title: Prediction of recurrence-free survival in postoperative non-small cell lung cancer patients by using an integrated model of clinical information and gene expression.
abstract: OBJECTIVE
  One of the main challenges of lung cancer research is identifying patients at high risk for recurrence after surgical resection. Simple, accurate, and reproducible methods of evaluating individual risks of recurrence are needed.
  
  
  METHODS
  Based on a combined analysis of time-to-recurrence data, censoring information, and microarray data from a set of 138 patients, we selected statistically significant genes thought to be predictive of disease recurrence. The number of genes was further reduced by eliminating those whose expression levels were not reproducible by real-time quantitative PCR. Within these variables, a recurrence prediction model was constructed using Cox proportional hazard regression and validated via two independent cohorts (n = 56 and n = 59).
  
  
  RESULTS
  After performing a log-rank test of the microarray data and successively selecting genes based on real-time quantitative PCR analysis, the most significant 18 genes had P values of <0.05. After subsequent stepwise variable selection based on gene expression information and clinical variables, the recurrence prediction model consisted of six genes (CALB1, MMP7, SLC1A7, GSTA1, CCL19, and IFI44). Two pathologic variables, pStage and cellular differentiation, were developed. Validation by two independent cohorts confirmed that the proposed model is significantly accurate (P = 0.0314 and 0.0305, respectively). The predicted median recurrence-free survival times for each patient correlated well with the actual data.
  
  
  CONCLUSIONS
  We have developed an accurate, technically simple, and reproducible method for predicting individual recurrence risks. This model would potentially be useful in developing customized strategies for managing lung cancer.
authors.affiliation: Cancer Research Center, Center for Clinical Research, Samsung Biomedical Research Institute, Seoul, South Korea.
authors.forename: Eung-Sirk
authors.initials: ES
authors.lastname: Lee
authors.forename: Dae-Soon
authors.initials: DS
authors.lastname: Son
authors.forename: Sung-Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Jinseon
authors.initials: J
authors.lastname: Lee
authors.forename: Jisuk
authors.initials: J
authors.lastname: Jo
authors.forename: Joungho
authors.initials: J
authors.lastname: Han
authors.forename: Heesue
authors.initials: H
authors.lastname: Kim
authors.forename: Hyun Joo
authors.initials: HJ
authors.lastname: Lee
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Choi
authors.forename: Youngja
authors.initials: Y
authors.lastname: Jung
authors.forename: Miyeon
authors.initials: M
authors.lastname: Park
authors.forename: Yu Sung
authors.initials: YS
authors.lastname: Lim
authors.forename: Kwhanmien
authors.initials: K
authors.lastname: Kim
authors.forename: YoungMog
authors.initials: Y
authors.lastname: Shim
authors.forename: Byung Chul
authors.initials: BC
authors.lastname: Kim
authors.forename: Kyusang
authors.initials: K
authors.lastname: Lee
authors.forename: Nam
authors.initials: N
authors.lastname: Huh
authors.forename: Christopher
authors.initials: C
authors.lastname: Ko
authors.forename: Kyunghee
authors.initials: K
authors.lastname: Park
authors.forename: Jae Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Yong Soo
authors.initials: YS
authors.lastname: Choi
authors.forename: Jhingook
authors.initials: J
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000401:mortality* / Q000473:pathology*; D018572:Disease-Free Survival; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000235:genetics* / Q000401:mortality* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D020411:Oligonucleotide Array Sequence Analysis; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D020133:Reverse Transcriptase Polymerase Chain Reaction