LINE-1 hypomethylation is neither present in rectal aberrant crypt foci nor associated with field defect in sporadic colorectal neoplasia

作者：Quintanilla Isabel; Lopez Ceron Maria; Jimeno Mireya; Cuatrecasas Miriam; Munoz Jennifer; Moreira Leticia; Carballal Sabela; Liz Leoz Maria; Camps Jordi; Castells Antoni; Pellise Maria^*; Balaguer Francesc

来源：Clinical Epigenetics, 2014, 6(1): 24.

DOI：10.1186/1868-7083-6-24

• Colorectal cancer
• Aberrant crypt foci
• LINE-1
• Methylation
• Prevention

Background: Aberrant crypt foci (ACF) are considered the first identifiable preneoplastic lesion in colorectal cancer (CRC), and have been proposed as a potential biomarker for CRC risk. Global DNA hypomethylation is an early event in colorectal carcinogenesis, and long interspersed nuclear element-1 (LINE-1) methylation status is a well-known surrogate marker for genome-wide DNA methylation levels. Despite the gradual increase in DNA hypomethylation in the adenoma-carcinoma sequence, LINE-1 methylation in ACF has never been studied. Moreover, recent studies have reported a field defect for LINE-1 hypomethylation, suggesting that LINE-1 methylation status in normal mucosa could be used to stratify CRC risk and tailor preventive strategies. Thus, we assessed LINE-1 status by pyrosequencing in rectal ACF and paired normal colorectal mucosa from individuals with sporadic colon cancer (CC) (n = 35) or adenoma (n = 42), and from healthy controls (n = 70). %26lt;br%26gt;Findings: Compared with normal mucosa, LINE-1 in ACF were hypermethylated across all groups (P %26lt; 0.0001). Furthermore, LINE-1 methylation status in normal colorectal mucosa was independent of the presence of adenoma or CC (P = 0.1072), and did not differ depending on the distance to the adenoma or CC. Interestingly, when we compared the LINE-1 methylation status in normal mucosa from different segments of the colorectum, we found higher hypomethylation in the rectum compared with the descending colon (P %26lt; 0.0001). %26lt;br%26gt;Conclusions: Overall, our results suggest that global hypomethylation is not present in rectal ACF and argues against the existence of LINE-1 methylation field defect in sporadic colon cancer.

• 出版日期2014-11-10