STAT3 and neoplasm: Western blot analysis indicated that caspase-3/EndoG knockout significantly reduced the level of phosphorylated STAT3 at Y705 (pSTAT3) in mPOR-transformed cells (Fig. 5F) as well as in tumor samples from Casp3WT;Pymt and Casp3KO;Pymt mice (Fig. 5G).