CYP27B1 and Hypercalcemia: Importantly, 25(OH)D elevation alone does not cause hypercalcemia; rather, in the context of CYP27B1 overexpression, it suggests enhanced production of active 1,25(OH)2D. Moreover, inflammatory cytokines within the lymphoma microenvironment can further upregulate CYP27B1 expression in macrophages, amplifying 1,25(OH)2D3 production [17].