PDCD1 and type 2 diabetes mellitus: Fan et al. identified eight significant genes that were immunologically related cross-talk genes related to OC and T2DM: C1QC (Complement C1q subcomponent, C chain), NOS2 (Nitric Oxide Synthase 2), ABCD1 (ATP-Binding Cassette Sub-Family D Member 1), PD1A4 (PD-1 (Programmed Cell Death Protein 1) Auxiliary Protein 4), ALOX15 (Arachidonate Lipoxygenase 15), CSE1L (Chromosome Segregation 1-Like), IL1RN (Interleukin 1 Receptor Antagonist), and PSMC4 (Proteasome 26S Subunit ATPase 4) [163].