STAT3 and cholangiocarcinoma: To elucidate whether the paracrine interactions with stromal cells led to an altered signal transduction in CCA cells, Western blot analyses of CCA cells exposed to medium or conditioned medium from either stromal cell line in the absence or presence of 1 μM Sorafenib were conducted to detect activated (phosphorylated) forms of STAT3, JNK, ERK and AKT (Figure 5A).