These findings suggest that the RKO cell-secreted factor(s) likely include active TGFβ1, since CRC cells are known to secrete this cytokine [20], [40] and the TGFβ1 neutralizing antibodies produced an effect similar to CM from RKO cells expressing the km23-1 siRNAs. The gene discussed is TGFB1; the disease is colorectal carcinoma.