The expression patterns of glycolipids of human renal-cell carcinoma were studied in primary tumors from 23 cases and 5 metastatic lesions from 4 cases using HPTLC (high-performance thin-layer chromatography). The expression pattern of glycolipids in primary tumors was characteristic of the histological cell type. In granular-cell carcinoma, lactosylceramide (CDH), GM3 and the longer-chain gangliosides (gangliosides migrating more slowly than GM3) increased, although in clear-cell carcinoma, CDH and other glycolipids tended to decrease. Globoside decreased in all cases but one, irrespective of cell type. In metastatic lesions of the clear-cell type, the prominent increase in longer-chain gangliosides was characteristic. Furthermore, the same expression pattern as that of metastastatic lesions was shown in 3 of 14 patients with primary clear-cell carcinoma, all of whom developed metastases soon after radical nephrectomy. These studies indicate that the increased expression of the longer-chain gangliosides in primary tumor is one of the factors associated with high metastatic potential, and also predict early post-operative development of metastasis.