Significance of D2-40 expression in the diagnosis of gastrointestinal stromal tumor.

We incidentally found the expression of D2-40 in Cajal interstitial cells for the immunohistochemical valuation of lymphatic invasion by gastric and colonic cancer cells. Therefore, we suggested that D2-40 might become an available marker for gastrointestinal stromal tumors (GISTs). In this study, we performed immunohistochemical study of 21 GISTs, As a result, we confirmed a positive reaction for D2-40 in sixteen GISTs. Among sixteen tumors, thirteen tumors were focally positive and remaining three tumors were diffusely positive. We could find no relationship between positive findings for D2-40 and size or location of the tumor. Three of four tumors with intermediate risk of aggressive behavior and two of four tumors with recurrence showed a negative reaction for D2-40. In conclusion, we suggest that D2-40 may be an available marker of GISTs, but the expression of D2-40 seems to be not associated with the degree of risk of aggressive behavior.