Low prevalence of human mammary tumor virus (HMTV) in breast cancer patients from Myanmar

Thar Htet San,Ngu Wah Min,Toshiaki Ohara,Soichiro Fushimi,Ohnmar Kyaw,Masayoshi Fujisawa,Teizo Yoshimura,Xu Yang,Akihiro Matsukawa,Lamin Soe

doi:10.1186/s13027-017-0130-0

Abstract

BackgroundHuman mammary tumor virus (HMTV) is 90–95% homologous to mouse mammary tumor virus (MMTV), one of the causal agents of murine mammary tumors. HMTV (MMTV-like) sequences were reported to be present in human breast cancers from several populations with a prevalence range of 0–78%; however, the prevalence of HMTV in breast cancers from Myanmar remains unknown.MethodsFifty-eight breast cancer samples from Myanmar women were examined in this study. DNA was isolated from formalin-fixed paraffin-embedded specimens, and HMTV envelope sequences were detected by semi-nested PCR. The sequence of the PCR products was also confirmed.ResultsOnly 1.7% (1 of 58) of the breast cancers were positive for HMTV, and the sequence of PCR products was 98.9% identical to the reference HMTV sequence (GenBank accession No. AF243039). The tumor with HMTV was grade III invasive ductal carcinoma, 7.0 cm in size with lymph node metastasis (T3, N1, M0).ConclusionsWe, for the first time, investigated the presence of HMTV in Myanmar breast cancer patients. In accordance with other Asian studies, the prevalence of HMTV in Myanmar was quite low, supporting the hypothesis that Asian breast cancers have different etiologies than in Western countries, where HMTV is more prevalent.

Highlights

Human mammary tumor virus (HMTV) is 90–95% homologous to mouse mammary tumor virus (MMTV), one of the causal agents of murine mammary tumors
Mouse mammary tumor virus (MMTV) is a non-acute transforming type B retrovirus that causes the majority of mammary tumors in mice
MMTV-like sequences were found in breast tissues prior to the development of virus-positive breast cancer, indicating a

Summary

Introduction

Human mammary tumor virus (HMTV) is 90–95% homologous to mouse mammary tumor virus (MMTV), one of the causal agents of murine mammary tumors. The incidence of breast cancer is higher in developed countries, while the mortality is higher in developing countries These discrepancies in incidence and mortality are attributed to early detection as well as risk factors including geographic variation, racial/ethnic background, genetic variation, lifestyle, and reproductive patterns associated with urbanization and economic development [3, 4]. In 1995, retroviral sequences 90–95% homologous to MMTV were detected in 39% of human breast cancers in the United States [9]. A 9.9-kb proviral structure, which was 95% homologous to MMTV, was successfully amplified from two distinct human breast cancers. The retrovirus with MMTV-like sequence was subsequently designated human mammary tumor virus (HMTV) [10]. MMTV-like sequences were found in breast tissues prior to the development of virus-positive breast cancer, indicating a

Objectives

Methods

Results

Discussion

Conclusion