Fig. 5. Jak2 deficiency leads to lack of Stat5 activation but not expression of ERα and Cyclin D1.

(a) Immunohistochemistry to assess the PRL-mediated activation of Stat5 in control tumors and cancers lacking Jak2. Insets show the PRL-induced activation of Stat5 in normal #3 mammary glands derived from the tumor-bearing, wildtype recipient females. (b) Immunohistochemistry to determine the continuous expression of ERα and Cyclin D1 (Ccnd1) in PRL-induced mammary cancers that lack Jak2 and their wildtype controls. All slides were counterstained with hematoxylin (bars, 50 μm).