LOI of IGF2 is associated with esophageal cancer and linked to methylation status of IGF2 DMR.

摘要

In the present study, IGF2 mRNA expression was examined by semi-quantitative RT-PCR in 46 esophageal cancer cases. LOI of IGF2 was detected in informative samples, which were determined as heterozygote with ApaI polymorphism in exon 9 of IGF2 by PCR-RFLP and RT-PCR-RFLP. Methylation status of IGF2 DMR in informative samples was analyzed by sodium bisulfite treatment and PCR and the following cloning sequencing. The results showed that there was over-expression of IGF2 mRNA in tumor tissues (T) compared to their matched normal tissues (N) (P < 0.05). The expression level of IGF2 in tumor tissues was associated with pathological grades (P < 0.05), but proved irrelevant to clinical stages (P > 0.05). Of all informative samples, 21% (5/24) of cases showed there were IGF2 LOI; however, there was IGF2 LOI in the tumor tissue and not in its matched normal tissue in a special case. Methylation level of IGF2 DMR was average 29.7% in normal imprinting samples and 50.6% (P < 0.01) in IGF2 LOI separate samples. These data suggested that IGF2 may participate in carcinogenesis of esophageal cancer through its over-expression. IGF2 LOI may be one of the factors that lead to overexpression of IGF2 and may be at least partly due to aberrant methylation of IGF2 DMR in esophageal cancer.