This is an exploratory, single-center, being conducted at Beijing Haidian Hospital in order to detect the relationship between microbiome of upper gastrointestinal and pathogenesis of multiple primary lung cancer.

This study intends to analyze the bacterial community structure of respiratory tract, upper digestive tract, lesion and adjacent to cancer in patients with multiple primary lung cancer, and to explore the association between upper digestive tract bacterial community and lung microecology, in order to find the characteristics of upper digestive tract bacterial strains involved in regulating lung cancer microenvironment, and explore the possible interaction mechanism between upper digestive tract bacterial community and lung cancer gene mutation.

Inclusion Criteria:

1. At least 18 years of age (including 18 years of age, male or female) and voluntarily signed informed consent;
2. Chest CT imaging showed at least 2 pulmonary nodules with a diameter of less than 3cm in ipsilateral lung, and imaging diagnosis of highly suspicious multiple primary lung cancer
3. No surgical contraindication, surgical resection is feasible, and postoperative pathology is diagnosed as multiple primary lung cancer according to Martini and Melamed criteria and gene testing
4. The amount of at least 2 or more tissues removed from multiple pulmonary nodules must meet the requirements of pathological diagnosis, molecular detection and microflora detection

Exclusion Criteria:

1. under 18 years of age (excluding 18 years of age, male or female) or unwilling to sign informed consent;
2. severe heart, liver, brain, kidney and other important organ diseases and bone marrow hematopoietic dysfunction;
3. Preoperative examination of patients who cannot tolerate surgical resection
4. Patients who received antibiotics within 1 week before surgery E) Resected multiple pulmonary nodules with pathologically proven lung cancer of less than 2 patients
5. Multiple nodules resected were confirmed to be metastases, not primary lung cancer

Multiple primary lung cancer patients