In accordance with the notion that the tumor suppressing activity of KLF2 is exerted at least in part by controlling RA signaling, ectopic expression of this factor, similarly to direct alteration of the FABP/CRABP2 ratio, converted RA from a pro- to an anti-proliferative agent (Figure 6B, Figure S3C). Here, CRABP2 is linked to neoplasm.