Phosphorylation of STAT 3 correlates with HER 2 status, but not with survival in pancreatic ductal adenocarcinoma

Activation of signal‐transcriptional factor signal transducer and activator of transcription 3 ( STAT 3) is associated with more aggressive behaviour in a variety of human malignancies. As selective STAT 3 inhibitors exist, this protein might represent a novel therapeutic target. Although STAT 3 seems to play an important role in progression of pancreatic ductal carcinoma ( PDAC ), only few data on this subject exist. The aim of our study was the investigation of STAT 3 activation and its correlation with its possible regulator HER 2. Expression of tyrosine‐705 phosphorylated STAT 3 ( pSTAT 3) was determined immunohistochemically in 79 PDAC s. HER 2 status assessed by immunohistochemistry and double colour silver in situ hybridization was available from a previous study. PSTAT 3 expression was seen in 33 (41.8%) patients. Six patients were scored as HER 2 positive having strong correlation with pSTAT 3 expression (p = 0.004, Fisher′s exact test). No association of pSTAT 3 expression with patients′ age, tumour staging and grading, perineural invasion of tumour cells or survival time was seen. pSTAT 3 is frequently expressed in PDAC . Nevertheless, its immediate clinical relevance seems to be low. However, further research needs to determine whether STAT 3 status in PDAC is predictive for the response to novel targeting therapies.