In Europe diffuse large B-cell lymphoma (DLBCL) is a rare disease whereas in Italy it is not. Approximately 40% of DLBCL patients has refractory disease or will relapse after initial response. In onco-hematology, a role for gut microbiota (GM) in mediating immune activation in response to chemotherapy, has been suggested. In this scenario, the Investigators hypothesized that GM could play an important role in DLBCL prognosis and response to treatment, establishing a connection between lifestyle and clinical response. The project is aimed to the study of the functional GM layout in association with specific patterns of treatment response in de novo DLBCL undergoing standard first line chemo-immunotherapy. Results may build the scientific basis to design new and personalized intervention strategies (both in treatment approach and in life-style recommendations), to enhance clinical response and reduction of disease refractoriness through modulation of the gut microbial ecosystem.

Inclusion Criteria:

1. Age ≥18 years
2. Patients affected by histologically confirmed diffuse large B-cell lymphoma
3. Patients amenable for therapy with RCHOP (RCHOP is the standard first line therapy for DLBCL and it scheduled regardless of participation in present study).
4. Patients must provide written informed consent.

Exclusion Criteria:

1. Concomitant second malignancy, other than lymphoma.
2. Previous anti-lymphoma therapy.
3. Pregnancy or breastfeeding.
4. Evidence of significant, uncontrolled concomitant diseases that could affect compliance with the protocol or interpretation of results.

Patients affected by diffuse large B-cell lymphoma (DLBCL) undergoing therapy with front-line R-CHOP (rituximab-cyclophosphamide, doxorubicin, vincristine, prednisone).