Hepatocyte growth factor and c-Met immunoreactivity are associated with metastasis in high grade salivary gland carcinoma

Interactions between hepatocyte growth factor (HGF) and its receptor, c-Met, have been associated with invasion, metastasis and carcinogenesis in in vitro experiments. We investigated the relationship between HGF/c-Met immunoreactivity and the clinical features of 33 patients with high grade salivary gland carcinomas. c-Met and stromal HGF (expression of HGF in fibroblasts adjacent to tumor nests) were found to significantly correlate with regional lymph node and distant metastasis (p<0.05), but not with HGF expression, in tumor cells. Stromal HGF was also found to correlate with tumor size (p<0.05). In addition, a significant correlation between c-Met and stromal HGF expression (p<0.0001) was observed. Overall survival in patients with c-Met and stromal HGF immunoreactivity was significantly worse than in patients without c-Met and stromal HGF immunoreactivity (p=0.0002). The present findings suggest that HGF may bind to c-Met in a paracrine fashion, thereby enabling metastasis of high grade salivary gland carcinomas. Thus, HGF/c-Met immunoreactivity might be associated with a poor prognosis in patients with high grade salivary gland carcinomas.