IL6 and neoplasm: Although our study is not the first to report the source of Shh and IL-6, individually, in agreement with others our findings indicate that epithelial cells express a higher level of Shh and IL-6 than stromal fibroblasts, suggesting that Shh and IL-6 produced by both epithelial cells and stromal cells are released into blood serum that can lead to enhanced metastatic progression of tumor cells.