Cyclooxygenase-2 expression in gastrointestinal stromal tumours

Gastrointestinal stromal tumours (GIST) are the most frequently encountered mesenchymal tumours of the gastrointestinal tract. GIST represents the subgroup of CD-117 (c-kit) positive sarcomas that is originating from the gastrointestinal tract extending to the abdominal cavity. It is known that cyclooxygenase-2 (COX-2) expression is increased in colorectal adenoma and carcinoma, however there is a limited number of studies in stromal tumours regarding the expression of COX-2. A total of 42 reconfirmed GIST cases (26 males and 16 females) is included in this study. An immunohistochemical COX-2 staining was performed to all cases in the Pathology Department of Gaziantep University. The mean age of the study population is 56.85 ± 12.90 years (32-77 years). The primary site of GIST is stomach in 50%, small bowel in 35.8%, large bowel in 7.1% and other in 7.1%. We found a statistically significant correlation between the tumor mitosis and COX-2 expression in GIST. However, there was no relationship between COX-2 expression and death rate, presence of metastasis, tumour size, risk staging, usage of tyrosine kinase inhibitor, and complete resection rate. In the light of these findings, the usage of COX-2 inhibitors with or without tyrosine kinase inhibitors in GIST patients may be helpful in the adjuvant setting to prevent or delay recurrences. Moreover, we need more studies to define the status of COX-2 inhibitors in GIST.