These inhibitors work by targeting different JAK family members, as shown in Fig. 3, thus interfering with THE STAT3 pathway which is a crucial signalling pathway that promote cancer cell survival and proliferation through gene expression. For instance, Ruxolitinib, an inhibitor of JAK1 and JAK2, competitively inhibits the ATP-binding catalytic site on these kinases [47]. The gene discussed is JAK2; the disease is cancer.