As shown in Fig. 2c, d and Additional file 1: Fig. S1b, c, the results from LDA assay showed that the frequencies of both in vitro sphere-forming cells and in vivo tumor-initiating cells were significantly increased by SOX4 overexpression, which confirms that SOX4 enhances the sphere-forming and self-renewal capacities of CRC cells. The gene discussed is SOX4; the disease is colorectal carcinoma.