TNF and breast cancer: For instance, KYNA does not affect the secretion of IL-6 or tumor necrosis factor (TNF) by BV-2 mouse microglial cells [88] but reduces the expression of IL-6 mRNA in rat RBL-2H3 mast cells with a subsequent return to baseline [89] and induces IL-6 expression in breast cancer MCF-7 cells [81] and the secretion of TNF, IL-6, IL-1β, and IL-10 by primary mouse splenocytes [90].