Noninvasive mammary intraepithelial lesions (IELs) in humans are detected with increasing frequency because of
routine mammographic screening. The presence of IELs may herald increased risk of developing invasive breast
carcinoma in women. An animal model is needed to study breast cancer and spontaneous IELS. This study describes
the histologic and immunohistochemical similarity between human and canine IELs
