NOP14 and breast cancer: Moreover, all the nude mice developed tumor after subcutaneous inoculation with MDA-MB-231 cells carrying the empty vector (n = 11), while no tumors formation were observed in mice inoculated with MDA-MB-231 cells overexpressing NOP14 (n = 10) (Figure 2E), suggesting that up-regulation of NOP14 inhibits tumorigenesis in xenograft mouse models of breast cancer.