The Mammary Gland Microenvironment Directs Progenitor Cell Fate In Vivo

Table 1

Number of positive outgrowths from mammary glands divested of epithelium and inoculated with various amounts of untreated or Tamoxifen-treated Itgβ1^fx/fx, CreER Cells.

No. of inoculated cells	Untreated (control)	Treated with Tamoxifen
50,000	2/4	1/4
100,000	1/2	0/4
500,000	1/1	0/1
Total	4/7	1/9