BioMed Central Acta Medica Okayama 1746-1596 8 2013 De novo CD5-positive diffuse large B-cell lymphomas show high specificity for cyclin D2 expression 81 EN Takuro Igawa Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yasuharu Sato Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Katsuyoshi Takata Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Noriko Iwaki Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Takehiro Tanaka Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Naoko Asano Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yoshinobu Maeda Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Yorihisa Orita Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Naoya Nakamura Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Shigeo Nakamura Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Tadashi Yoshino Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences 　D cyclins positively regulate the cell cycle and mediate the pathogenesis of some lymphomas. Cyclin D1 overexpression is the hallmark of mantle cell lymphoma, whereas cyclins D2 and D3 are reportedly not as specific to certain lymphomas as cyclin D1. In this study, cyclin D2 was found to be overexpressed in 98% of de novo CD5-positive diffuse large B-cell lymphomas (DLBCLs) (50/51) and in 28% of CD5-negative DLBCLs (14/51). A statistically significant difference was observed between these two groups (p<0.0001). In contrast, no statistical difference was found in the cyclin D3 expression between CD5-positive (18/51) and CD5-negative (24/51) DLBCLs (p=0.23). Based on these findings, cyclin D2 is therefore considered to be closely associated with de novo CD5-positive DLBCLs. This insight may be useful for overcoming the inferior survival of this aggressive lymphoma. No potential conflict of interest relevant to this article was reported.