CD27 and cancer: The further analysis of immune checkpoints in this study revealed that the expressions of protective factors such as TNFRSF4, CD27, TNFRSF25, PDCD1, TNFRSF14, CD40, and TIGIT were significantly lower in the high-risk group, while expressions of cancer promotors such as PDCD1LG2, TNFSF9, NRP1, CD276, and CD44 were significantly higher in this group, also suggesting that the high-risk group has poor overall survival [32–35].