title: Change of CD20 Expression in Diffuse Large B-Cell Lymphoma Treated with Rituximab, an Anti-CD20 Monoclonal Antibody: A Study of the Osaka Lymphoma Study Group.
abstract: Change of CD20 expression was examined in cases of diffuse large B-cell lymphoma (DLBCL). CD20 expression after treatment with anti-CD20 antibody (rituximab, Rx) for DLBCL was examined in 23 cases who received serial biopsy by immunohistochemistry (IHC) and flow cytometry (FCM). CD20- by IHC and/or FCM was defined as CD20-. Four cases were CD20- at initial biopsy but became CD20+ after chemotherapy with Rx (CH-R) (group A). Recurrent tumors in three group A cases became resistant to CH-R. Initial and recurrent tumors were CD20+ before and after CH-R in 17 cases (group B). Tumors before CH-R were CD20- in two cases (group C) and continued to be CD20- in one and turned CD20+ in the other with survival time after the relapse of 8 and 23 months, respectively. Evaluation of CD20 expression with immunohistochemical and flow cytometric methods is used for the prediction of responsiveness of relapsed DLBCL for CH-R.
authors.affiliation: Department of Pathology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Wada
authors.forename: Masaharu
authors.initials: M
authors.lastname: Kohara
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Ogawa
authors.forename: Haruo
authors.initials: H
authors.lastname: Sugiyama
authors.forename: Shirou
authors.initials: S
authors.lastname: Fukuhara
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Tatsumi
authors.forename: Akihisa
authors.initials: A
authors.lastname: Kanamaru
authors.forename: Masayuki
authors.initials: M
authors.lastname: Hino
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kanakura
authors.forename: Eiichi
authors.initials: E
authors.lastname: Morii
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Aozasa