Overexpression of NM23-H1 in MDA-MB-435 breast carcinoma cells resulted in decreased activated MAPK (pMAPK) levels without affecting the level of total MAPK, suggesting that NM23-H1 inhibits Ras/MAPK signaling through KSR phosphorylation and inactivation [14]. This evidence concerns the gene KSR1 and breast carcinoma.