STAT3 and cancer: It has been found that COL17A1 is expressed in malignant but not in benign melanocytic tumors [13], recent reports also showed the expression of COL17A1 in colon epithelium and the association of increased COL17A1 expression with poor outcome in colorectal carcinoma [14]; suspension survival mediated by PP2A-STAT3-COLXVII determines tumor initiation and metastasis in cancer stem cells [24], demonstrating its important role in tumor pathogenesis.