EPCAM and malignant mesothelioma: In diagnostic surgical pathology, EpCAM immunohistochemistry (IHC) is employed for the distinction of malignant mesothelioma from primary lung cancer (summarized in [6]) and—due to its broad expression in epithelial neoplasms—as a surrogate pan-epithelial marker for the detection of circulating tumor cells (summarized in [7]).