ESR1 and mantle cell lymphoma: In contrast, treating grafted DLBCL cells or other human B-cell lymphoma cells (mantle cell lymphoma and Burkitt lymphoma) with selective estrogen receptor agonists targeting the estrogen receptor β (ERβ/ESR2), the major nuclear estrogen receptor expressed in lymphoma cells [17], impaired tumor progression, reduced dissemination and vascularization, particularly lymphangiogenesis [18].