This study demonstrated that HSV is related to the severity of periodontal diseases in terms of clinical attachment loss. Coinfection of any two herpesviruses may also play roles.

In humans, fucosyltransferase-2 (FUT2) plays an important role in α1,2- linkage of fucose and participates in complex cellular processes such as fertilization, embryogenesis, and immune responses. However, little information is available concerning the FUT2 expression in tumorigenesis. The aim of this work was to investigate the combined effect of FUT2 gene polymorphisms and exposure to environmental carcinogens on the susceptibility and clinic pathological characteristics of oral cancer. Four SNPs of the FUT2 gene (rs281377, rs1047781, rs601338, and rs602662) from 1200 non-cancer controls and 700 oral squamous cell carcinoma (OSCC) patients were analyzed by real-time polymerase chain reaction (PCR). The samples were further analyzed to clarify the associations between these gene polymorphisms and the risk of OSCC, and the impact of these SNPs on the susceptibility and clinic pathological characteristics of OSCC. After adjusting for other covariant, we observed that betel quid chewing among 1255 smokers who carrying at least one C genotype (TC and CC) at rs281377 and least one T genotype (TA and TT) at rs1047781 were exhibited synergistic effects of environmental factors (betel quid and cigarette use) on the susceptibility of oral cancer. Taken together, our results support gene-environment interactions of FUT2 polymorphisms with smoking and betel quid chewing habits possibly altering oral cancer susceptibility. Furthermore, to our knowledge, this is the first study of association between FUT2 gene variants and OSCC risk.