Expression and clinical significance of H-caldesmon in gastrointestinal stromal tumor: is it a specific marker for myogenic differentiation?

Objects: To investigate the expression and clinical significance of H-caldesmon which is considered a myogenic marker in GIST. Methods: The clinical information of 105 patients diagnosed with GIST was obtained from Yantai Yuhuangding Hospital and Rambam Health Care Campus. Morphology, the results of immunohistochemical staining and available molecular detection were reviewed. The expression of H-caldesmon was detected for each specimen by immunohistochemical staining. Comparative analysis was carried out between H-caldesmon expression and clinicopathologic parameters. Results: H-caldesmon was expressed in all patients with GIST including tumors outside the gastrointestinal tract and with CD117-negative expression. Although the pattern of expression was different, the positive rate in our study group was 100%. There was no statistically difference between H-caldesmon expression and parameters such as gender, age, location, morphology, risk, immunologic markers, and molecular mutation. Conclusions: H-caldesmon is expressed positively in GIST and might not be a specific marker for smooth muscle and associated tumors. GIST outside the gastrointestinal tract or with CD117-negative expression should not be misdiagnosed assmooth muscle tumor because of the positive expression of H-caldesmon in the differential diagnosis. Comprehensive analysis combined with other immunological markers and molecular detection is needed.