Combining Napsin A expression with circulating tumor cell counts for enhanced identification of pulmonary adenocarcinoma in ground-glass nodules

Background: Circulating tumor cells (CTCs) have shown potential for early lung cancer diagnosis, but their sensitivity and isolation yield are currently limited. Napsin A is a sensitive and specific marker for adenocarcinoma diagnosis. Therefore, combining CTC detection with Napsin A expression analysis may provide an accurate method for identifying pulmonary adenocarcinoma in ground-glass nodules (GGNs), which could significantly improve patient survival rates. This study aims to evaluate the diagnostic value of detecting Napsin A‑positive CTCs for identifying pulmonary adenocarcinoma among patients with GGNs.

Methods: Peripheral blood samples were collected from 91 patients who had been diagnosed with GGNs. CTCs were captured using an efficient nano-enrichment method, and Napsin A expression was detected through immunofluorescent labeling. The diagnostic value of these metrics for pulmonary adenocarcinoma in GGNs was evaluated using receiver operating characteristic (ROC) curve analysis and the area under the curve (AUC).

Results: Our findings demonstrate that the number of CTCs in patients in the malignant group was significantly higher than that in the benign group (P<0.001). ROC analysis reveals an AUC of 0.627 for CTC detection alone, with a sensitivity of 63.64% and specificity of 72.46%. However, when CTC counts were combined with Napsin A-positive expression (Napsin A⁺), the diagnostic performance markedly improved: the sensitivity and specificity for detecting lung adenocarcinoma among GGNs rose to 90.91% and 88.41%, respectively, and the AUC increased to 0.918, indicating substantially enhanced discriminatory power.

Conclusions: The combination of CTC counting and Napsin A⁺ expression analysis holds promise for the identification of pulmonary adenocarcinoma in GGNs.