The “Cytokine-cytokine receptor interaction” transduction pathway, including IL1B, IL1A, IL1R, IL6, IL6ST, IL7R, IL1RAP, INHBA, OSMR and TGFBR2 that are strongly associated with breast cancer progression [35–41], was found significantly correlated with HIF-1α. Here, IL6 is linked to breast carcinoma.