Pleural CEA (≥6.0 ng/mL) can rule out MM with a high degree of certainty, and the positive results for combination of pleural CEA <6.0 ng/mL and HA >30,000 ng/mL can confirm MM with high specificity, prior to cytological or pathological examinations. The gene discussed is CEACAM5; the disease is Miyoshi myopathy.