title: Prognostic implications of cell cycle-related proteins in primary resectable pathologic N2 nonsmall cell lung cancer.
abstract: BACKGROUND
  Patients who have pathologic N2 (pN2) nonsmall cell lung cancer (pN2 NSCLC) represent a heterogeneous group with regard to prognosis and treatment. Molecular features of NSCLC seem to be of interest. For the current study, to select an appropriate therapeutic strategy for each patient, patients with N2 NSCLC were stratified into homogenous subgroups according to the expression profiles of cell cycle-related markers.
  
  
  METHODS
  The expression levels of retinoblastoma protein (pRb), cyclin D1, p16, p53, and p21 proteins and values of the Ki-67 labeling index were evaluated in 61 primary surgically resected tumor specimens from patients with pN2 NSCLC using immunohistochemistry. The prognostic impact of these markers on overall survival was analyzed in both univariate and multivariate analyses.
  
  
  RESULTS
  In univariate analysis, p21, p16, and Ki-67 were correlated significantly with survival. In multivariate analysis, only p21 and p16 influenced survival. Indeed, the group of patients with pN2 NSCLC who were positive for p21 and p16 had the most favorable overall survival (P = .001) and were correlated significantly with the clinical lymph node (cN) status (cN2 disease; P = .008). Moreover, no significant difference in survival was observed between patients with cN0/cN1 disease and patients with cN2 disease within the group (P = .4333).
  
  
  CONCLUSIONS
  Loss of control of cell-cycle checkpoints is a common occurrence in pN2 NSCLC. Functional cooperation between different cell-cycle regulators constitutes another level of regulation in cell growth control and tumor suppression. Preoperative patients with pN2 NSCLC, even those with cN2 disease, who have positive p21 and p16 protein expression in their primary tumors are expected to have a favorable postoperative prognosis and may be candidates for primary resection.
authors.affiliation: Department of Thoracic Surgery. Graduate School of Medicine. Chiba University, Chiba, Japan.
authors.forename: Sherif
authors.initials: S
authors.lastname: Mohamed
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yasufuku
authors.forename: Kenzo
authors.initials: K
authors.lastname: Hiroshima
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nakajima
authors.forename: Shigetoshi
authors.initials: S
authors.lastname: Yoshida
authors.forename: Makoto
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Sekine
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Shibuya
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Iizasa
authors.forename: Atef
authors.initials: A
authors.lastname: Farouk
authors.forename: Takehiko
authors.initials: T
authors.lastname: Fujisawa
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D014408:Biomarkers, Tumor / Q000378:metabolism; D018287:Carcinoma, Large Cell / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D018797:Cell Cycle Proteins / Q000378:metabolism*; D019938:Cyclin D1 / Q000378:metabolism; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D016160:Retinoblastoma Protein / Q000378:metabolism; D012189:Retrospective Studies; D015996:Survival Rate; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; D019938:Cyclin D1