title: Proteomic analysis of apoptotic pathways reveals prognostic factors in follicular lymphoma.
abstract: Follicular lymphoma (FL) is the second most common non-Hodgkin's lymphoma and generally is incurable. Reliable prognostic markers to differentiate patients who progress rapidly from those who survive for years with indolent disease have not been established. Most cases overexpress Bcl-2, but the pathogenesis of FL remains incompletely understood. To determine whether a proteomic approach could help overcome these obstacles, we procured lymphoid follicles from 20 cases of FL and 15 cases of benign follicular hyperplasia (FH) using laser capture microdissection. Lysates were spotted on reverse-phase protein microarrays and probed with 21 antibodies to proteins in the intrinsic apoptotic pathway, including those specific for posttranslational modifications such as phosphorylation. A panel of three antibodies [phospho-Akt(Ser473), Bcl-2, and cleaved poly(ADP-ribose) polymerase] segregated most cases of FL from FH. Phospho-Akt(Ser473) and Bcl-2 were significantly increased in FL (P = 0.001 and P < 0.0001, respectively). Additionally, the Bcl-2/Bak ratio completely segregated FL from FH. High ratios of Bcl-2/Bak and Bcl-2/Bax were associated with early death from disease with differences in median survival times of 7.3 years (P = 0.0085) and 3.8 years (P = 0.018), respectively. Using protein microarrays, we identified candidate proteins that may signify clinically relevant molecular events in FL. This approach showed significant changes at the posttranslational level, including Akt phosphorylation, and suggested new prognostic markers, including the Bcl-2/Bak and Bcl-2/Bax ratios. Proteomic end points should be incorporated in larger, multicenter trials to validate the clinical utility of these protein microarray findings.
authors.affiliation: National Cancer Institute--Food and Drug Administration Clinical Proteomics Program, Laboratory of Pathology, Bethesda, MD 20892, USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Gulmann
authors.forename: Virginia
authors.initials: V
authors.lastname: Espina
authors.forename: Emanuel
authors.initials: E
authors.lastname: Petricoin
authors.forename: Dan L
authors.initials: DL
authors.lastname: Longo
authors.forename: Mariarita
authors.initials: M
authors.lastname: Santi
authors.forename: Turid
authors.initials: T
authors.lastname: Knutsen
authors.forename: Mark
authors.initials: M
authors.lastname: Raffeld
authors.forename: Elaine S
authors.initials: ES
authors.lastname: Jaffe
authors.forename: Lance A
authors.initials: LA
authors.lastname: Liotta
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Feldman
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006965:Hyperplasia; D007150:Immunohistochemistry; D008224:Lymphoma, Follicular / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D040081:Protein Array Analysis / Q000379:methods; D020543:Proteome / Q000032:analysis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D015398:Signal Transduction; D016019:Survival Analysis; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000032:analysis; D051028:bcl-2-Associated X Protein / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D020543:Proteome; D019253:Proto-Oncogene Proteins c-bcl-2; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein