Of interest, we also observed that over expression of a DHFR specific siRNA (siDHFR) down-regulated DHFR levels by threefold as compared to Oligofectamine alone transfected cells (Fig. 4A), and also reduced anchorage-dependent growth of the HCT-116 colorectal cancer cell line by approximately two fold (Fig. 4D); these data suggest that changes in DHFR levels are directly associated with cell proliferation. The gene discussed is DHFR; the disease is colorectal cancer.