IDO1 and colonic neoplasm: To demonstrate the existence of the colon cancer risk subtypes, we applied the highest IDO1 peak (shown as a dotted blue line in Figure 4A) or the secondary IDO1 peak (the higher cut-off for IDO1expression, shown as a dotted red line in Figure 4A) to define the IDO1high and IDO1low populations, respectively, and then carried out stratification based on the median value of CD8A expression.