Abstract 5757: Study of human mammary tumor virus (HMTV) in human breast cancer by NanoString nCounter and FISH analysis

Abstract

Abstract Human Mammary Tumor Virus (HMTV), a retrovirus 90-98% homologous to Mouse Mammary tumor Virus (MMTV), the etiological agent of murine mammary cancer, has been detected by PCR in 40% of American women’s breast cancers, but not in healthy tissues of the same breast (Cancer Research 1995, 55:5173-79; Clin. Cancer Research 2001, 7-283-4). A complete 9.9 kb HMTV proviral sequence has been detected in breast cancer genomic DNA (Cancer Res 2001,61:1754-9). HMTV viral particles with betaretrovirus characteristics have been isolated from metastatic breast cancer cells in effusions (MSSM cells). Expression of HMTV proteins has been detected in MSSM cells by western blot, fluorescence-activated cell sorting analysis, and immunofluorescence assays but not in normal mammary epithelial cells (J Virol Methods 2010, 163(1): 157-61). PCR is a sensitive technique susceptible of contamination, which due to amplification, could result in false positive detection. Although murine DNA was not found by PCR, the possibility still exists that HMTV in human DNA could be a result of laboratory contamination. Despite the substantial evidence supporting the presence of HMTV in breast cancer the controversy continues because the chance of contamination has led to doubt that murine-like viruses are human pathogens. We now report additional analyses of breast cancer specimens employing other methods for HMTV detection that reinforce previous findings. NanoString nCounter, a new technology using specific 100 mer oligonucleotides as probes bound to reporter molecules that can detect HMTV gag, env and LTR sequences as well as two murine specific probes in a single reaction without amplification. Flourescence in situ hybridization (FISH) assays with a HMTV probe is a technology that permits visualization of HMTV proviral DNA in the nuclei of surgical samples of breast cancer as well as in MSSM cells. Results from Nanostring nCounter, and FISH analysis show the presence of HMTV DNA in surgical cancer specimens and in MSSM cells. The data exclude contamination and confirm the authenticity of HMTV in human breast cancer. Next-generation sequencing and other studies are in progress to determine the role of HMTV in the pathogenesis of breast carcinoma. Citation Format: Stella M. Melana, Joseph Tripodi, Digna Nosike, Jaffer Shabnam, Polly Etkind, Beatriz GT Pogo, James F. Holland. Study of human mammary tumor virus (HMTV) in human breast cancer by NanoString nCounter and FISH analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5757. doi:10.1158/1538-7445.AM2017-5757