Comparison of survival outcome between subtype V patients with and without adjuvant chemotherapy. Comparisons of survival were conducted for patients in our dataset (upper panels) and the NKI dataset  (lower panels). The comparison of pertinent clinical parameters showed no differences between the two treatment groups from our KFSYSCC dataset (Table 5). Patients with subtype V breast cancer in the NKI database were identified using the classifier genes established in this study and centroid analysis. All NKI patients with N1 stage disease were selected for comparison. Tumor size distribution and the fraction of patients treated with hormonal therapy were not significantly different between the two treatment groups, with respective p values of 1.0 and 0.32 using Fisher's exact test. The NKI stage N0 patients were not included in this study because an overwhelming number did not receive adjuvant chemotherapy. Their inclusion would have caused an uneven distribution of disease severity. The results show that adjuvant chemotherapy did not provide survival benefit for patients with early stage subtype V breast cancer in either dataset.