Objective: To investigate methylation status of Wif-1 and β-catenin expression in colorectal serrated lesions.
Methods: Various colorectal lesions were collected including 52 cases of hyperplastic polyps, 41 cases of sessile serrated adenoma, 23 cases of traditional serrated adenoma, 24 cases of colorectal cancer and 24 cases of normal mucosa. All specimens were subject to immunohistochemical staining of β-catenin.SYBR Green PCR analysis of Wif-1 promoter methylation was performed in 29 cases of hyperplastic polyps, 29 cases of sessile serrated adenoma, 19 cases of traditional serrated adenoma, 14 cases of colorectal cancer and 16 cases of normal mucosa.
Results: Abnormal expression rates of β-catenin in normal mucosa, hyperplastic polyps, sessile serrated adenoma, traditional serrated adenoma and colorectal cancer were 12.5% (3/24), 59.6% (31/52), 63.4% (26/41), 73.9% (17/23) and 100.0% (24/24), respectively. The corresponding methylation rates of Wif-1 promoter were 2/16, 10/29 (34.5%), 16/29 (55.2%), 15/19 and 13/14 (P < 0.05), respectively. Abnormal β-catenin expression was positively correlated with Wif-1 promoter methylation in traditional serrated adenomas (r = 0.536, P < 0.05).
Conclusions: Abnormal β-catenin expression and methylation rate of Wif-1 promoter are significantly higher in colorectal serrated lesions. Methylation of Wif-1 promoter may be related to the abnormal expression of β-catenin through activation of Wnt/β-catenin signaling pathway, which may contribute to the development of colorectal serrated lesions.