Serum Antibody against Unfused Recombinant E7 Protein of Human Papillomavirus Type 16 in Cervical Cancer Patients

Sera were examined for the presence of antibody against E7 protein of human papillomavirus type 16 (HPV‐16) by Western blot analysis using the bacterially derived unfused protein. The occurrence rates of anti‐E7 antibody against HPV‐16 were 14.1% (10/71) in cervical cancer patients, 0% (0/48) in cervical intraepithelial neoplasia patients, and 0% (0/41) in female non‐malignant patients. Three patients (one with endometrial cancer, one with breast cancer, and one male patient with colon polyp) out of 115 patients with tumors in organs other than the cervix, had antibody against E7 protein of HPV‐16. The serum antibody, once positive, could be detected for a long time after surgical removal of the cancers in all cases that could be followed up. HPV‐16 DNA could be detected in 50% (13/26) of cervical cancer patients. Sixty‐nine percent (9/13) of patients with HPV‐16 DNA in cancers had the antibody and all the patients with stages II, III, and IV cervical cancer (8/8) harboring HPV‐16 DNA showed the presence of the antibody against E7 protein of HPV‐16. In contrast, only 20% (1/5) of cervical cancer patients with stage Ia or Ib harboring HPV‐16 DNA showed positive for the anti‐E7 antibody in sera. These findings suggest that the presence of anti‐E7 antibody in serum depends on the staging of cervical cancer and extent of HPV infection.