When Braf CA/+PtenΔ/+Sox2fl/fl, Braf CA/+PtenΔ/+Sox2fl/+, Braf CA/+PtenΔ/+Sox2+/+ mice were treated with tamoxifen at p2-4, a marked Sox2 gene dosage-dependent decrease in tumor incidence was observed (Fig. 3f, Fig. S7F). The gene discussed is SOX2; the disease is neoplasm.