CD20 gene deletion causes a CD20-negative relapse in diffuse large B-cell lymphoma.
In diffuse large B-cell lymphoma (DLBCL), a CD20-negative relapse is clinically significant because it is associated with chemo-refractory phenotypes and loss of a therapeutic target. The alteration of the CD20 gene is reported as infrequent in CD20-negative relapse in B-cell lymphoma. We established a DLBCL cell line with loss of CD20 expression (SD07) from a patient at CD20-negative relapse. She was initially diagnosed with CD20-positive DLBCL and received repeated immuno-chemotherapy that included rituximab. SD07, which has an immunoglobulin κ rearrangement identical to that of lymphoma cells at CD20-negative relapse, showed homozygous deletion of the CD20 gene with loss of the copy number of 11q12. SD07 is the first case in which it is proven that the loss of CD20 expression in relapsed DLBCL is the result of deletion of the CD20 gene. Deletion of the CD20 gene is a molecular mechanism of CD20-negative relapse in a subset of DLBCL.
Division of Hematology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan. nakamaki@med.showa-u.ac.jp
Tsuyoshi
T
Nakamaki
Kunihiko
K
Fukuchi
Hidetoshi
H
Nakashima
Hirotsugu
H
Ariizumi
Takashi
T
Maeda
Bungo
B
Saito
Kouji
K
Yanagisawa
Shigeru
S
Tomoyasu
Mayumi
M
Homma
Eisuke
E
Shiozawa
Toshiko
T
Yamochi-Onizuka
Hidekazu
H
Ota
D000368:Aged; D018951:Antigens, CD20 / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D006801:Humans; D007621:Karyotyping; D016133:Polymerase Chain Reaction
D018951:Antigens, CD20