The researchers are aimed to investigate the early diagnosis of pulmonary nodule based on DNA, RNA, protein, metabolites through analyzing the serum, plasma, urine, faeces, peripheral blood mononuclear cell (PBMC), exhaled breath condensate and clinical characteristics.

By recruiting people with pulmonary nodules identified by CT scans, three groups are confirmed as the lung cancer group, the benign lung nodule group who are identified by pathological analysis, and the small lung nodule group that should be followed up. Then the serum, plasma, urine, faeces, peripheral blood mononuclear cell (PBMC), exhaled breath condensate and the clinical characteristics including age, sex, smoking status, BMI, address, greening environment and the laboratory tests are collected to analyze the ctDNA, RNA, protein, metabolites, immune status and their relationships with the tumorigenesis and the gene mutation of lung cancer.

Inclusion Criteria:

For lung cancer groups

• (1) Patients diagnosed with lung cancer;
• (2) Clear diagnosis by pathological examination to determine pathological type;
• (3) Those aged 18-80 years old;
• (4) For patients with newly diagnosed lung cancer, CT confirmed that the size of primary lung cancer is ≤ 3 cm;
• (5) The patient or family member agrees to participate in the study and sign an informed consent form;
• (6) No other serious cardiopulmonary diseases. For lung nodule
• (1) Those aged 18-80 years;
• (2) CT clear lung nodule size ≤ 3cm;
• (3) 1-3cm pulmonary nodules confirmed by pathological diagnosis as non-lung cancer or other metastatic cancer patients or ≤1cm pulmonary nodules
• (4) The patient or family member agrees to participate in the study and sign an informed consent form;
• (5) No other serious cardiopulmonary diseases.

Exclusion Criteria:

• (1) Women who are breast-feeding, pregnant or preparing for pregnancy;
• (2) Those who are allergic to allergies and multiple drugs;
• (3) Combining severe primary diseases such as cardiovascular and cerebrovascular, liver, kidney, and hematopoietic system, as well as subjects with mental illness;
• (4) concurrently infected;
• (5) Those who participated in other clinical trials within three months.

Subjects enrolled are volenteered and are willing to be followed up.