Expression of BCL-2 proto-oncogene in adult acute lymphoblastic leukemia.
The products of the BCL-2 gene prolong survival of lymphohematopoietic cells by inhibition of programmed cell death. We studied bcl-2 protein expression in a series of 43 adult acute lymphoblastic leukemia (ALL) at diagnosis, using a specific monoclonal antibody and flow cytometry. All samples expressed bcl-2 with a mean percentage of positive cells of 77.9. The level of bcl-2 in positive cells expressed as mean equivalent of soluble fluorescence (MESF) was highly variable ranging from 5 x 10(3) to 552 x 10(3) (mean +/- s.d.: 96.5 +/- 109 x 10(3)). Neither the percentage of positive cells nor bcl-2 MESF levels were correlated with initial characteristics including blood counts, immunological phenotype, or cytogenetics. The survival of leukemic cells maintained in cytokine-free liquid culture was not correlated with bcl-2 expression. However, cells from ALL with higher white blood cell (WBC) counts, with t(9;22) translocation, or expressing myeloid surface antigens exhibited significantly longer survival in this culture system. The outcome after intensive chemotherapy did not differ according to bcl-2 expression. Factors associated with poor outcome included WBC counts, presence of t(9;22) translocation, presence of myeloid antigens and prolonged survival of cultured cells. These results indicate that high levels of bcl-2 are not associated with distinct clinical or biological characteristics in ALL.
Campos
L
L
Département d'Hématologie, CHRU de St Etienne, France.
Sabido
O
O
Sebban
C
C
Charrin
C
C
Bertheas
M F
MF
Fière
D
D
Guyotat
D
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D017209:Apoptosis; D002470:Cell Survival; D002892:Chromosomes, Human, Pair 22; D002899:Chromosomes, Human, Pair 9; D005434:Flow Cytometry; D015870:Gene Expression; D006801:Humans; D007958:Leukocyte Count; D016014:Linear Models; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D011379:Prognosis; D016016:Proportional Hazards Models; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D019253:Proto-Oncogene Proteins c-bcl-2; D011519:Proto-Oncogenes / Q000235:genetics*; D014178:Translocation, Genetic; D014407:Tumor Cells, Cultured / Q000473:pathology
D015214:Antigens, Differentiation, Myelomonocytic; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2