Fig. 3

Immunohistochemical staining. a CD20 immunohistochemical stain revealed diffuse infiltration of B cells (CD20 ×100). b BCL2-positive neoplastic cells surrounded reactive germinal centers containing proliferating B cells (BCL2 ×200) (c), which were highlighted by Ki-67 (Ki-67 ×100). d Immunohistochemical staining results for cyclin D1 protein were negative (cyclin D1 ×100)