STAT1 expression is not required for polyp formation in Min mice

Recent studies have suggested the importance of interleukin (IL)-6 signaling in the development of colon cancer. Expression of IL-6 and the IL-6 receptor have been found to be elevated in colorectal carcinoma tissue, and IL-6 has been found to be critical for tumor formation in mouse models of colon cancer. IL-6 mediated activation of the transcription factor STAT1 has been shown to be important in protection of colorectal carcinoma cells from apoptotic signals. To test the hypothesis that the IL-6-STAT1 axis plays a role in early stages of colon cancer development, we examined the role of this pathway in the mouse multiple intestinal neoplasia (Min) model of intestinal tumorigenesis. Due to low fecundity, we were unable to generate Min mice lacking expression of IL-6. We then focused on the role of STAT1 in intestinal polyp formation in these animals. Min mice lacking STAT1 or heterozygous for STAT1 developed polyps in similar numbers as those expressing STAT1. Furthermore, the anatomic distribution and histological characteristics of these polyps did not vary among these populations. These results indicate that STAT1 does not play a role in the pathogenesis of the Min model for colon cancer. However, they do not rule out the possibility that STAT1 plays a role in other stages of colon cancer development.