Immunohistochemical expression and clinical significance of P-glycoprotein in previously untreated extranodal NK/T-cell lymphoma, nasal type

✍ Scribed by Biyun Wang; Xiao-Qiu Li; Xuejun Ma; Xiaonan Hong; Hongfen Lu; Ye Guo

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 209 KB
• Volume: 83
• Category: Article
• ISSN: 0361-8609
• DOI: 10.1002/ajh.21256

✦ Synopsis

Abstract

Overexpression of P‐glycoprotein (P‐gp) has been identified by a variety of methods in NK cells and NK malignancies. The aim of this study was to determine the clinical significance of P‐gp in previously untreated extranodal NK/T‐cell lymphoma, nasal type. Tumor specimens from 30 patients initially treated with CHOP or CHOP‐based chemotherapy were examined by immunohistochemistry using JSB‐1, a monoclonal antibody recognizing the intracellular epitope of P‐gp molecule. Twenty cases (67%) were positive for P‐gp expression. The complete response rate achieved in P‐gp positive patients was significantly lower than in P‐gp negative ones (20% vs. 60%, P = 0.045). With a median follow‐up of 25 months, the 2‐year progression‐free survival (PFS) and overall survival (OS) rates for all patients were 66 and 69%, respectively. Compared with both PFS and OS rates of P‐gp positive patients, those of P‐gp negative patients showed a trend of benefit that did not reach statistical significance for borderline P values (PFS: 90% vs. 54%, P = 0.1057; OS: 90% vs. 61%, P = 0.2028). Our results suggest that P‐gp expression is related with poor treatment outcomes of extranodal NK/T‐cell lymphoma, nasal type. Am. J. Hematol., 2008. © 2008 Wiley‐Liss, Inc.