Expression of alpha6 integrin subunit is associated with malignancy in gastric gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common non-epithelial neoplasms of the gastrointestinal tract. The aim of this study was to investigate the clinicopathological and immunohistochemical features of gastric GISTs and to evaluate the degree of integrin expression in order to determine the need for surgery or predict the prognosis for GIST patients.

Clinicopathological findings were obtained from patients' records. Specimens from 32 cases of gastric GIST were analyzed with immunohistochemical methods. The c-kit negative examples among the original 48 patients with gastric submucosal and muscle layer tumors were excluded from the study.

There was a significant correlation between p53 protein expression and tumor malignancy. The positive staining for proliferating cell nuclear antigen was observed in all patients, and the mean tumor proliferation index for benign and malignant groups were 3.0% and 16.3%, respectively. alpha5beta1 integrin and alpha6 integrin subunit were expressed from moderately to strongly in tumor cells, and alpha 6 integrin subunit expression correlated significantly with whether tumors were classified as benign or malignant. However, there were no significant differences between the survival of GIST patients and integrin expression, mitotic rate, tumor size, or tumor malignancy.

Malignant GISTs show significant expression of alpha6 integrin subunit. It may be useful in supporting other parameters, such as p53, MI, and tumor size. We suggest that alpha6 integrin subunit expression may be useful as an indication for surgery and also as one of several prognostic factors.