Optimizing ctDNA-based MRD Assessment in DLBCL, MCL, and FL Patients Undergoing CAR Therapy

This study is tracking how well a specialized blood test (called ctDNA, which detects cancer DNA in the blood) can predict treatment response in patients with certain B-cell lymphomas who are receiving CAR-T cell therapy. CAR-T therapy involves engineering a patient's own immune cells to attack cancer. The goal is to understand whether ctDNA testing can provide earlier and more accurate information than standard scans. **You may be eligible if...** - You have been diagnosed with follicular lymphoma, large B-cell lymphoma, or mantle cell lymphoma - You are scheduled to receive an FDA-approved CAR-T cell therapy for your lymphoma - You have measurable disease visible on a PET scan at the time of enrollment - A tissue sample from your diagnosis or relapse is available for genetic analysis **You may NOT be eligible if...** - No archival or fresh tissue sample is available to identify your cancer's genetic fingerprint for tracking Talk to your doctor to see if this trial is right for you.