Most of them encode proteins involved in fundamental processes, and some, such as the kinases PLK1, WEE1, AURKB and several proteasome subunits, have previously been shown to be essential for cell survival, emerging as top-ranking lethal hits in RNAi-mediated phenotypic proliferation screens in different tumor cell lines [14, 17, 18]. This evidence concerns the gene PLK1 and neoplasm.