 Continuous activation of the JAK-STAT pathway can cause cancer in humans as well as less complex organisms such as Drosophila.Given the preliminary evidence and their effects on important signaling pathways involved in cancer, PIAS proteins may be interesting targets for the development of treatments for cancers or as sensitizers for chemotherapeutic drugs and radiation in BRCA-deficient cancers.In addition to its importance in various cancers, the JAK-STAT signaling pathway plays an important part in the human immune response and in particular with regards to adaptive immunity.