NO TUMOR-SPECIFIC EXPRESSION LEVELS OF PROTEIN-KINASE-C ISOENZYMES AND OF C-FOS IN HUMAN BREAST-CANCER CELL-CULTURES

Epithelial cells derived from 46 human breast tissue samples of patien ts suffering from breast cancer have been cultivated. Twenty-five of t hese cell cultures stemmed from normal and 21 from tumor tissues. Mode rate to large variations of protein levels of three protein kinase C ( PKC) isoenzymes (alpha, delta and epsilon) were found among the variou s cell cultures. The cell cultures also exhibited very heterogeneous b asal as well as inducible levels of c-fos mRNA. However, none of these variations could be correlated with the character of the original tis sue nor with any clinical parameter of the respective patient. Our res ults suggest that altered levels of PKC isoenzymes or of the protoonco gene c-fos per se cannot serve as an indication for a transformed beha vior of the epithelial cell fraction of human breast tissue.