BACKGROUNDTo study the effect of human papillomavirus (HPV) 16 E6/E7 and TPA (12-O-tetradecanog-1-phorbol-13-acetate) on malignant transformation of human embryo oral tissue.

METHODSRecombinant plasmid with HPV 16 E6/E7 was constructed and transfected into human embryo oral tissue. The oral tissue with HPV 16 E6/E7 gene or without the gene was inoculated into the hypophloeodal of right shoulder in scid mice, respectively. The study was conducted in four groups: the first group was the oral tissue transfected plasmid with HPV 16 E6/E7 plus TPA, which were inoculated into 8 scid mice; the second group was only oral tissue transfected with plasmid with HPV 16 E6/E7 into 6 scid mice; the third group was normal oral tissue plus TPA inoculated into 6 scid mice, and the final group was only normal oral tissue inoculated into 5 scid mice. Three days after inoculation, TPA was injected at the left shoulder of the mice once a week. Twelve weeks after inoculation, tumor was found in 7 scid mice from the first group. HPV 16 E6/E7 gene in tumor tissues was analyzed by PCR.

RESULTSThe rate of tumor formation was 7/8 in the first group; no tumor was found in the other groups. Pathological diagnosis of the tumor was fibrohistiocytoma. HPV 16 E6/E7 gene was detected by PCR in tumor tissues.

CONCLUSIONWith the cooperating action of TPA, human oral tissue containing HPV 16 E6/E7 gene could cause malignant transformation in scid mice.