CD20 was first identified as a B-cell specific marker in 1980 [13], which was highly expressed on more than 80% of B-cell lymphomas but not on stem cells, pro-B cells, normal plasma cells, or other normal tissues [14].The CD20 gene, namely MS4A1 gene, is located on chromosome 11q12-q13.1 with 6 exons in its coding sequence (CDS) [15,16]. Here, MS4A1 is linked to B-cell non-Hodgkin lymphoma.