Figure 2. TNF-α–adapted Fancc^–/– stem cells are preleukemic.

(A) 1 × 10⁶ untreated WT, Fancc^–/–, TNF-α–treated (10 days) WT or outgrown (30 days) Fancc^–/– BM cells (along with 1 × 10⁶ competitive cells) were injected i.v. into lethally irradiated recipients. Survival of recipient mice was quantified by Kaplan-Meier analysis. Experiments were performed 3 times, each with 4 recipient mice (total 12 mice per group). Data were obtained from recipient mice transplanted with cells from 1 culture. We performed BM transplantation with 5 separate cultures, which gave similar results. (B) Increased blast cells in BM and peripheral blood and massive splenomegaly in Fancc^–/– leukemic mice. (C) Elevated expression of myeloid markers in Fancc^–/– leukemic mice. (D) H&E staining of tissue sections of recipient mice transplanted with TNF-α–treated WT or Fancc^–/– BM cells. Original magnification, ×10. (E) Clonal origin of a preleukemic clone. LM-PCR was performed to determine the retroviral integration pattern in animals transplanted with outgrown Fancc^–/– cells transduced with control (enhanced GFP) vector. BM cells from animals 1–6 presented with an identical retroviral integration pattern, indicating that the repopulating cells were clonal in origin. The internal vector control was detectable at 200 bp in animals 1–6 and confirmed a functional LM-PCR reaction. M, marker; W, water.