Open AccessComparison of CD 20 expression in B ‐cell lymphoma between newly diagnosed, untreated cases and those after rituximab treatment
Author(s) -
Miyoshi Hiroaki,
Arakawa Fumiko,
Sato Kensaku,
Kimura Yoshizo,
Kiyasu Junichi,
Takeuchi Masanori,
Yoshida Maki,
Ichikawa Ayako,
Ishibashi Yukinao,
Nakamura Yukihiko,
Nakashima Shinji,
Niino Daisuke,
Sugita Yasuo,
Ohshima Koichi
Publication year - 2012
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2012.02307.x
Subject(s) - rituximab , cd20 , lymphoma , medicine , biopsy , diffuse large b cell lymphoma , follicular lymphoma , b cell lymphoma , b cell , gastroenterology , pathology , immunology , antibody
Few studies have statistically investigated reduced CD 20 expression in B‐cell lymphoma after rituximab therapy and genomic mutation of CD 20 associated with reduction. We examined CD 20‐positive rate in follicular lymphoma ( FL ) and diffuse large B‐cell lymphoma ( DLBCL ) by flow cytometry ( FCM ) and immunohistochemical staining ( IHS ), comparing 138 cases after rituximab therapy with 360 initial, not yet treated cases. Sequence analysis of exons 3 to 8 of CD 20 was performed on 22 cases with low CD 20‐positive rate after rituximab treatment. The results showed a statistical correlation between CD 20‐positive rate in FCM and IHS . By FCM , the CD 20‐positive rate among post‐rituximab cases was significantly lower than among initial cases in DLBCL , non‐germinal center origin B‐cell type (average values [avg] 57.8 and 87.9, respectively) ( P < 0.0001), FL 2 (avg, 93.9; 103.2) ( P = 0.0083), and FL 3A (avg, 90.6; 100.7) ( P = 0.033). Stratified analyses of post‐rituximab cases showed significantly lower CD 20‐positive rate in cases that were resistant at the start of the treatment and cases with progressive disease during rituximab therapy before biopsy. Sequence analysis showed silent mutation of exon 4 (632 C/T) in seven cases, although this number was not statistically significant. These results suggest the influence of B‐lymphoma subtype and a therapeutic effect before biopsy on CD 20 expression at relapse and contribute to a better therapeutic approach for relapse cases after rituximab therapy. ( Cancer Sci , doi: 10.1111/j.1349‐7006.2012.02307.x, 2012)