Hypoxia-inducible factor-1 α expression predicts superior survival in patients with diffuse large B-cell lymphoma treated with R-CHOP

Purpose: Hypoxia-inducible factor (HIF) controls the expression of genes in response to hypoxia, as well as a wide range of other cellular processes. We previously showed constitutive stabilization of HIF-1α in the majority of patients with diffuse large B-cell lymphoma (DLBCL). To our knowledge, the prognostic significance of HIF in lymphoma has never been investigated. Patients and Methods: We studied the immunohistochemical protein expression of HIF-1α on tissue microarrays from 153 patients with DLBCL treated in sequential cohorts with cyclophosphamide, doxorubicin, oncovin, and prednisone (CHOP) or rituximab-CHOP (R-CHOP) from 1999 to 2002. Results were correlated with patient outcome. Results: Median follow-up for all patients was 80 months. Among all patients, HIF-1α was expressed in 62% of germinal center and 59% of non-germinal center patients. With HIF-1α analyzed as a dependent variable, there were no survival differences in CHOP-treated patients. In the R-CHOP group, however, HIF-1α protein expression correlated with significantly improved progression-free survival (PFS) and overall survival (OS). Five-year PFS for HIF-1α-positive patients was 71% v 43% for HIF-1α-negative patients (P = .0187), whereas 5-year OS was 75% and 54%, respectively (P = .025). In multivariate analysis with International Prognostic Index criteria, HIF-1α remained a significant predictor for PFS (P = .026) and OS (P = .043). Compared with other biomarkers, HIF-1α correlated only with BCL6 (P = .004). In terms of gene expression, we found several common gene associations of HIF-1α and the stromal-1 signature with genes predominantly involved in regulation of the extracellular matrix (eg, BGN, COL1A2, COL5A1, and PLOD2). Conclusion: The expression of HIF-1α protein is an important independent favorable prognostic factor for survival in patients with DLBCL treated with R-CHOP.