Mouse mammary tumor virus-like gene sequences in breast cancer samples of Mexican women

Background: Previous reports related the presence of mouse mammary tumor virus (MMTV)-like gene sequences to human breast carcinoma. The aim of this study was to determine whether MMTV-like env gene sequences are present in breast cancer samples of Mexican women and in breast and lung cancer cell lines. Methods: Using specific primers for MMTV, we tested 3 breast cancer cell lines, 4 non-small lung cancer cell lines and 119 breast cancer samples from Mexican women. Results: MMTV-like gene sequences were amplified in the lung cancer cell INER-51, but not in the MCF-7 cell line that has been used as a positive control in other reports and in 5 of 119 (4.2%) breast cancer biopsy tissues. Furthermore, the identity of sequences of PCR products from INER-51 and a breast cancer-positive sample are 98 and 99% when compared with the env region of MMTV (GenBank accession No. AY161347). Conclusion: These results indicate that MMTV-like gene sequences are present in the Mexican population.