Figure 3

Fibroblast growth factor receptor (FGFR)4 deficiency delayed pathological development of breast tumors. Mammary gland lesions were identified in the breast tumor tissue sections from the MMTV-TGFα transgenic (Tg) and FGFR4^−/−: MMTV-TGFα bigenic (KO-Tg) mouse groups and compared at a similar age of 6 months. Most of the breasts or palpable tumor nodes from the KO-Tg group were found in lower grades including the usual duct hyperplasia (UDH) (A), lobular carcinoma in situ (LCIS) (B), and duct carcinoma in situ (DCIS) (C); while at a comparable age they were in higher grade of UDH (E), invasive lobular carcinoma (F) and invasive duct carcinoma (G, H) in the Tg group. This is in contrast to breasts from wild-type mice with the typical duct and lobular structures surrounded by adipocytes (D). Micrographs are representative of about 312 and 288 samples or sections from the Tg and KO-Tg groups, respectively.