NORMAL BREAST EPITHELIAL-CELLS PRODUCE INTERLEUKIN-6 AND INTERLEUKIN-8 TOGETHER WITH TUMOR-NECROSIS-FACTOR - DEFECTIVE IL6 EXPRESSION IN MAMMARY-CARCINOMA

Virtually pure primary cultures of normal mammary epithelial cells (MEC) obtained from healthy women were shown to release interleukin 6 and 8 (IL6, IL8) and to produce a non-secreted form of tumor-necrosis factor (TNF). No interferon (IFN), whether alpha, beta or gamma, or IL1-alpha or -beta could be detected. Analysis of cellular RNA confirmed these findings and showed that MEC also express IL6 receptor and TNF-alpha-related mRNAs. Epithelial cells were selectively stained by antibodies to IL6, IL8 and TNF-alpha both in primary cultures and in the normal mammary gland. Samples of human milk contained sizable amounts of IL6, IL8 and IFN-gamma; yet the liquid phase was consistently negative for other cytokines (i.e., TNF-alpha, IFN-alpha/-beta, IL1-alpha/-beta). Expression of IL6 (but not of IL8 and TNF-alpha) was abolished in ductal infiltrating carcinomas and greatly reduced in cultures of oncogene-transfected mammary cells, suggesting that alterations of IL6 expression are associated with pathogenesis in breast cancer. (C) 1993 Wiley-Liss, Inc.