We investigated the expression of 10 genes (the top 11 hits except BRAF, see Table 1), in the normal (Nthy-ori 3–1) and tumor (BCPAP) cell lines used for the siRNA library screening, as well as in a panel of thyroid tumor cell lines, representative of different tumor histotypes, and/or carrying different oncogenes: PTC-derived (TPC-1, carrying the RET/PTC1 oncogene); FTC-derived (WRO82–1); ATC-derived (8505C and HTC/C3, carrying the BRAFV600E oncogene; KAT-18). This evidence concerns the gene RET and thyroid tumor.