The potential of identification of a malignancy‐associated biomarker in breast cancer diagnosis and research: hTERT gene DNA methylation

Abstract

DNA hypermethylation has been documented to be prominent at a CpG island rich region about 600 bp upstream the transcription start site of the hTERT gene using qualitative methylation specific PCR on DNA isolated from tumor cell lines. In order to assess the potential significance of this biomarker in breast cancer research and diagnosis, we explored if such findings are reproducible on surgically resected fresh breast tumor cells. Using quantitative pyrosequencing technology, we investigated and present methylation status of four CpG islands of this region in a cohort of 77 invasive breast carcinomas using normal breast tissue as controls. Globally, a significant hypermethylation in tumor cells was observed in the four CpG islands as a sum, in comparison to methylation of the normal breast tissue. Individually, certain CpG islands displayed methylation greater than 50% in about 3/4 of the 77 breast cancers, but in none of the normal breast tissue. Our results highlight the value of DNA hypermethylation in the -600 bp region of the hTERT gene as a potential marker for breast cancer diagnosis. We believe that integration of this novel, malignancy-associated molecular testing with morphology is of significant value in the accurate interpretation of small tumor sample size obtained via fine needle aspiration biopsy, ductal lavage, and nipple fluid aspirates both in clinical practice and in breast cancer research. Diagn. Cytopathol. 2016;44:670-675. © 2016 Wiley Periodicals, Inc.