PAX8 and peritoneal mesothelioma: Immunohistochemical studies have shown that PAX8 expression can help to distinguish ovarian cancer and pleural/ peritoneal mesotheliomas [35], with mesotheliomas demonstrating weak to negative staining of PAX8. A recent meta-analysis of 15 ovarian cancer studies, reported that prior exposure to asbestos is associated with an elevated risk of ovarian cancer [36] with ovarian cancers capable of metastasising to the pleura [37].