We recently reported that the ratio of pleural lactate dehydrogenase to adenosine deaminase along with carcinoembryonic antigen (CEA) levels may be a valuable diagnostic marker for discriminating possible etiologies.[1,2] The accuracy of cytological examination to diagnose malignant pleural effusion ranges from 40% to 87%.[3–5] Furthermore, MM is one of the most challenging malignancies to diagnose. The gene discussed is CEACAM5; the disease is Miyoshi myopathy.