Based on these concepts, the synergistic treatment effect of ruxolitinib and calcitriol combination in luminal B subtype MCF7-HER18 breast cancer cells in our previous study could be interpreted as follows: the antagonistic effect of ruxolitinib and calcitriol combination treatment related to ERα expression can be compensated by the downregulation of HER2 phosphorylation through JAK2 suppression of ruxolitinib. The gene discussed is JAK2; the disease is breast carcinoma.