The present study examined 66 cases of gastrointestinal stromal tumors (GISTs), 20 cases of smooth muscle tumors, 20 cases of schwannomas and 20 cases of normal gastric tissues in order to analyze the expression of L1, cluster of differentiation (CD)24 and integrin β1 by immunohistochemical staining. Patients were subjected to follow-up, and survival data were evaluated. L1 expression was detected in 57.6% of GIST cases; this was a significantly higher percentage compared with that found in the smooth muscle tumor cases or the normal control group. CD24 and integrin β1 were also expressed at significantly higher levels in the GIST cases than in the normal control group, although no significant difference was found in the expression levels of these proteins in smooth muscle tumor or schwannoma cases. These higher levels of L1 and integrin β1 expression were associated with an increased risk of invasive GIST, and were significantly positively correlated with Ki-67 expression. CD24 expression was not associated with the risk of GIST invasion or Ki-67 expression. There were positive correlations between L1, CD24 and integrin β1 expression; however, these had no significant association with patient survival. Therefore, L1 alone or in conjunction with CD24 (L1 + CD24), or integrin β1 (L1 + integrin β1) can be considered a valuable indicator for the differential diagnosis of GIST. Furthermore, L1 and integrin β1 can be used alone or in combination to evaluate the biological behavior of GISTs. Future studies are required to evaluate the prognostic value of these markers.
Keywords: L1; cluster of differentiation 24; gastrointestinal stromal tumor; integrin β1.