Gastrointestinal neuroendocrine cell carcinoma (NEC) is a highly aggressive tumor with poor prognosis, for which an effective therapy is highly desirable. Recently, use of a c-kit inhibitor achieved excellent results against gastrointestinal stromal tumor (GIST) that showed c-kit overexpression and mutation in most cases. According to recent studies, 17–44% of pulmonary NEC also expressed c-kit and the antitumor effect of c-kit inhibitor was demonstrated in vitro against small cell carcinoma of the lung. As gastrointestinal NECs are clinicopathologically similar to pulmonary NECs, we investigated c-kit expression and mutation in gastrointestinal NEC.Methods
Surgically resected gastrointestinal NEC was examined for c-kit expression by immunohistochemistry and RT–PCR. Mutation of the c-kit gene was also investigated by means of single-strand conformation polymorphisms (SSCP).Results
Twenty-six percent (6 out of 23 patients) of gastrointestinal NEC expressed c-kit protein. c-kit protein expression was demonstrated in 1 out of 4 colorectal, 1 out of 2 duodenal, 4 out of 16 gastric and no esophageal (sample size of 1) NECs. The results of immunohistochemistry for c-kit were consistent with the RT–PCR. No c-kit gene mutation was found in gastrointestinal NEC.Conclusion
The frequency of c-kit expression in gastrointestinal NEC was similar to that previously reported for pulmonary NEC. These findings suggest that c-kit inhibitor may be effective against some gastrointestinal NECs.