Moreover, the protein expression levels of pSTAT3 measured by IHC, may not reflect the exact transcriptional activity of STAT3, as STAT3 has two splice variants: α and β.10 STAT3β is suggested to function as a tumor suppressor and a negative regulator of STAT3α which has mainly tumor promoting activities.32 In the current study we cannot differentiate STAT3α from STAT3β with the antibodies used. Here, STAT3 is linked to neoplasm.