In particular, recent data demonstrated that Porphyromonas gingivalis, one of the major pathogens involved in periodontal disease, induced platelets aggregation and the expression of several cell adhesion molecules, such as the intercellular adhesion molecule 1 (ICAM-1), the vascular cell adhesion molecule 1 (VCAM-1) and p-selectin. The gene discussed is VCAM1; the disease is periodontal disorder.