title: Analysis of apoptosis protein expression in early-stage colorectal cancer suggests opportunities for new prognostic biomarkers.
abstract: OBJECTIVE
  Although most stage II colon cancers are potentially curable by surgery alone, approximately 20% of patients relapse, suggesting a need for establishing prognostic markers that can identify patients who may benefit from adjuvant chemotherapy. We tested the hypothesis that differences in expression of apoptosis-regulating proteins account for differences in clinical outcome among patients with early-stage colorectal cancer.
  
  
  METHODS
  Tissue microarray technology was employed to assay the expression of apoptosis-regulating proteins by immunohistochemistry in 106 archival stage II colorectal cancers, making correlations with disease-specific survival. The influence of microsatellite instability (MSI), tumor location (left versus right side), patient age, and gender was also examined.
  
  
  RESULTS
  Elevated expression of several apoptosis regulators significantly correlated with either shorter (cIAP2; TUCAN) or longer (Apaf1; Bcl-2) overall survival in univariate and multivariate analyses. These biomarkers retained prognostic significance when adjusting for MSI, tumor location, patient age, and gender. Moreover, certain combinations of apoptosis biomarkers were highly predictive of death risk from cancer. For example, 97% of patients with favorable tumor phenotype of cIAP2(low) plus TUCAN(low) were alive at 5 years compared with 60% of other patients (P = 0.00003). In contrast, only 37% of patients with adverse biomarkers (Apaf1(low) plus TUCAN(high)) survived compared with 83% of others at 5 years after diagnosis (P< 0.0001).
  
  
  CONCLUSIONS
  Immunohistochemical assays directed at detection of certain combinations of apoptosis proteins may provide prognostic information for patients with early-stage colorectal cancer, and therefore could help to identify patients who might benefit from adjuvant chemotherapy or who should be spared it.
authors.affiliation: The Burnham Institute, Department of Family Preventive Medicine, University of California-San Diego, La Jolla, California, USA.
authors.forename: Maryla
authors.initials: M
authors.lastname: Krajewska
authors.forename: Hoguen
authors.initials: H
authors.lastname: Kim
authors.forename: Chul
authors.initials: C
authors.lastname: Kim
authors.forename: Haeyoun
authors.initials: H
authors.lastname: Kang
authors.forename: Kate
authors.initials: K
authors.lastname: Welsh
authors.forename: Shu-Ichi
authors.initials: S
authors.lastname: Matsuzawa
authors.forename: Michelle
authors.initials: M
authors.lastname: Tsukamoto
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Thomas
authors.forename: Nuria
authors.initials: N
authors.lastname: Assa-Munt
authors.forename: Zhe
authors.initials: Z
authors.lastname: Piao
authors.forename: Koichi
authors.initials: K
authors.lastname: Suzuki
authors.forename: Manuel
authors.initials: M
authors.lastname: Perucho
authors.forename: Stan
authors.initials: S
authors.lastname: Krajewski
authors.forename: John C
authors.initials: JC
authors.lastname: Reed
mesh_terms: D000367:Age Factors; D017209:Apoptosis; D053477:Apoptotic Protease-Activating Factor 1; D015415:Biomarkers / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism*; D017024:Chemotherapy, Adjuvant; D003110:Colonic Neoplasms / Q000473:pathology; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D018895:Microsatellite Repeats; D015999:Multivariate Analysis; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D011379:Prognosis; D016016:Proportional Hazards Models; D011506:Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012189:Retrospective Studies; D012737:Sex Factors; D013997:Time Factors; D014018:Tissue Distribution; D016896:Treatment Outcome
chemical_list: C506592:APAF1 protein, human; D053477:Apoptotic Protease-Activating Factor 1; D015415:Biomarkers; D014408:Biomarkers, Tumor; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2