HOXA9 and neoplasm: Moreover, IGF1 has been described as a growth-regulatory MLL-ENL/Hoxa9/Meis1 target and as a direct C/EBPβ target gene involved in autocrine stimulation of transformed murine monocytes and in neoplasia (Pollak et al, 2004; Wessells et al, 2004; Steger et al, 2015; Collins & Hess, 2016b).