Moreover, CpGs located at the CD274/PD-L1 promoter region and CD279/PD-1 were also included in the panel design, since they have recently emerged as an independent prognostic factor associated with shorter overall survival in triple negative breast, colorectal, prostate, gastric, papillary thyroid, melanoma and head and neck cancer patients (16–27). This evidence concerns the gene PDCD1 and head and neck cancer.