Dear Dr. Sohini Sen
Injecting MCF-7 alone will not develop cancer in mice. It must be supplemented with estrogen.
MCF-7 is an estrogen dependent cell line. So, formation of tumors from MCF-7 cells implanted in nude mice is dependent on the presence of estrogen. For a proper tumor growth, the presence of estrogen is essential and therefore to maintain the level of hormone, estrogen must be supplied externally in the form of pellets.
You may mix MCF-7 cell suspension and Matrigel in the ratio (1:1) to make up a volume of 100ul before injection. This will help to increase the pick-up rate, uniformity, and growth rate of tumor as it will give support in angiogenesis. Administration of estrogen (s.c. pellet of 17 beta-estradiol and estrone in drinking water, 0.5 mg/l) to nude mice may result in sustained growth of MCF-7 tumors. Tumor formation may be observed within 5-6 weeks of inoculation.
Regards,
Malcolm Nobre
