[Lani]

many risks of breast cancer are found to affect the female child of a mother exposed and there are many exposures in childhood, during puberty etc.

Mouse dropping exposure is ubiquitous. Anyone who picks something off from the floor, even a floor that has never had a mouse run over it...unless in a Japanese household... has probably been exposed to virus shed from mice which was carried in on shoes worn outdoors.

At ASCO, they showed that the incidence of breast cancer was similar with the population distribution of a certain type of rat. Other types of rats supposedly were not affected by MMTV and those other types of rats had a different geographic distribution (Asia, Australia, etc),. That is certainly not evidence of cause and effect.

Perhaps it is the combination of a genetic variation/defect in the patient combined with the MMTV infection.

Noone knows. But I would not look only for macro(large) scopic sources of mouse contamination but also for microscopic ones and much much further back than one or two decades.

When clockface painters who used radioactive paint (and licked their brushes) were found to have higher rates of cancer of the tongue and mouth, it was four or more decades later as I recall. DES exposure effects take two/three/four decades and more to manifest if I remember right.

Just food for thought