Current state-of-the-art lung cancer early screening utilizes low-dose CT scan to identify lung nodules smaller than 3 cm in diameter. However, it's still a clinical challenge to differentiate between malignant and benign nodules.

In previous studies, the investigators had taken the approach of methylation profiling by high throughput bisulfite DNA sequencing in tissue samples to identify specific methylation signatures. The investigators had learned methylation patterns that differentiate malignant vs. benign lesions from tissue samples by in-depth data mining, and then used pattern matching to classify plasma samples.

In this study, the investigators are going to validate the efficacy of ctDNA methylation test for diagnosing early lung cancer by comparing results of the pre-surgery ctDNA methylation test with the post-surgery pathology.

This is a prospective, multi-center, observational cohort study and seeks to enroll 1230 participants with pulmonary nodules 5-30mm in diameter.

The assay analyzes the ctDNA methylation profiles of lung cancer-specific biomarkers non-invasively using whole blood specimens collected before invasive surgery.

The performance characteristics(sensitivity and specificity) of the pre-surgery ctDNA methylation test for detection of early lung cancer is evaluated in comparison to post-surgery pathology.

Inclusion Criteria:

• 18 years old or above
• single pulmonary nodule found by CT scan.
• the diameter of the pulmonary nodule is between 5mm to 30mm.
• plan to accept pneumonectomy due to the pulmonary nodule.
• without any sign of lymphatic or distant metastasis.
• agree to sign informed consent.

Exclusion Criteria:

• pregnant or lactating women.
• the diameter of the pulmonary nodule is more than 30mm
• there are 2 or more pulmonary nodules in one single patient.
• any sign of lymphatic or distant metastasis

Pre-surgery adult patients with single pulmonary nodule found by CT scan.