FIG. 9.

Runx1 deletion impairs chemically induced skin tumorigenesis. (A) DMBA/TPA treatment of WT and K14Cre × Runx1^fl/fl (cKO) littermate mice, shown on the timeline schematic of hair cycle phases. (B) Starting at 8 weeks of treatment, cKO mice showed fewer papillomas than WT mice. (C) Average numbers of tumors (top) and fractions of tumor-bearing mice (bottom) measured weekly as a function of time of TPA treatment (in weeks) for mice treated with DMBA at three different stages as indicated on the right. Note the reduction in tumor formation in cKO versus WT mice at comparable stages. P values noted as p^A (top) and p^F (bottom) for each stage of initiation are shown for data after 15 weeks of TPA treatment. (D) Number of tumors/mouse averaged among the three stages of initiation (n = 24 cKO and 28 WT mice). (E) Number of hair cycles, estimated by the frequency of skin color change from pink to black in mice initiated with DMBA and treated with TPA for 15 weeks.