title: Differential expression of BCL-2 family proteins in ALK-positive and ALK-negative anaplastic large cell lymphoma of T/null-cell lineage.
abstract: Anaplastic large-cell lymphoma (ALCL) of T- or null-cell lineage, as defined in the revised European-American lymphoma classification, includes a subset of tumors that carry the t(2;5)(p23;q35) resulting in overexpression of anaplastic lymphoma kinase (ALK). Patients with ALK+ ALCL are reported to have a better prognosis than patients with ALK- ALCL. Because the mechanisms for this survival difference are unknown, we investigated the hypothesis that apoptotic pathways may be involved. We therefore assessed expression levels of the anti-apoptotic proteins BCL-2 and BCL-XL and the pro-apoptotic proteins BAX and BCL-XS in T/null-cell ALCL using immunohistochemical methods and correlated the findings with ALK expression and apoptotic rate (AR), the latter assessed by a modified Tdt-mediated dUTP nick-end labeling assay. ALK was detected in 21 of 66 (31.8%) ALCLs. BCL-2 was not detected in 21 ALK+ ALCLs but was present in 26 of 45 (57.8%) ALK- ALCLs (P < 0.0001). ALK+ and ALK- ALCLs also showed significant differences in expression of BCL-XL, BAX, and BCL-XS. ALK+ tumors less commonly had a high level of BCL-XL (1 of 17 versus 14 of 35, P = 0.01), and more commonly had high levels of BAX (13 of 18 versus 15 of 36, P = 0.05), and BCL-XS (11 of 16 versus 12 of 31, P = 0.05) compared with ALK- tumors. ALK+ tumors also had a higher mean AR than ALK- tumors (3.4% versus 1.1%, P = 0.0002). Differential expression of BCL-2 family proteins may be responsible for the higher AR observed in ALK+ ALCL and provides a possible biological explanation for the better prognosis reported for patients with ALK+ ALCL.
authors.affiliation: Department of Lymphoma-Myeloma, University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX 77030, USA.
authors.forename: G Z
authors.initials: GZ
authors.lastname: Rassidakis
authors.forename: A H
authors.initials: AH
authors.lastname: Sarris
authors.forename: M
authors.initials: M
authors.lastname: Herling
authors.forename: R J
authors.initials: RJ
authors.lastname: Ford
authors.forename: F
authors.initials: F
authors.lastname: Cabanillas
authors.forename: T J
authors.initials: TJ
authors.lastname: McDonnell
authors.forename: L J
authors.initials: LJ
authors.lastname: Medeiros
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000077548:Anaplastic Lymphoma Kinase; D017209:Apoptosis; D002455:Cell Division; D002648:Child; D002675:Child, Preschool; D002874:Chromosome Mapping; D002889:Chromosomes, Human, Pair 2; D002895:Chromosomes, Human, Pair 5; D005260:Female; D019254:Genes, bcl-2; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008940:Mitotic Index; D009367:Neoplasm Staging; D011379:Prognosis; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases; D014178:Translocation, Genetic; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
chemical_list: C494826:BAX protein, human; C494811:BCL2L1 protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D011505:Protein-Tyrosine Kinases; D020794:Receptor Protein-Tyrosine Kinases