• King Pan Ng, Axel M Hillmer, Charles T H Chuah, Wen Chun Juan, Tun Kiat Ko, Audrey S M Teo, Pramila N Ariyaratne, Naoto Takahashi, Kenichi Sawada, Yao Fei, Sheila Soh, Wah Heng Lee, John W J Huang, John C Allen, Xing Yi Woo, Niranjan Nagarajan, Vikrant Kumar, Anbupalam Thalamuthu, Wan Ting Poh, Ai Leen Ang, Hae Tha Mya, Gee Fung How, Li Yi Yang, Liang Piu Koh, Balram Chowbay, Chia-Tien Chang, Veera S Nadarajan, Wee Joo Chng, Hein Than, Lay Cheng Lim, Yeow Tee Goh, Shenli Zhang, Dianne Poh, Patrick Tan, Ju-Ee Seet, Mei-Kim Ang, Noan-Minh Chau, Quan-Sing Ng, Daniel S W Tan, Manabu Soda, Kazutoshi Isobe, Markus M Nöthen, Tien Y Wong, Atif Shahab, Xiaoan Ruan, Valère Cacheux-Rataboul, Wing-Kin Sung, Eng Huat Tan, Yasushi Yatabe, Hiroyuki Mano, Ross A Soo, Tan Min Chin, Wan-Teck Lim, Yijun Ruan, and S Tiong Ong.
• Cancer & Stem Cell Biology Signature Research Programme, Duke-National University of Singapore Graduate Medical School, Singapore.
• Nat. Med. 2012 Mar 18; 18 (4): 521-8.

AbstractTyrosine kinase inhibitors (TKIs) elicit high response rates among individuals with kinase-driven malignancies, including chronic myeloid leukemia (CML) and epidermal growth factor receptor-mutated non-small-cell lung cancer (EGFR NSCLC). However, the extent and duration of these responses are heterogeneous, suggesting the existence of genetic modifiers affecting an individual's response to TKIs. Using paired-end DNA sequencing, we discovered a common intronic deletion polymorphism in the gene encoding BCL2-like 11 (BIM). BIM is a pro-apoptotic member of the B-cell CLL/lymphoma 2 (BCL2) family of proteins, and its upregulation is required for TKIs to induce apoptosis in kinase-driven cancers. The polymorphism switched BIM splicing from exon 4 to exon 3, which resulted in expression of BIM isoforms lacking the pro-apoptotic BCL2-homology domain 3 (BH3). The polymorphism was sufficient to confer intrinsic TKI resistance in CML and EGFR NSCLC cell lines, but this resistance could be overcome with BH3-mimetic drugs. Notably, individuals with CML and EGFR NSCLC harboring the polymorphism experienced significantly inferior responses to TKIs than did individuals without the polymorphism (P = 0.02 for CML and P = 0.027 for EGFR NSCLC). Our results offer an explanation for the heterogeneity of TKI responses across individuals and suggest the possibility of personalizing therapy with BH3 mimetics to overcome BIM-polymorphism-associated TKI resistance.

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