Talati et al.’s study revealed that Janus kinase 2 (JAK2) and the signal transducers and activators of transcription 5 (STAT5) A/B (JAK2-STAT5A/B) signaling pathway is involved in promoting the EMT phenotype and expression of the cancer stem cell maker BMI1 in prostate cancer cells. This evidence concerns the gene STAT5A and cancer.