Figure 4.
Identification and validation of the colon cancer risk subgroups based on the combined analysis of IDO1 and CD8A expression. (A) Scatter plot showing the expression between IDO1 and CD8A in colon cancer from The Cancer Genome Atlas (TCGA). Colon cancer patients were stratified into four groups based on bimodal value of IDO1 and the median expression value of CD8A. The groups divided by the first IDO1 peak (using solid blue lines) were named Group I, II, III, and IV. The groups were named Group I, II, III*, IV* when separated according to the secondary IDO1 peak (the higher cut-off for IDO1 expression, using solid red lines). Survival curves of OS (B, C) and DSS (D, E) across the colon cancer risk groups stratified by different IDO1 peaks were compared by Kaplan–Meier analysis for the TCGA cohort. (F) Scatter plot showing the expression between IDO1 and CD8A in colon cancer from the GSE17538 data set. The validation cohort (GSE17538) was conducted using the same approach to identify group III* and group IV* using the secondary IDO1 peak (the higher cut-off for IDO1expression). Kaplan–Meier survival plots for OS (G) and DFS (H) stratified according to the combined the secondary IDO1 peak and the median expression value of CD8A in the GSE17538 data set. The log-rank test P values are shown for each plot. OS, overall survival; DSS, disease specific survival; DFS, disease free survival.