The other group of ACC tumors express neither MYB nor MYBL1 and also do not express EN1 or SOX4. Instead, they express oncogenic transcription factors KLF4, FOXO1, JUNB and FOSB and the important developmental regulator VGLL3. There is currently no other supporting evidence indicating that the products of these genes act as drivers of tumorigenesis in this subgroup of ACC tumors, but they seem like excellent candidates for further study and perhaps the development of animal models to test their activities. This evidence concerns the gene KLF4 and adrenal cortex carcinoma.