Down-regulation of CHD5 mRNA expression in breast cancer. (A) Expression of CHD5 mRNA in breast cancer cell lines and primary culture of human mammary epithelial cells (HMEC), as detected by real-time RT-PCR. GAPDH was used for normalization. The ratio CHD5/GAPDH in HMEC was defined as 1, and the ratio in other cell lines was adjusted accordingly. (B) Detection of CHD5 protein expression in six breast cancer cell lines and in HMEC cells by Western blotting. Actin was used as a loading control. (C) Representative results of CHD5 mRNA expression in breast cancer samples and matched normal tissues, as detected by real-time RT-PCR using HMEC as a positive control. The ratio of CHD5/GAPDH in HMEC was defined as 1, and that in other samples were normalized accordingly. (D) The distribution of CHD5 mRNA expression values in the tumor group (n = 58) versus that in the normal group (n = 58) are shown in the plot-box diagram. The box ranges from the 25th to the 75th percentile, and the bold line across the box indicates the median. The whiskers are 1.5 times of the quartile values.