PRSS23 has been reported to be overexpressed in malignant pleural mesothelioma [22], in breast cancer cells that are positive for the ligand-binding domain of estrogen receptor-α [8], and in gastric cancer patients [21,23]; however, in Ewing sarcoma, the expression was reduced [24]. This evidence concerns the gene ESR1 and malignant pleural mesothelioma.