Eng, Charis

Funchain, Pauline

Hesson, Luke B

Packham, Deborah

Pontzer, Emily

Ward, Robyn L

Biological Procedures Online

English

PubMed

Luke B Hesson

Deborah Packham

Emily Pontzer

Pauline Funchain

Charis Eng

Robyn L Ward

Springer - Publisher Connector

A reinvestigation of somatic hypermethylation at the PTEN CpG island in cancer cell lines

Abstract
          
            Background
            
              PTEN is an important tumour suppressor gene that is mutated in Cowden syndrome as well as various sporadic cancers. CpG island hypermethylation is another route to tumour suppressor gene inactivation, however, the literature regarding PTEN hypermethylation in cancer is controversial. Furthermore, investigation of the methylation status of the PTEN CpG island is challenging due to sequence homology with the PTEN pseudogene, PTENP1. PTEN shares a CpG island promoter with another gene known as KLLN. Here we present a thorough reinvestigation of the methylation status of the PTEN CpG island in DNA from colorectal, breast, ovarian, glioma, lung and haematological cancer cell lines.
          
          
            Results
            Using a range of bisulphite-based PCR assays we investigated 6 regions across the PTEN CpG island. We found that regions 1-4 were not methylated in cancer cell lines (0/36). By allelic bisulphite sequencing and pyrosequencing methylation was detected in regions 5 and 6 in colorectal, breast and haematological cancer cell lines. However, methylation detected in this region was associated with the PTENP1 promoter and not the PTEN CpG island.
          
          
            Conclusions
            We show that methylation of the PTEN CpG island is a rare event in cancer cell lines and that apparent methylation most likely originates from homologous regions of the PTENP1 pseudogene promoter. Future studies should utilize assays that reliably discriminate between PTEN and PTENP1 to avoid data misinterpretation.
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Crossref

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A reinvestigation of somatic hypermethylation at the PTEN CpG island in cancer cell lines

Abstract

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