OBJECTIVE To study the effect of human papillomavirus (HPV) and tumour promoters spermidine (SPD and N-butyrate) on malignant transformation of human embryo cervical cells. METHODS Plasmid HPV16E6/E7 was constructed and transfected into human embryo cervical cells obtained by induced labor from pregnant women with severe heart diseases. Twenty-one scid mice were divided into 4 groups: experimental group (n = 7, incubated subcutaneously with the transfected cervical cells at the right shoulder, and then injected subcutaneously with spermidine and N-butyrate at the left shoulder three days after the incubation once a week for 12 times), virus-infected group B (n = 5, incubated subcutaneously with transfected cervical cell only), tumor promoter group (n = 5, incubated with untransfected cervical cells and SPD and N-butyrate), and control group (n = 4, incubated subcutaneously with only untransfected cervical cells). Twelve weeks after incubation, the mice were killed. Pathological reexamination was conducted to detect the existence of tumor. PCR was used to detect HPV16E6/E7 gene in tumor tissues. RESULTS Tumor, diagnosed as fibrosarcoma by pathology, was found in 5 out of the 7 mice in the experimental group. The tumor-forming rate was 0 in other groups. Expression of HPV16E6/E7 gene was detected in tumour tissues by PCR. CONCLUSIONS HPV16E6/E7 gene containing retrovirus infection, synergized by spermidine and N-butyrate acid, causes malignant transformation in human cervical cells.