NFIB and adrenal cortex carcinoma: Figure 2C shows the fold activation of the promoters by ectopically expressed Myb proteins relative to no Myb protein. We found both MYB promoters were activated similarly (4 to 7-fold) by full-length Myb and a Myb-Nfib fusion protein (T349, Figure 2C) [8]. The two MYB promoters were not significantly activated by a mutated Myb transcription factor harboring a point mutation that disrupts DNA-binding activity [27]. These data demonstrate that Myb transcription factors are capable of activating both MYB gene promoters, which could create stimulatory feedback loops in ACC tumors.