ALK expression plays different roles in anaplastic large-cell lymphomas and outcome of crizotinib use in relapsed/refractory ALK+ patients in a Chinese population.

The prognostic value of anaplastic lymphoma kinase (ALK) expression in patients with anaplastic large-cell lymphoma (ALCL) remains controversial. Data on the clinical features of ALCL in a Chinese population are limited. We retrospectively reviewed 1293 patients with pathologically diagnosed lymphoma at Guangdong General Hospital from June 2007 through August 2016. We evaluated the incidence of ALCL, clinical characteristics, survival status, and outcome of crizotinib use in four relapsed/refractory ALK-positive patients. Among the 1293 patients, 1193 (92.3%) were non-Hodgkin's lymphoma, and 53 (4.4%) of whom were ALCL. Of the 50 ALCL patients, with a median age of 34 years, were evaluated. Among them, 33 (66.0%) were ALK-positive and 17 (34.0%) were ALK-negative. Significantly, more patients younger than 40 years old were ALK-positive than ALK-negative (66.7 vs. 23.5%; P = 0.003). The 5-year progression-free survival (PFS) for ALK-positive and ALK-negative patients were 61 and 11%, and the 5-year overall survival (OS) were 70 and 22%, respectively. Median PFS and OS were significantly better for patients with ALK-positive than ALK-negative (60.1 vs. 9.4 months, P = 0. 017; not reached vs. 32.7 months, P = 0.021). Multivariate analyses identified ALK expression, stage, and bone marrow involvement as independent prognostic factors for PFS and OS. Four relapsed ALK-positive patients were treated with crizotinib and two died. Our results suggest that ALK expression has different prognostic significance in patients with ALCL. Mechanisms underlying early relapse after chemotherapy and resistance to crizotinib need further investigation.