Fig. 2.

Estrogen increases circulating tumor cells in mice bearing xenograft tumors and enhances the survival and lung seeding of intravenously injected Tsc2-null cells. (A) DNA prepared from the blood of placebo (n = 3) and E₂-treated (n = 3) mice bearing xenograft tumors of similar size (≈1,000 mm³) was analyzed by real-time PCR using rat-specific primers to quantitate circulating tumor cells. (B) Levels of circulating tumor cell DNA 6 h after i.v. injection of ELT3 cells into placebo (n = 3) and E₂-treated (n = 3) mice. (C) Levels of tumor cell DNA in the lungs 24 h after i.v. injection of ELT3 cells into placebo (n = 3) and E₂-treated (n = 3) mice. *, P < 0.05, Student's t test.