Furthermore, genetic and functional studies have demonstrated that BPIFA1 variants are associated with NPC susceptibility [90] and that loss of BPIFA1 expression correlates with poorer prognosis and reduced retinoic acid–induced growth inhibition and differentiation in NPC cells [91], suggesting that this protein family may play tumor-suppressive and mucosal-protective roles. The gene discussed is BPIFA1; the disease is nasopharyngeal carcinoma.