We also observed that 4-HPR was able to interfere with pro-survival pathways, including MAPK and STAT-3 signaling, down-regulating the expression levels of both P-ERK-1/2 and STAT-3 (Fig 3E, 3F, 3G and 3H), suggesting that the effects on caspases are not the only mechanism through which fenretinide exerts its anti-tumor activity. This evidence concerns the gene STAT3 and neoplasm.