TF and cancer: One of the FOX proteins, FOXR2, has been identified as an oncogene, a gene that can cause cancer when mutated or overexpressed, which promotes the development of some cancers [7] FOXR2 is located on the X chromosome at Xp11.21 (Fig. 1A) and encodes a TF that is normally expressed only in the testis (Fig. 1B).