Fig. 2
From: Estrogen promotes estrogen receptor negative BRCA1-deficient tumor initiation and progression
Estrogen promotes Brca1-deficient mammary tumor metastasis. a-d We inoculated 1 × 106 metastatic p18−/−;Brca1MGKO tumor (donor B) cells into the mammary fat pads of 4-week-old female NSG mice in which either E2 or placebo Beeswax pellet was implanted subcutaneously. When newly generated tumors reached maximum size (1.3 cm3) allowed by the IACUC in 3–6 weeks, or the mice became moribund, lungs were examined for gross appearance (a), H.E. staining (b), and quantification of the number of metastatic nodules (c). M, metastatic nodules. Data in (c) are mean ± SD for the numbers of metastatic nodules detected in all lobes of the lungs in each group (n = 4). d Representative immunohistochemical analysis of lung metastasis with antibodies against estrogen receptor (ER)α, p-fos-related antigen 1 (Fra1), and vimentin (Vim)