Genetic Basis For Acute Lymphoblastic Leukemia Drug Toxicity Identified Interview with:
Jun J. Yang  Ph.D.

Assistant Member Dept. of Pharm. Sci.
St. Jude Children’s Research Hospital
Memphis, TN 38105

Medical Research: What is the background for this study? What are the main findings?

Dr. Yang: Mercaptopurine is highly effective in acute lymphoblastic leukemia (ALL) and essential for the cure of this aggressive cancer. However, it also has a narrow therapeutic index with common toxicities. Identifying genetic risk factors for mercaptopurine toxicity will help us better understand how this drug works and also potentially enable clinicians to individualize therapy based on patients’ genetic make-up (precision medicine).

In addition to confirming the role of TPMT, we have identified another important genetic risk factor (a genetic variation in a gene called NUDT15) for mercaptopurine intolerance. Patients carrying the variant version of NUDT15 are exquisitely sensitive and required up to 90% reduction of the normal dose of this drug. TPMT variants are more common in individuals of African and European ancestry, whereas NUDT15 variants are important in East Asians and Hispanics.

Medical Research: What should clinicians and patients take away from your report?

Dr. Yang: There is clearly a genetic basis for mercaptopurine toxicity. For example, patients carrying variant versions of TPMT and NUDT15 are at much higher risk of experiencing excessive toxicities from mercaptopurine therapy.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Yang: The  genetic basis of mercaptopurine response (or response to any drugs) is complex involving many genes. Continued research in this area (pharmacogenomics) is likely to reveal critical knowledge with potential clinical relevance. Also, racial and ethnic diversity is an important consideration for future research of pharmacogenomics on a global scale.


J Clin Oncol. 2015 Jan 26. pii: JCO.2014.59.4671. [Epub ahead of print]

Inherited NUDT15 Variant Is a Genetic Determinant of Mercaptopurine Intolerance in Children With Acute Lymphoblastic Leukemia.

Yang JJ1, Landier W2, Yang W2, Liu C2, Hageman L2, Cheng C2, Pei D2, Chen Y2, Crews KR2, Kornegay N2, Wong FL2, Evans WE2, Pui CH2, Bhatia S2, Relling MV2.

[wysija_form id=”1″] Interview with Jun J. Yang Ph.D. (2015). Genetic Basis For Acute Lymphoblastic Leukemia Drug Toxicity Identified