Elevated tumor markers in a benign lung disease

This study aimed to determine the underlying pathophysiologic mechanism of elevated carbohydrate antigen 19-9 (CA19-9) in pulmonary sequestration (PS) patients.

Four pulmonary sequestration patients, 12 pneumonia patients and 12 healthy adult volunteers were prospectively studied. Specimens from another 34 pulmonary sequestration patients were retrospectively analyzed. Serum CA19-9 levels of 4 patients were tested before and 1 week, 1 month and 3 months after surgery. The CA19-9 levels of 12 pneumonia patients and 12 healthy adult volunteers were tested as controls. The expression and localization of CA19-9 in diseased lesions and corresponding normal lung tissues were analyzed by Immunohistochemical (IHC). Hematoxylin-eosin (HE) staining was performed to observe the pathological changes in pulmonary sequestration tissues.

Serum CA19-9 levels were significantly higher in the 4 patients (797.3 ± 316 IU/ml) than in the pneumonia patients (10.07 ± 5.01 IU/ml) and healthy volunteers (9.85 ± 4.12 IU/ml). In addition, serum CA19-9 levels decreased dramatically after the focus was removed. Positive staining of CA19-9 was found in 70% (24/34) of pulmonary sequestration tissues, and CA19-9 was mainly expressed in the bronchial mucus. In the 4 diseased lesions, deformed alveolar structure and inflammatory cell infiltration were observed, and the degree of damage was positively correlated with serum CA19-9 levels.

CA19-9 could be generated by abnormal columnar epithelia in pulmonary sequestration tissues and was transported into circulation after alveoli damage. CA19-9 could serve as an adjuvant diagnostic marker in pulmonary sequestration.