JAK2 and cancer: Icaritin treatment associated anti-cancer and immune-modulation activities through IL-6/Jak2/Stat3 pathways have been demonstrated in cancer cells [11, 12] (Additional file 1: Figure S1) as well as in immune cells including cytolytic natural killer (NK) /T cells, interferon- gamma (IFN-γ)-producing CD8+ T-cells and immune-suppressive myeloid-derived suppressor cells (MDSCs) [13].