Prevalence of HMTV in breast carcinomas and unaffected tissue from Mexican women.

BACKGROUND: Breast cancer is a complex multifactorial genetic disease. Among other factors, race and, to an even greater extent, viruses are known to influence the development of this heterogeneous disease. It has been reported that MMTV-like (HMTV) gene sequences with a 90 to 98% homology to mouse mammary tumor virus are found in several populations with a prevalence range of 0 to 74%. In the Mexican population, 4.2% of patients with breast cancer exhibit the presence of HMTV (MMTV-like) sequences. The aim of this study was to evaluate the presence and current prevalence of retroviral HMTV (MMTV-like) sequences in breast cancer in Mexican women. METHODS: We used nested PCR and real-time PCR with a TaqMan probe. As a positive control, we used the C3H MMTV strain inserted into pBR322 plasmid. To confirm that we had identified the HMTV sequences, we sequenced the amplicons and compared these sequences with those of MMTV and HMTV (GenBank AF033807 and AF346816). RESULTS: A total of 12.4% of breast tumors were HMTV-positive, and 15.7% of the unaffected tissue samples from 458 patients were HMTV-positive. A total of 8.3% of the patients had both HMTV-positive tumor and adjacent tissues. The HMTV-positive samples presented 98% similarity to the reported HMTV sequence. CONCLUSIONS: These results confirm that the HMTV sequence is present in breast tumors and non-affected tissues in the Mexican population. HMTV should be considered a prominent causative agent of breast cancer.

[Survival of breast cancer patients treated with inhibitors of the aromatase vs tamoxifen]. / Supervivencia de pacientes con cáncer de mama tratadas con inhibidores de la aromatización vs tamoxifeno.

BACKGROUND: In Mexico the breast cancer occupies the second place as cause of death by oncological illness and the etiology is considered multifactorial. The systemic treatment of this cancer is necessarily after the surgery and simultaneously when radiotherapy is used; therefore the recent introduction of newly non toxics and efficient antiestrogens which block the effect of estrogens from circulation have become drugs of first line in the metastasis illness. OBJECTIVE: To compare the clinical evolution and the survival of patients with locally advanced breast cancer and metastasis with the use of two therapeutic modalities. MATERIAL AND METHODS: Under informed consent 20 patients with diagnosis of breast cancer and out of oncological therapeutic processing were included. Randomly an inhibitor of the aromatase (anastrozole, 1 mg for day) was used in 10 patients and in the other 10 patients tamoxifen (20 mg for day) both for 2 years, subject to verification of positive estrogens-progesterone receptors. RESULTS: Half of the patients of each group had a clinical stage III. The most frequent histological diagnosis was the ductal carcinoma in 70% of the group with tamoxifen use, while in anastrozole group was 90%; the mastectomy prior to the tamoxifen was carried out in 60% of the patients and in 50% of the group with anastrozole. The acceptable response to the processing in the patients with tamoxifen was complete in the 60% of the cases, but with the use of anastrozole was 80%; survival in the group with anastrozole was of 100% in two years of follow up, while in women that received tamoxifen the survival was 90% (p<0.001). CONCLUSIONS: The use of anastrozole improved the survival as well as the quality of life, showing no side effects in this group of patients.