Expression of the adaptor protein BLNK/SLP-65 in childhood acute lymphoblastic leukemia.
Deficient expression of BLNK, an adaptor molecule crucial for normal B-cell development, is associated with increased pro-B/pre-B-cell expansion in mice. It has been proposed that BLNK deficiency is a primary cause of B-lineage acute lymphoblastic leukemia (ALL). We studied BLNK expression in the leukemic cells from 352 patients with childhood ALL (309 B-lineage; 43 T-lineage). By HG_U95Av2 Affymetrix GeneChip analysis, BLNK was expressed in 275 of 284 (96.8%) B-lineage ALL samples but in only one of 43 (2.3%) T-lineage ALL samples. Of 118 B-lineage ALL samples analyzed with the HG_U133A GeneChip, 117 (99.2%) expressed BLNK. All 30 primary B-lineage ALL samples studied by RT-PCR expressed BLNK transcripts; all 19 samples studied by Western blotting or flow cytometry expressed BLNK protein. Levels of BLNK in B-lineage ALL were as high as those of their normal counterparts; they were not related with genetic subgroups or differentiation stage. These results indicate that BLNK deficiency is a rare occurrence in childhood B-lineage ALL and is unlikely to be a common leukemogenic event as previously proposed.
Imai
C
C
Department of Hematology-Oncology, St Jude Children's Research Hospital, North Lauderdale, Memphis, TN 38105-2794, USA.
Ross
M E
ME
Reid
G
G
Coustan-Smith
E
E
Schultz
K R
KR
Pui
C H
CH
Downing
J R
JR
Campana
D
D
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins / Q000032:analysis* / Q000235:genetics; D019070:Cell Lineage; D006801:Humans; D010750:Phosphoproteins / Q000032:analysis* / Q000235:genetics; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis
D048868:Adaptor Proteins, Signal Transducing; C113939:B cell linker protein; D002352:Carrier Proteins; D010750:Phosphoproteins; D012333:RNA, Messenger