Usefulness of serological determinations of soluble 53 kDa protein in follow-up of melanoma patients.

The role of the soluble 53 kDa antigen (s53) determinations in follow-up of melanoma patient was studied. High performance liquid chromatography (HPLC ) was used to measure serum levels of s53 antigen after its partial isolati on on gel fiberglass (GFG) affinity chromatography columns. Two main protei ns were isolated from these columns as representatives of soluble tumor-ass ociated antigens (TAA) with molecular masses of 64 and 53 kDa. In a Western immunoblot analysis, the 53 kDa protein exhibited a strong positive reacti on to the commercial p53 antibody. HPLC isolated both antigens with individ ual variations and significant differences in their concentrations in patie nts from different groups. The presence of metastases was manifested by a s ignificant increase in the serum levels of both isolated TAA. This finding is in accordance with our previous observations on the role of the soluble 53 kDa protein in the development of colon and uterine cancers. We conclude that the determination of the serum level of the s53 antigen is of diagnos tic significance in the monitoring of melanoma patients.