Molecular Studies on env Gene of Mouse Mammary Tumor Virus in Human Breast Cancer

Abstract

newline Background: The exact cause an etiological factor responsible for breast cancer still remains elusive. The discovery of Mouse Mammary Tumor Virus (MMTV) as a causal agent for mammary cancers in mice led the scientific community to put forth the plausibility that, a virus may cause human breast cancer. Many studies regarding the involvement of MMTV in human breast cancer have been reported using sophisticated, sensitive and specific molecular techniques from around the world. Different rates of detection of MMTV-like virus (MMTV-LV) in human breast cancer have been noted in various populations. There is a need to explore the role of MMTV in Indian population which has the third highest number incidence and highest cases of mortality related to breast cancer. newlineObjectives: The main objectives of this study are to identify MMTV like gene sequences in human breast cancer and to estimate the frequency of breast cancer linked to MMTV infection. newlineMethodology: Surgical tissue biopsy samples (cancer tumor and adjacent normal breast tissue) were collected from 132 breast cancer patients. MMTV env and SAG LTR region specific primers were used for the PCR based detection of these sequences in the clinical specimens. MCF-7 cell line and 2.7 kb DNA fragment comprising env and SAG LTR sequences (GenBank AF243039) were used as positive controls. Microarray based gene expression profiling which included the env and gag genes of MMTV was done for 13 cancer and 3 normal breast tissue samples. newlineResults: No PCR amplification of targeted MMTV sequences was obtained in genomic DNA of MCF7 cells. The semi nested PCR for MMTV env sequences and SAG LTR region using specific primers did not produce any amplification in the clinical samples. The filter probesets by expression and flag call reports indicate that there were no detectable signals for MMTV specific probes. Both PCR and Microarray results indicate the absence of these sequences in the current study specimens. newlineConclusion: Considering the results of detection of MMTV-LS