In vitro studies have shown that IL-1 activation in 4T1 cells involves the intracellular signals STAT3, JNK, ERK, AKT, and NF-κB, which may be involved in cell proliferation and survival, but phosphorylation occurs only at the JNK, ERK, and AKT levels in Hs578T human breast cancer cells. This evidence concerns the gene MAPK8 and breast cancer.