High prevalence of mouse mammary tumor virus-like gene sequences in breast cancer samples of Iranian women.

Mouse mammary tumor virus (MMTV) is considered to be responsible for breast tumor development in mice. In several instances sequences homologous to the genome of this virus have been reported in human breast cancer samples. Here we aimed to evaluate MMTV involvement in human breast cancer development. DNA was extracted from 118 formalin fixed and paraffin embedded malignant (n = 59) and benign (n = 59) breast lesions. Using two sets of outer and inner MMTV-like envelope specific primers, in a nested PCR setup, MMTV genome was detected in 19 samples out of 59 (%32.2) cases of breast carcinomas, while in non-malignant breast tissue samples, only 3 samples out of 59 (%5) were positive. The difference was statistically highly significant (p < 0.001). Alignment of PCR amplified sequences with BR6, GR and C3H mouse mammary tumor virus strains emerged to be around 99% identical which is indicative of tumor tissue infection by an exogenous mouse MMTV genome.

Prevalence of human papilloma virus among women with breast cancer since 2005-2009 in Isfahan.

BACKGROUND: Human papilloma virus (HPV) DNA has been detected in breast carcinoma by different laboratorial techniques, suggesting that the virus could play a role in the pathogenesis of this tumor. MATERIALS AND METHODS: It was a descriptive study. Systematic random sampling was used for selecting 55 cases of breast cancer and 51 controls of benign breast lesions from the file of Seyedshohada hospital of Isfahan since 2005-2009. A total of 106 paraffin-embedded specimens were selected and HPV DNA was analyzed by polymerase chain reaction and sequenced for different types of HPV in case of positivity for HPV DNA. Data analysis was performed by SPSS 16 software using descriptive statistic, Chi-square, and Fisher's exact tests. RESULTS: Out of 55 malignant and 51 benign breast specimens, 18.2% (10) and 13.7% (7) were positive to HPV DNA, respectively (P = 0.53); 70% (7) malignant and 43% (3) benign breast specimens were positive to high-risk HPV genotypes. In malignant specimens, the most common high- and low-risk genotypes were HPV-16 (3.6%) and HPV-11 (3.6%), respectively. In benign specimens, the most common high- and low-risk genotypes were HPV-31 (3.9%) and HPV-43 (3.9%), respectively. Among malignant and benign specimens, ductal carcinoma and fibro adenoma were the most common lesions positive to different types of HPV, respectively. CONCLUSION: This study demonstrated the presence of HPV genome in both malignant and benign tumor tissues in women with breast lesions in Isfahan; therefore, further larger epidemiologic studies need to be analyzed to establish the exact role of this virus in the pathogenesis of breast cancer.