Involvement of focal adhesion kinase in the progression and prognosis of gastrointestinal stromal tumors.
BACKGROUND Evidence suggests that focal adhesion kinase (FAK) is involved in the pathogenesis of certain cancers. Focal adhesion kinase is overexpressed in invasive and metastatic cancers of the breast, colon, thyroid, and prostate. The objective of this study was to determine the presence and cellular distribution of FAK in oral cancer and determine whether there is a difference in FAK expression in preinvasive and invasive oral cancers. METHODS Immunohistochemistry was used to detect FAK expression in 20 archival oral cancer specimens. RESULTS Focal adhesion kinase immunoreactivity was detected in all specimens that were examined. In tumors, there was an increase in the intensity of FAK staining and in the percentage of FAK-positive cells. Preinvasive tumors had populations of cancer cells which stained more intensely than neighboring cancer cells. CONCLUSIONS Focal adhesion kinase expression appears to be increased in invasive and preinvasive oral cancers. It is speculated that enhanced expression of FAK may contribute to the aggressive phenotype of oral cancers.