Aneuploidy characterizes adjacent non-malignant mucosa of ulcerative colitis-associated but not sporadic colorectal carcinomas: a matched-pair analysis.

INTRODUCTION: Aneuploidy has been suggested as independent prognostic marker in ulcerative colitis (UC) patients for developing UC-associated colorectal carcinomas (UCCs). UCCs are associated with a poorer prognosis and more frequently present with synchronous carcinomas when compared with sporadic colorectal carcinomas (SCCs). The authors therefore investigated if the adjacent non-malignant mucosa of aneuploid UCCs and aneuploid SCCs shows differences regarding the frequency of aneuploidy and if this aneuploidy is associated with histomorphological alterations.
METHODS: Primary tumors of 25 UCCs and 20 SCCs were selected showing exclusively aneuploid DNA patterns and matching DNA stemlines. The UCCs' (n = 82) and SCCs' (n = 40) adjacent non-malignant mucosa were evaluated for histopathology and assessed for DNA ploidy status by image cytometry.
RESULTS: UCCs' non-malignant mucosa showed dysplasia in 31.7% and aneuploidy in 89%. In contrast, SCCs' non-malignant mucosa revealed no dysplasia and aneuploidy in only 5%. Irrespective of dysplastic lesions, aneuploidy was observed more frequently in adjacent non-malignant mucosa of UCCs than of SCCs (p < 0.001). Neither a correlation between aneuploidy and inflammation (p = 0.916) nor between aneuploidy and dysplastic lesions (p = 0.159) could be observed.
CONCLUSION: Aneuploidy is more frequent in adjacent non-malignant mucosa of aneuploid UCCs than in adjacent non-malignant mucosa of aneuploid SCCs. Furthermore, aneuploidy seems to be irrespective of inflammation or dysplasia. The results therefore emphasize the importance of aneuploidy for UC-associated carcinogenesis and its potential as new diagnostic target.