In contrast, in SOX4-knockdown HCT-116 and HT-29 cells, which were established by lentivirus gene delivery (Additional file 1: Fig. S4), a significant reduction in HDAC1 protein level was observed (Fig. 3c), indicating that HDAC1 is positively regulated by SOX4 in CRC cells. The gene discussed is HDAC1; the disease is colorectal carcinoma.