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


METHODS
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 (<10 COX-2 -positive cells). The prevalence of painful tumors was compared between the 2 groups.


RESULTS
COX-2 was expressed in 9 patients (56%). COX-2 proteins were expressed not in tumor cells but in tryptase-positive mast cells in the stroma of desmoid tumors. 6 of 9 patients in COX-2 -positive group had painful tumors. This difference was statistically significant according to the chi-squared test (p = 0 .036), suggesting a positive correlation between COX-2 expression and tumor-associated pain.


CONCLUSIONS
Our results indicated that COX-2 secretion from mast cells modulates desmoid tumor-associated pain. In addition, mast cells may at least in part contribute to the pathogenesis of desmoid tumors.
The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1490389349103056.
Department of Orthopedic Surgery, Sapporo Medical University School of Medicine, West 16, South 1, Chuo- ku, Sapporo 060-8543, Japan. emrmkt@yahoo.co.jp.
Makoto
M
Emori
Mitsunori
M
Kaya
Tomoko
T
Mitsuhashi
Hiroko
H
Asanuma
Toshihiko
T
Yamashita
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D005260:Female; D018222:Desmoid Tumors / Q000150:complications / Q000201:enzymology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008407:Mast Cells / Q000201:enzymology* / Q000473:pathology; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000378:metabolism*
D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human