DNA promoter hypermethylation in nipple fluid: a potential tool for early breast cancer detection

// Jolien S. de Groot 1 , Cathy B. Moelans 1 , Sjoerd G. Elias 2 , Mary Jo Fackler 3 , Robert van Domselaar 1 , Karijn P.M. Suijkerbuijk 1 , Arjen J. Witkamp 4 , Saraswati Sukumar 3 , Paul J. van Diest 1 , Elsken van der Wall 5 1 Department of Pathology, University Medical Center Utrecht, Utrecht, The Netherlands 2 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands 3 Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, USA 4 Department of Surgery, University Medical Center Utrecht, Utrecht, The Netherlands 5 Department of Medical Oncology, University Medical Center Utrecht, Utrecht, The Netherlands Correspondence to: Elsken van der Wall, e-mail: e.vanderwall@umcutrecht.nl Keywords: nipple fluid, methylation, breast cancer Received: December 10, 2015     Accepted: February 29, 2016     Published: March 25, 2016 ABSTRACT Introduction : Nipple fluid aspiration provides direct non-invasive sampling of fluid from the mammary ductal system, where the majority of breast cancers originate. DNA promoter hypermethylation (“methylation”) occurs early and at high frequency in breast carcinogenesis, bearing the potential as a biomarker for cancer detection at its earliest stages. We assessed methylation in nipple fluid from breasts of healthy women, of women with sporadic breast cancer and of their contralateral breasts. Our goal was to investigate whether nipple fluid can be used as a reliable methylation biomarker source. Methods : Methylation levels of 13 genes were analysed by quantitative multiplex-methylation specific PCR (QM-MSP) in nipple fluid samples from breasts of healthy women, and from the affected and contralateral breasts of breast cancer patients. Results : Methylation analysis of the low-volume nipple fluid samples was feasible. Despite the generally low methylation levels, cancerous and healthy breasts nipple fluid could be discriminated with an area under the receiver operating characteristic curve (AUC) of 0.64 (p<0.01) based on a multivariate model including AKR1B1, ALX1, RASSF1A and TM6SF1 . Within-patient differences between cancerous and contralateral nipple fluid samples were less prominent. Conclusions : Cancerous nipple fluid contains increased levels of methylation of tumor suppressor genes that potentially could serve as a biomarker for early breast cancer detection.