HES1 and metastatic prostate carcinoma: Although the results of immunohistochemical analysis show mere correlations between high PTOV1 and low HES1 and HEY1 levels, when taken in the context of the Notch repressor function for PTOV1 described above in cellular models, they are consistent with the notion that high levels of PTOV1 repress the transcriptional activity of Notch in metastatic prostate cancer.