Regarding the activation of signaling pathways that modulate such effects, it has been reported that Jak2 is essential for the proliferative effects of PRL on the induction of breast tumorigenesis, however, deletion of Jak2 after neoplastic transformation, does not have an impact on survival and proliferation of breast cancer cells in culture or in vivo [6]. The gene discussed is JAK2; the disease is breast carcinoma.