Abstract 2302: Detection of HMTV env sequences in hormonally dependent tissues

Abstract

Abstract Breast cancers discovered during pregnancy or lactation (gestational) are known to be very aggressive and of poor prognosis. We have found a Mouse Mammary Tumor Virus (MMTV) like virus in human breast cancer, but not in adjacent normal tissue, indicating it exogenous origin. This virus, Human Mammary Tumor Virus (HMTV) recognized by its unique env sequence is present in 62% of gestational breast cancer, compared with 38% of sporadic breast cancers (Wang et al, 2003. Medical Oncology 20:233-236). The aggressive phenotype of gestational breast cancer was suggested to be due to the effect of hormones that stimulate cellular growth. HMTV- LTR contained sequences which are responsive to several hormones (glucocorticoid, estrogen, prolactin, and progesterone) and a transcription factor (TEF-1 family) (Wang et al, 2003. Medical Oncology 20:233-236). To find if HMTV is present in other tissues that respond to hormones, we have investigated the presence of HMTV sequences in two of these tissues. Endometrium is a classical example of such tissue. Endometrial cancers and normal endometrium were analyzed for HMTV env sequences. The results indicated that HMTV env sequences were present in 3.4% of the normal tissues and 37% of the tumors analyzed. Recently, it was reported that MMTV-like sequence was found in 10% of endometrial cancers (Johal et al. 2010, J. Med. Virology; 82: 1044-50). During lactation, the mammary gland experiences major metabolic changes due to hormonal stimulation. We have examined 88 normal milks and 63 milks from women, who have undergone biopsies. Whereas in the cells of normal milks 8% showed env sequences cells in the milk of the biopsied group showed that 23.8% contain HMTV sequences. These results confirmed electron microscope observations that a betaretrovirus was present in milk from healthy women and those with breast cancer (Moore et al. 1971, Nature 229: 611-615). Taken together, the results presented here suggest that tissues and tumors stimulated by hormones showed high prevalence of HMTV sequences. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2302. doi:10.1158/1538-7445.AM2011-2302