We next evaluated the differences in N-ERC/mesothelin levels among each histologic type of pleural mesothelioma using the 7–20 ELISA system, because we have previously reported, using our former 7–16 ELISA system, that the epithelioid type shows higher levels of N-ERC/mesothelin in sera compared with other histologic types 20. The gene discussed is MSLN; the disease is pleural mesothelioma.