The relevant genes that were involved in the PI3K/AKT pathway activation observed in the T2DM-related periodontitis included those that affect apoptosis (e.g., FOXO1, BCL2, and growth differentiation factor 15 [GDF15]) and cell cycle passage (e.g., CDKN1B and CCND1). The gene discussed is CCND1; the disease is type 2 diabetes mellitus.