NOS2 and type 2 diabetes mellitus: Another study by Fan and team identified eight crucial genes that were immunologically related cross-talk genes, which were C1QC (Complement C1q subcomponent, C chain), ABCD1 (ATP-Binding Cassette Sub-Family D Member 1), NOS2 (Nitric Oxide Synthase 2), PD1A4 (PD-1 (Programmed Cell Death Protein 1) Auxiliary Protein 4), IL1RN (Interleukin 1 Receptor Antagonist), ALOX15 (Arachidonate Lipoxygenase 15), CSE1L (Chromosome Segregation 1-Like) and PSMC4 (Proteasome 26S Subunit ATPase 4) related to OSCC (Oral Squamous Cell Carcinoma) and T2D (type 2 diabetes mellitus).