Screening of Novel Pharmacogenetic Candidates for Mercaptopurine-Induced Toxicity in Patients With Acute Lymphoblastic Leukemia

• Main Authors: Minyuan Cao, Dandan Yin, Yun Qin, Fei Liao, Yali Su, Xuyang Xia, Ju Gao, Yiping Zhu, Wei Zhang, Yang Shu, Xiaoxi Lu
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2020-03-01
• Series: Frontiers in Pharmacology
• Subjects: mercaptopurine; leukopenia; hepatoxicity; adverse drug reaction; pharmacogenetics; CYP2A7
• Online Access: https://www.frontiersin.org/article/10.3389/fphar.2020.00267/full

A small proportion of patients with acute lymphoblastic leukemia (ALL) may experience severe leukopenia after treating with 6-mercaptopurine (6MP), which can be largely explained by germline variants in TPMT and NUDT15. However, a minority of patients who suffered such adverse drug reaction have NUDT15wt/wtTPMTwt/wt genotype, indicating that other genetic factors may take part in. In this study, we genotyped 539 exon-located nonsilent pharmacogenetic variants in genes involved in phase I/II of drug metabolism in 173 pediatric patients with ALL and conducted association screening for 6MP-induced leukopenia. Besides NUDT15 (rs116855232, P = 6.4 × 10−11) and TPMT (rs1142345, P = 0.003), a novel variant was identified in CYP2A7 gene (i.e., rs73032311, P = 0.0007), which is independent of NUDT15/TPMT variant. In addition, a variant (i.e., rs4680) in COMT is significantly associated with 6MP-induced hepatotoxicity (P = 0.007). In conclusion, variants in CYP2A7 and COMT may be considered as novel potential pharmacogenetic markers for 6MP-induced toxicities, but additional independent validations with large sample size and investigations on related mechanisms are further needed.