Interferon-inducible gene family 1-8U expression in colitis-associated colon cancer and severely inflamed mucosa in ulcerative colitis

Persistent severe inflammation in colonic mucosa is thought to cause the development of colon cancer in patients with ulcerative colitis (UC). However, predisposing genetic abnormalities have not been identified in this sequence. Using differential display PCR, we isolated cDNA fragments corresponding to mRNAs that were differentially expressed in colitis- associated cancer tissues and mucosa with mild inflammation in the colon of five UC patients. This molecular screening approach identified 60 cDNA fragments, and we sequenced 34 fragments. One cDNA fragment, which is identical to IFN-inducible gene family 1-8U, was strongly expressed in all five UC-associated cancers. 1-8U was also expressed in sporadic colon cancer tissues and colon cancer cell lines, but not in normal mucosa. This gene was strongly expressed in severely inflamed colonic mucosa of UC without colitis- associated colon cancer, although 1-8U expression was not related to the extent and duration of the disease. However, 1-8U was expressed in the colonic mucosa of all patients with chronic, continuously severe inflammation. These results indicated that IFN-inducible gene family 1-8U expression in inflamed colonic mucosa might be used as a preferential marker of colitis-associated colon cancer in UC.