Table 1.
Clinical and histopathological characteristics of patients.
Table 2.
List of selected gene expression assays.
Fig 1.
Hypoxia-related gene expression profiles according to clinicopathological data.
Gene expression was determined using quantitative real-time PCR as described in the Materials and Methods. The results are presented as the fold induction of relative quantification by classification in ascending order. A positive fold change of 1 indicated 2-fold up-regulation, and a negative fold change of -1 indicated 2-fold down-regulation. A comparative analysis was performed between (A) high tumor stage vs low tumor stage, (B) high mSBR grades vs low mSBR grades, (C) HER2+ status vs HER2- status, and (D) recurrent patients vs non-recurrent patients. Statistical analysis was performed between groups using Student’s t or Kruskal Wallis tests (red bar: p < 0.05; black bars: p < 0.10).
Fig 2.
Profile of hypoxia-related gene expression in 32 tumors from patients with early-stage breast cancer.
Data are presented in heat map format combined with hierarchical clustering using ΔCt values of gene expression. Each row represents a gene, and each column represents a patient. Gene expression is relative to the median of ΔCt values. Genes in red and green indicate expression above and below the median, respectively. (A) Hierarchical cluster analysis using all selected genes. (B) Hierarchical cluster analysis using the 6 differentially expressed genes with statistical significance between the recurrent group and non-recurrent group.
Fig 3.
Kaplan-Meier relapse-free survival curves according to the risk score of relapse.
Curve 1: 15 patients with score ≤ 2. Curve 2: 17 patients with score ≥ 3. The 14 recurrent patients were in curve 2 (p = 0.021, Mantel-Haenszel test).
Fig 4.
Analysis of the internal consistency of the 6 genes differentially expressed between recurrent and non-recurrent patients.
Cronbach’s alpha coefficient was calculated to measure internal consistency (alpha = 0.90).
Table 3.
Optimum level of gene expression thresholds discriminating relapse-free survival.