Distinct predictive impact of FISH abnormality in proteasome inhibitors and immunomodulatory agents response: redefining high‐risk multiple myeloma in Asian patients

For risk‐adaptive therapeutic approaches in multiple myeloma (MM) treatment, we analyzed treatment outcome according to in situ hybridization (FISH) profiles to investigate the prognostic and predictive values of structural variations in a large series of Asian population. A total of 565 newly diagnosed patients with multiple myeloma between January 2005 and June 2015 were evaluated. FISH results showed del(17p13) in 8.8% (29/331), del(13q14) in 35.5% (184/519), t(14;16) in 2.5% (8/326), t(4;14) in 27.9% (109/390), IgH rearrangement in 47.7% (248/520), and +1q21 in 40.8% (211/517). The presence of del(17p13), IgH rearrangement, and t(14;16) was associated with worse overall survival. Interestingly, however, the presence of t(4;14) conferred little prognostic impact. Treatment‐specific analysis revealed the presence of del(17p13), t(14;16), IgH rearrangement, and trisomy 1q21 was predictive of unsatisfactory response to bortezomib. On the other hand, patients with del(13q14) and del(9p21) were less likely to benefit from lenalidomide. Autologous stem cell transplantation (autoSCT) was less effective in patients with del(17p13), t(14;16), and trisomy 1q21. Predictive values of del(17p13) and t(14;16) to bortezomib and autoSCT are seemingly universal, but predictive marker del(13q14) and del(9p21) for lenalidomide response appears ethnicity‐specific. Thus, FISH profiles in MM treatment should be interpreted with regards to patient's ethnicity.