HORMONE-REGULATED GENES (PS2, PIP, FAS) IN BREAST-CANCER AND NONTUMORAL MAMMARY TISSUE

Expression of the hormone-regulated genes, pS2, prolactin-inducible pr otein (PIP) and fatty acid synthetase (FAS), was investigated by North ern blotting in primary breast carcinoma, metastatic breast cancer in axillary lymph nodes, in uninvolved breast tissue from mastectomies an d in normal lymph nodes. There were considerable differences in expres sion of the genes between the tissues. The proportion of tissues conta ining PIP-mRNA decreased from uninvolved breast tissue to primary brea st carcinoma to metastatic carcinoma. The reverse applied to FAS-mRNA which was found more often in metastatic cancer than in primary cancer , and least frequently in uninvolved breast tissue. Yet another patter n was observed for pS2 expression. The highest proportion of tissues d emonstrating gene expression was found in primary breast cancer with b oth metastatic tumor and uninvolved breast tissue expressing the gene less frequently. pS2-mRNA and PIP-mRNA could only rarely be detected i n trace amounts in normal lymph nodes. In contrast, FAS-mRNA was prese nt in about one third of normal lymph nodes. Only pS2-mRNA showed an a ssociation with estrogen and progesterone receptor status.