CAFC-survival after conditioning with 5-FU and KL. Mice (2 to 3 per group) were treated with two weekly doses of saline, 5-FU, or 5-FU + KL, and killed 24 hours after the last 5-FU dose to test CAFC-survival. (A) Residual CAFC per hind limb; (B) the percentage of surviving CAFC relative to control (saline treated) both as a function of CAFC-day type. Early CAFC (day 7) correlate with committed progenitors like CFU-S day 8 and late CAFC (day 28 and later correlate with long-term repopulating stem cells (LTRA).31 (▪), control marrow; (♦), 5-FU marrow; (•), 5-FU + KL.