Expression of globo-series gangliosides in human renal cell carcinoma

Gangliosides have been shown to be involved in development, differentiation, oncogenesis, and cancer progression. We investigated immunohistochemical expression of globo-series gangliosides in human renal cell carcinoma (RCC) and whether their expression is related to the clinical course. The expression of globo-series gangliosides was evaluated in fresh-frozen sections of 55 primary renal tumors and 8 metastatic deposits using monoclonal antibodies RM1 and RM2, which define monosialosyl and disialosyl galactosylgloboside, respectively. The immunoreactivity of primary tumors to RM1 and/or RM2 was correlated with the clinicopathological data. Cumulative incidence of metastasis detected at initial diagnosis and during the follow-up period was significantly higher in the cases whose primary tumors were RM1/RM2-positive (RM1 and/or RM2-positive) than in the RM1/ RM2-negative (neither RM1 nor RM2-positive) cases (P < 0.05). During the follow-up period, metastasis developed in none of the RM1/RM2-negative cases which had not shown metastasis at initial diagnosis. High nuclear grade was observed only in the RM1/RM2-positive cases. The RM1/RM2-positive rate of the metastatic deposits was higher than that of the primary tumors. Furthermore, a metastatic deposit obtained from one of the cases whose primary tumors were equivocal for RM1/ RM2 was extensively stained by RM1 and RM2. These results indicate that globo-series gangliosides may be one of the biochemical indicators related to the metastatic potential of human RCC.