Studies of multiple markers in
tumors are required for adequate
biological characterization. We have characterized the expression of multiple
proteins in human ovarian
tumors using the technique of 2-dimensional gel electrophoresis (2-DE/PDQUEST).
Tumor cells were prepared from the tissue of 22 ovarian
tumors. Large variations were observed between
tumors in the expression of various
polypeptides, indicating heterogeneity in gene expression. An increase in the spot density of 2 cell-cycle-related
proteins,
PCNA and OP18/
stathmin, was observed in
carcinomas. Borderline
tumors expressed low levels of these
proteins. Significant increases in the levels of nm23, GST-pi,
elongation factor 2 and
triose phosphate isomerase were recorded in ovarian
carcinomas. Furthermore, decreases in the levels of tropomyosin-2 and
lamin C were observed in malignant as compared with benign
tumors. The pattern of expression of 9
protein markers was examined in individual
tumors. All malignant
tumors showed simultaneous alterations in the expression of 5 or more of these
proteins, whereas no benign
tumor showed alterations in the expression of more than 3
polypeptides. Borderline
tumors showed alterations in 0 to 6 markers. We conclude that the simultaneous analysis of multiple
polypeptides, which can be achieved by 2-DE, is useful for characterization of gene expression and diagnostic studies in ovarian
tumors.