Retroperitoneal Lymphoma is related to hairy cell leukemia and reticulosarcoma. An important gene associated with Retroperitoneal Lymphoma is MME (Membrane Metalloendopeptidase), and among its related pathways/superpathways is Extrafollicular and follicular B cell activation by SARS-CoV-2. Affiliated tissues include pancreas and prostate, and related phenotype is immune system.