Disialosyl globopentaosylceramide (DSGb5) is a ganglioside originally isolated from tissue extracts of renal cell carcinoma (RCC) with metastasis. Previous in vitro experiments have suggested that DSGb5 promotes metastasis by enhancing the migration of RCC cells and downregulating NK cell cytotoxicity against RCC cells. In this study, we investigated the clinicopathological significance of DSGb5 expression in RCC and outcomes of RCC patients. A total of 156 RCC patients who underwent surgical treatments at our hospital from January 2007 through December 2012 were analyzed in this study. The expression of DSGb5 in RCC specimens was examined by immunohistochemical staining with monoclonal antibody 5F3. The immunostaining intensity of RCC tissues was assessed in comparison with that in benign renal tubules as an internal positive control. The relationship between DSGb5 expression and clinicopathological characteristics was investigated and recurrence free survival following surgery was evaluated. Microvascular invasion was observed in 68% (n = 19/28) and in 45% (n = 58/128) of the DSGb5 high expression group and low expression group, respectively (p = 0.031). Of 156 patients with a median follow up of 51 months, 18 patients (12%) developed metastasis following surgery. Patients in the DSGb5 high expression group showed significantly lower recurrence-free survival as compared with those in the DSGb5 low expression group (log-rank P = 0.047). In the present study, DSGb5 expression was associated with microvascular invasion in RCC tissues, and patients with DSGb5 high expression showed significantly lower recurrence-free survival rates. These findings suggest that DSGb5 expressed in RCC is correlated with metastasis and is a potential predictor for identifying patients who experience metastasis after surgery.
Keywords: DSGb5; Ganglioside; Metastasis; Renal cell carcinoma; Vascular invasion.