CXCL8 and breast cancer: In line with these data, PGZ inhibited the expression of IL6 (−19%, p<0.05), Interleukin 8 (IL8, −31%, p<0.05), SLUG (−18%, p<0.05) and TNFα (−54%, p<0.01) in the breast cancer estrogen receptor-α (ERα) negative cell line MDA-MB-231 (Figure S6).