PDCD6 and gastric cancer: Immune- and stress-related proteins included Protein S100-A8, a metastasis-associated protein [19]; T cell receptor alpha joining 56; Mal T-cell differentiation protein 2, which is associated with cancer aggressiveness [20]; programmed cell death protein 6, which has been reported as a prognostic marker for gastric cancers [21]; and peroxiredoxin-1, which is linked to the control of PCa growth [22].