Fig. 9. MTA1 transgenic mice develop mammary gland hyperplasia, hyperplastic nodules and mammary tumors. (A) Hematoxylin and Eosin staining showing ductal hyperplasia in mammary glands from 6 weeks virgin MTA1-transgenic mice. Pleomophic nuclei and mitotic figures are present (arrows). (B) MTA1-TG mammary glands after one pregnancy showed intra-luminal focal hyperplasia. Note the ductal epithelial cells contain multilayers and protrude into the lumen (arrows). (C) Founder mice line 30 with single large mammary tumor on the thoracic mammary gland. (D) Founder mice line 31 with a single large tumor on the thoracic mammary gland. (E) Whole-mount staining of number 4 right inguinal mammary glands from 18-month-old virgin MTA1 transgenic glands with several hyperplastic nodules (arrows). (F) Hematoxylin and Eosin-stained section of mammary adenocarcinoma in a 15-month-old multiparous MTA1-TG female. (G) Hematoxylin and Eosin-stained section of malignant lymphomas in a 24-month-old multiparous MTA1 transgenic mammary gland. (H) Western blot analysis of cyclin D1 and Bcl-X_L in mammary tumors from MTA1 transgenic mice (T1, T2) and wild-type mouse mammary tissue (WT). The blot was reprobed with T7 antibody to show transgene expression. Vinculin was used as a loading control.