CD56 Expression in Acute Lymphoblastic Leukemia of Childhood.
Margaret Ryan, Amy McGranahan, Xiayuan Liang. The Children's Hospital, Aurora, CO; University of Colorado Denver School of Medicine, Aurora
Background: CD56 antigen, a membrane glycoprotein, is a member of the immunoglobulin super-family. It is a crucial marker of natural killer (NK) cells and also expresses on a subset of mature T-cells and a subset cases of acute myeloid leukemia. The frequency and importance of this marker in association with acute lymphoblastic leukemia (ALL) in pediatric patients has not been closely studied and is greatly unknown. We examined CD56 expression in a large series of pediatric ALL cases in order to determine its significance in ALL, the most common neoplasm in childhood.
Design: 233 cases of newly diagnosed ALL (198 cases of B-ALL, 34 cases of T-ALL, and 1 case of true precursor NK cell leukemia) at The Children's Hospital, Colorado from 2003 to 2009 which had CD56 available were evaluated. Immunophenotype was performed by flow cytometry. Positive expression is defined as expression of a marker in ≥20% of blasts according to the criteria of the Children's Oncology Group.
Results: (1) CD56 expression was identified in 9 out of 233 cases (4%). Among these 9 cases, there were 5 cases of B-ALL (3%, 5/198), 3 cases of T-ALL (9%, 3/34), and 1 case of true precursor NK cell leukemia. (2) 3 cases of B-ALL with high CD56 expression (>50%) show co-expression of CD2. (3) 2 cases of T-ALL with high CD56 expression are double negative (CD4-CD8-) and both died within 1 year.
|Diagnosis||CD34/TdT (%)||CD2/CD7 (%)||CD3/cCD3 (%)||CD4/CD8 (%)||CD19/CD20 (%)||CD56 (%)||Outcome|
|B-ALL||97/97||95/1||NA/0||NA/NA||77/0||95||CR x 6 ys|
|B-ALL||99/48||41/0||1/1||2/0||98/1||70||CR x 1y|
|B-ALL||99/31||44/1||NA/NA||NA/NA||92/0||66||Died in 1y|
|B-ALL||93/30||2/3||NA/2||NA/NA||91/26||25||CR x 5 ys|
|B-ALL||80/78||0/1||NA/NA||NA/NA||87/0||22||CR x 5 ys|
|T-ALL||10/31||2/75||1/97||4/0||1/1||94||Died in <1y|
|T-ALL||100/4||95/100||99/99||2/18||0/0||54||Died in <1y|
|T-ALL||92/1||4/96||2/94||76/2||0/0||27||CR x 4 ys|
|True precursor NK-cell leukemia||0/0||96/26||3/5||2/3||0/0||96||CR x 7 ys|