TSPAN8 and type 2 diabetes mellitus: The copy numbers of studies for risky genes in type-2 diabetes patients have shown that epidermal growth factor receptor (EGFR), E2F transcription factor 1 (E2F1), protein phosphatase 1 regulatory subunit 3A (PPP1R3A), human leukocyte antigen (HLA), and tetraspanin 8 (TSPAN8) are important.