OBJECTIVETo investigate the clinicopathological characteristics of 180 patients with wild type gastrointestinal stromal tumors(GIST).

METHODSThe clinicopathological data of 180 patients with wild type GIST treated in the Peking University Cancer Hospital between October 2001 and September 2013 were analyzed and compared to 513 mutant patients.

RESULTS180 patients were included in this study, and the median age 52.5 years(16-78 years). The percentage of female was significantly higher than that of male among patients under the age of 40. Primary tumor sites mainly included stomach(45.6%) and small intestine(23.9%). The positive expression of CD117, DOG-1, and CD34 were 81.6%, 75.6%, and 74.7%, respectively, which were highest in stamach, secondly in small intestine. The percentage of tumor with length >5 cm was higher in patients under the age of 50 compared to patients more than 50 years, and a significant correlation was found between tumor size and mitosis. Compared to mutant patients, wild type patients had the following features: younger, primary tumor site of stomach, tumor length ≤ 2 cm, and the lower positive expression of CD117 and DOG-1.

CONCLUSIONSThe significant differences in primary tumor sites, tumor size, and the positive expression of CD117/DOG-1 were found between wild type GIST and mutant GIST, which suggested that wild type GIST might be an independent subgroup to be concerned in clinical practice.