Given that CD20 is expressed on more mature B-cells, evaluation of the antigen with other markers (such as CD10 and CD38) define normal patterns of B-cell maturation, particularly important for evaluation of B-cell lymphoma in the bone marrow by flow cytometry, where normal B lymphoblasts could be mistaken for B-cell lymphoma. The gene discussed is MS4A1; the disease is B-cell non-Hodgkin lymphoma.