High immunohistochemical expression of p‐AKT predicts inferior survival in patients with diffuse large B‐cell lymphoma treated with immunochemotherapy

Abstract

Summary Chemotherapy and rituximab (R) is current standard therapy in diffuse large B‐cell lymphoma (DLBCL), but a substantial proportion of patients still fail to reach sustained remission. In vitro studies have indicated that rituximab resistance could be accompanied by dysregulated apoptotic pathways, such as the phosphatidylinositol 3‐kinase (PI3K)/AKT signaling pathway, which can be constitutively activated in DLBCL. In this retrospective, immunohistochemical study on 106 patients treated with R‐CHO(E)P (cyclophosphamide, doxorubicin, vincristine, prednisone, rituximab [+etoposide]), we investigated the prognostic role of proteins involved in different apoptotic pathways; phosphorylated AKT (p‐AKT), bcl‐2, MCL1, bcl‐xL, Bax and Bak. High p‐AKT expression (>108 cells/mm 2 , highest quartile, n = 27) predicted worse progression‐free (PFS) ( P = 0·02) and overall (OS) ( P = 0·01) survival, independent of International Prognostic Index and sex. Also bcl‐2+ (cut‐off 50%) predicted worse PFS ( P = 0·005) and OS ( P = 0·05) but after adjustment for clinical factors only the influence on PFS ( P = 0·03) remained significant. The prognostic impact of p‐AKT overexpression was independent of bcl‐2 status. MCL1, bcl‐xL, Bax and Bak expression did not add any prognostic information. Our results suggest that high p‐AKT expression predicts worse outcome , possibly indicating that inhibition of the activated PI3K/AKT pathway could be of clinical interest in DLBCL patients. In addition, bcl‐2 status could have prognostic importance also in the era of immunochemotherapy.