Hello Zhang Zhang

MCF-7 cells are a slow growing estrogen receptor (ER) positive human breast cancer cell line that is commonly used to model estrogen responsive breast cancer cell growth in-vitro and tumour growth in-vivo. Hormone responsive tumors can be formed in the athymic mouse using MCF-7 cells, but due to the low ovarian estrogen production, tumor growth can be induced with estradiol supplementation. Estrogen improves the take rates of ER positive tumors in immunocompromised mice.

However, low dose estradiol should be provided to support the growth of MCF7 tumor in immune compromised mice over a period of 5-6 weeks, without any complicated side-effects.

Without estrogen supplementation, MCF-7 cells may form slow growing tumors and may not induce metastasis in mice.

Best.

The growth and proliferation of MCF7 cells are often dependent on exogenous estrogen, and it is generally believed that the presence of estrogen is required for tumorigenesis in female nude mice.

In nude mice, the absence of functional ovaries and adrenal glands can lead to a deficiency in estrogen, which can impact the growth and proliferation of MCF7 cells. To compensate for this deficiency, exogenous estrogen can be supply in the form of 17β-estradiol to the mice.

Good Luck.