Desmoid tumor-associated pain is dependent on mast cell expression of cyclooxygenase-2

This study aimed to investigate the expression profile of cyclooxygenase-2 (COX-2) in desmoid tumor specimens and to evaluate the correlation of intratumoral COX-2 expression with pain status. Sixteen patients with histologically proven desmoid tumors who attended our institution between 2003 and 2010 were enrolled in this study. COX-2 protein expression in desmoid tumors was determined by immunohistochemistry. COX-2 - positive cells had similar morphology to that of mast cells, and therefore, immunohistochemical staining for tryptase was performed in co-localized sections. The number of COX-2 -positive cells in 10 consecutive fields was counted at 400× magnification. Patients were stratified into 2 groups according to the number of COX-2- positive cells, the COX-2 -positive group (≧10 COX-2 -positive cells) and the COX-2 -negative group (