HTRA1 and pleural mesothelioma: The correlation of HtrA1 with histological differentiation was inconsistent, since it was demonstrated in esophageal (44) and endometrial (46,48) cancer and hepatocellular carcinoma (10), but not in breast (11), esophageal (45), and ovarian (50) cancer, whereas it was not assessed in NB (42), bladder (43), gastric (12), and endometrial cancer (47), pleural mesothelioma (9) and malignant melanoma (8).