Human papillomavirus appears to play an etiologic role in many cancers of the oropharynx and possibly a small subgroup of cancers of the oral cavity, according to an article published in the Dec. 3 issue of Journal of the National Cancer Institute.
HPV is the causal agent of cervical cancer, and it appears to be involved in the etiology of oral and oropharyngeal cancers. Researchers conducted a multi-center case-control study of oral and oropharyngeal cancers in nine countries to investigate the associations.
The study included 1,670 case patients (1,415 with oral cancer and 255 with oropharyngeal cancer) and 1,732 cancer-free control subjects. They interviewed the subjects and obtained oral exfoliated cells and blood from all participants, as well as fresh biopsy specimens from case patients. They used polymerase chain reaction to detect HPV DNA and enzyme-linked immunosorbent assays to find antibodies against HPV16 L1, E6 and E7 proteins in plasma.
Researchers found HPV DNA in the biopsy specimens of 3.9 percent of subjects with oral cancer and 18.3 percent of subjects with oropharyngeal cancer. They detected HPV DNA in biopsy specimens from case subjects less frequently among tobacco smokers and betel-leaf chewers and more frequently among subjects who reported having had more than one sexual partner or who practiced oral sex. They also found DNA for HPV16, the most common type of HPV in genital tumors, in 94.7 percent of case subjects.
HPV DNA found in exfoliated cells was not associated with risk of developing cancer or with HPV DNA detection in biopsy specimens. The presence of antibodies against HPV16 L1, HPV16 E6 or E7, however, was associated with the risk of experiencing cancers of the oral cavity and the oropharynx.
The mechanism of transmission of HPV to the oral cavity warrants further investigation say researchers.
