Diseases
Mouse virus may cause breast cancer in humans
By Ben Wasserman
Apr 29, 2008 - 4:33:19 PM

TUESDAY April 29, 2008 (foodconsumer.org) -- One study published in the June 15, 2008 issue of International Journal of Cancer confirms that mouse mammary tumor virus (MMTV) is common in human breast cancer tissue.

MMTV has been known to cause breast cancer in mice.  Early studies have found that MMTV-like envelope gene or env sequences in up to 74 percent of human breast cancers.

In the current study, Mok MT and colleagues from the University of New South Wales in Sydney, Australia found MMTV-like env sequence in 56 percent of Australian breast cancer specimens and 87.5 percent human breast cancer cell lines.

The study also identified the locus of MMTV-like env sequence in human cells.

The researchers write "The MMTV-like env sequence was shown to be distinct from the human endogenous retroviral sequences and is closely related to rodents."

Mouse mammary tumor virus (MMTV) is a milk transmitted retrovirus, according to wikipedia.  Some strains of mice carry this virus while it can also spread from mother to offspring via milk.  The tumor in mice caused by the virus is generally benign.

One study reported in Medical Oncology. 20(3):233-6, 2003 showed 62 percent of gestational breast cancer and 38 percent of all breast cancers contain MMTV or MMTV like sequence.

The virus readily infects canine and feline tissue culture cells.  According to one theory, humans may get the virus through pets.