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Citation to Chalichagorn et al. [26]

Posted by Apiwat on 14 May 2007 at 13:04 GMT

Dear Editor,

The article demonstrated interesting observation that LINE-1 methylation level can be varied among normal tissues and cancers. However, the article incorrectly cited the work of our group (Chalitchagorn et al. 2004) that “Chalichagorn et al. [26] did not showed a marked difference in methylation between normal samples from various tissues.”. On the contrary, our paper emphasized the same finding. We reported that the LINE-1 methylation levels in normal tissues are distinct. We stated in our title and abstract that normal tissues from different organs showed tissue-specific levels of methylated LINE-1. We also compared in result LINE-1 methylation in different normal tissues and found that the levels of hypomethylation in thyroid (42.61–73.71%) and esophageal tissue (34.42–68.49%) were widely distributed. Strikingly, the levels of LINE-1 methylation demonstrated by COBRA were significantly different among different tissue types, for
example, normal colonic epithelium and connective tissue (P<0.05) or urothelium (64.36–65.90%) and renal epithelium (58.02–60.41%) (P<0.00001). Variation of LINE-1 methylation level among cancer cases were also demonstrated in our study. Our data suggest that this epigenetic event may be continuously altered in adult tissues by the processes of cellular differentiation and cancer development.

Sincerely,
Apiwat Mutirangura
Chulalongkorn University

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