**Study Summary:** This study looks at pancreatic adenocarcinoma, a very dangerous type of cancer that forms in the pancreas. The study wants to understand how the cancer's environment, called the tumor microenvironment, works, particularly focusing on two areas: **stromal cell prevalence** (types of cells around the tumor) and **metabolic reprogramming** (how cancer cells use energy differently). Researchers hope that by learning about these areas, they can find new ways to treat the cancer or predict how well treatments might work. **Key Points:** - **Participation Requirements:** You must be over 18, have social security, and be treated at Institut Paoli-Calmettes. You cannot have had chemotherapy before for the group you’re placed in. - **Study Procedures:** Participants will need a biopsy, a procedure to take a small piece of the tumor or metastasis, to help understand cancer better. - **Exclusions:** You cannot join if you're pregnant, have another active cancer, or cannot safely have a biopsy. This research could lead to better treatments for pancreatic cancer, but it's important to consider the requirements and procedures involved.