They found that CDCA8/Borealin expression was repressed by high levels of p53 in human colorectal carcinoma cell lines, and Rb family proteins are involved in the downregulation of CDCA8 in response to high p53 signaling [89]; however, the authors noted that p53 was not the sole factor regulating CDCA8 expression and that other unknown transcription factors were likely also involved [95]. This evidence concerns the gene TP53 and colorectal carcinoma.