STAT3 and neoplasm: The tumor suppressive role of SHP-1, encoded by PTPN6 gene, has been made clear by reports of its negative regulation of several key oncogenic tyrosine kinases such as the JAK kinases (David et al. 1995; Jiao et al. 1996; Haque et al. 1998; Migone et al. 1998) and STAT3 (Tai et al. 2011).