LOI of IGF2 is associated with esophageal cancer and linked to methylation status of IGF2 DMR.
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.
Xu
W
W
Department of Pathology and Pathophysiology, Southeast University Medical School, Nanjing, China.
Fan
H
H
He
X
X
Zhang
J
J
Xie
W
W
D019175:DNA Methylation; D004938:Esophageal Neoplasms / Q000235:genetics*; D018392:Genomic Imprinting; D005838:Genotype; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D008745:Methylation; D012150:Polymorphism, Restriction Fragment Length; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D012334:RNA, Neoplasm; D007335:Insulin-Like Growth Factor II