The goal of this observational study is to use endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) to investigate the intratumoral microbiome profile in patients with pancreatic ductal adenocarcinoma (PDAC) and to evaluate its potential impact on tumor diagnosis and prognosis. PDAC is the most common and lethal type of pancreatic cancer, accounting for over 85% of all pancreatic cancer cases. Given that most patients are diagnosed at an advanced stage when surgery is no longer an option, EUS-FNB serves as a crucial and minimally invasive method for accessing and analyzing the microbiome within the tumor.

The main questions this study aims to answer are:

Can EUS-FNB reliably and accurately detect the microbiome within PDAC tumors?

Researchers will analyze tissue samples obtained through EUS-FNB to confirm its ability to accurately capture the diversity and composition of the tumor microbiome.

Are there specific microbes or metabolites within the PDAC tumor microbiome that are linked to patient prognosis or response to chemotherapy?

The study will screen for and identify key microbial species or metabolites associated with treatment outcomes and patient survival in PDAC.

To ensure the reliability of the EUS-FNB results, researchers will systematically compare microbiome data obtained from EUS-FNB samples with those from surgical biopsies of pancreatic cancer tissue. This comparison will help validate the consistency and accuracy of the two methods in identifying the microbiome diversity and composition, confirming the clinical and research utility of EUS-FNB.

Participant Requirements:

Participants will be patients diagnosed with PDAC who require EUS-FNB as part of their clinical assessment and treatment pathway.

During the EUS-FNB procedure, researchers will use the remaining tissue after rapid on-site evaluation (ROSE) to conduct microbiome sequencing, ensuring sample quality.

All participants will provide informed consent, allowing the use of leftover tissue for microbiome analysis, and their privacy will be strictly protected throughout the study.

Study Procedures:

Participants will undergo a standard EUS-FNB procedure as part of their routine clinical care, with no additional procedures required for the study.

Researchers will compare the microbiome characteristics from EUS-FNB samples with those from surgical biopsy samples to verify consistency.

The study will utilize 2bRAD-M metagenomic sequencing technology, which is cost-effective and suitable for low-biomass, host-contaminated, and degraded microbiome samples. This method generates an accurate species-level taxonomic profile for analysis.

By identifying key microbial components or metabolites linked to patient prognosis or treatment response, this study aims to provide scientific evidence for early detection strategies and effective treatment plans for PDAC patients, potentially bringing significant clinical benefits.

Inclusion Criteria:

1. Males or females aged between 18 and 80 years.
2. Patients with pancreatic lesions confirmed through imaging examinations (US, MRI, CT, or PET-CT) with a high suspicion of pancreatic ductal adenocarcinoma (PDAC) who require EUS-FNB for diagnostic assistance.
3. Patients who have not received any chemotherapy, including neoadjuvant, postoperative adjuvant, or palliative chemotherapy.
4. Patients who agree to participate in this study and sign an informed consent form.

Exclusion Criteria:

1. Poor physical condition, including but not limited to hemoglobin ≤ 8.0 g/dl, severe cardiopulmonary insufficiency, etc.
2. Coagulation disorders (platelet count < 50 × 10^9/L, international normalized ratio > 1.5).
3. Failed anesthesia evaluation.
4. Acute pancreatitis within the past 2 weeks.
5. Pregnant or breastfeeding individuals.
6. Mental illness, drug addiction, or other conditions that may affect follow-up.
7. Patients who have received antibiotic treatment before the biopsy procedure or other conditions deemed unsuitable by the investigators.

At the Third Xiangya Hospital of Central South University, patients with pancreatic diseases requiring diagnosis through EUS-FNB.

There is not plan to make IPD avaliable