Figure 4.

Serial passage facilitates growth of tumors implanted in either brain or mammary fat pad. Brain metastasis of one triple negative breast cancer patient was used for this experiment. Tumor was prepared with the mincing method for implantation (1 µL tumor + 2 µL phosphate-buffered saline) in mouse brain or mammary fat pad with the Pipette or Forceps method, respectively. Implantation was in either brain (A) or mammary fat pad (B). Implanted tumors were repeatedly passaged three times with the same site used for implantation. Engraftment rate at 8 weeks (w) after implantation, and growth of engrafted tumors over time (mean and standard error) as measured with magnetic resonance imaging (A) or calipers (B) are shown for tumors before first passage (B0 or M0) and after third passage (B3 or M3). P values in standard t tests for group comparison are indicated (* ≤ 0.05).