STAT5 isoforms regulate colorectal cancer cell apoptosis via reduction of mitochondrial membrane potential and generation of reactive oxygen species

Although the two isoforms of signal transducer and activator of transcription 5 (STAT5) protein, STAT5a and STAT5b, have 94% sequence identity, they are encoded by different genes. Previous studies have been unable to define clearly the roles of the STAT5 genes in colorectal cancer (CRC). To investigate the role of STAT5 isoforms in CRC oncogenesis, immunohistochemical staining was performed. Colorectal adenocarcinomas showed higher expression of STAT5a/5b than normal colonic mucosa (P?