CCDC170 and breast cancer: Furthermore, whether CCDC170 was overexpressed transiently (P = 0.001; Figure 5J) or stably (P = 0.003; Figure 5K) in MCF7 breast cancer cells, the cell viability was significantly lower than that of the control group in a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.