STAT3 and glioblastoma: It has been reported that ~89% of human glioblastoma samples demonstrate low expression of PIAS3 and elevated STAT3 expression, and the ectopic addition of PIAS3 to glioblastoma cells results in inhibition of pSTAT3 activity.480 rPP-C8, a derivate of PIAS3, is a polypeptide derived from the C-terminal acidic region of PIAS3.