The functional importance of Sp1, Sp3 and Sp4 in cancer cells has been confirmed by RNA interference (RNAi) showing that knockdown of Sp transcription factors Sp1, Sp3 and Sp4 (singly or combined) decreases cell proliferation, survival, angiogenesis and inflammation [26, 35, 36, 42]. The gene discussed is SP1; the disease is cancer.