[The present and the future of tumor markers]

Recently, it has been revealed that cancer cells produce many substances that are hardly detectable in healthy people. Some of these substances are found in the bloodstream and are clinically used as serum tumor markers. Breakdown products of these serum tumor markers are discharged into the urine; and, therefore, urine can also be a good source of samples for cancer diagnosis. In addition, as other substances remain on or in the cancer cells, we may be able to develop new assay systems using cancer cells as the sample. 1. Serum tumor markers: Many of the recently developed tumor markers are sugar antigens, and are clinically useful for the diagnosis of ovarian cancers. These sugar antigens can be classified into three major categories; core protein-related antigens (CP-RA), core of sugar chain-related antigens (CSC-RA) and periphery of sugar chain-related antigens (PSC-RA). CA125, CA602, and CA130 belong to CP-RA; CA602, CA72-4, and sialyl Tn to CSC-RA; and CA19-9 and sialyl Lewis X (SLX), to PSC-RA. The positive rates of CP-RA in the sera of patients with ovarian epithelial cancers are usually very high except in the case of mucinous cystadenocarcinomas. Meanwhile, those of CSC-RA are higher than those of CP-RA in the sera of mucinous cystadenocarcinoma patients, and the false-positive rate of CSC-RA is lower than that of CP-RA in benign ovarian tumors. The diagnostic efficiency of PSC-RA is inferior to that of CA-RA and CSC-RA. Multi-variate analysis has revealed that the combination assay of these two groups of markers is the most effective among the sugar antigen assays for the diagnosis of epithelial ovarian cancers. 2. Urine tumor markers: beta-core fragment (beta-CF), a fragment of the hCG beta-subunit missing its carboxy-terminal peptide, is often detected in the urine of gynecological malignancies, indicating that urine can be a good sample source for cancer detection.(ABSTRACT TRUNCATED AT 250 WORDS)