While the precise relationship between DAB2IP and RAB40C, and their inter-relationships with Arf6 and Ras, await further investigation, this study warrants our reconsideration of how we perceive DAB2IP as a tumor suppressor and RAB40C as regulator of LD homeostasis, and how we classify GAPs with their small GTPases. This evidence concerns the gene RAB40C and neoplasm.