer.

Citation Format: Chihiro Udagawa, Hiromi Nakamura, Hiroshi Ohnishi, Kenji Tamura, Tatsunori Shimoi, Masayuki Yoshida, Teruhiko Yoshida, Hiroshi Okamura, Yasushi Totoki, Tatsuhiro Shibata, Hitoshi Zembutsu. Whole exome sequencing to identify genetic markers for trastuzumab-induced cardiotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3887.