Associations of serum anti-HPV 16 and 18 antibodies and prognostic parameters of cervical cancer are shown in Table 4. Patients with FIGO stage 1 cervical cancer had significantly higher HPV 16 seropositivity than those with FIGO stage 2 to 4 cervical cancer. Seropositivity to HPV 16 was also significantly higher in squamous cell carcinoma than those of other cell types. In the univariable analysis, prolonged disease-free survival was found to be significantly associated with seropositivity to HPV 16, advanced stage, tumor size, and lymph node status. However, according to the multivariable analysis, only advanced stage and lymph node status were significantly correlated with survival (Table 5). Kaplan-Meier survival estimates showed that seropositivity to HPV 16 was significantly associated with better disease-free survival (P=.017) (Fig. 2A) and seropositivity to HPV 18 showed a trend (P=.523, not significant) for better disease-free survival (Fig. 2B).
Among various research conducted on HPV infection, studies on serologic response have not delivered practical contribution to the clinicians. The reasons are an officially recognized serologic test remains unavailable because international standardization for HPV antigen has only been recently introduced and the fact that HPV infection does not often induce a systemic infection that leads to the production of antibodies detectable using serologic test. Such low immunity is the result of HPV infections restricted to the intraepithelial layer, absence of a bloodborne phase, lack of proinflammatory cytokine release, and antigen-presenting cells inactivation.17–19 As a result of the mentioned disadvantages, the serologic HPV assay has less been used compared with cervical HPV DNA detection, yet HPV DNA detection has its limitation in representing only the current infection because most of the HPV infection regresses and clears away naturally and current HPV infection does not always imply progression into cervical lesions. On the other hand, serum anti-HPV antibodies, which include cumulative HPV exposures and immune clearance, have the advantage of providing more comprehensive information on HPV infection.3,8–10
This study investigates the association of clinical aspects involved in the sequential step of cervical carcinogenesis with cervical HPV DNA and serum anti-HPV 16 and 18 antibodies, respectively. Foremost, we evaluated the relationship between HPV infection status and previously known demographic characteristics involved in cervical carcinogenesis. Similar to previous studies, HPV DNA positivity and HPV seropositivity were related to younger age, single marital status, a higher number of lifetime partners, an early sexual debut, and a history of STD,20,21 yet, on the contrary to past findings, the seropositivity decreased as the number of full-term deliveries increased in this study, and this can be explained by the recent changes in the Korean sexual culture wherein younger women are preferring liberalism and either nulliparity or single parity.9,22,23
In addition, although HPV DNA can only distinguish cervical neoplasia from normal cytology, serum anti-HPV 16 antibodies were capable of further distinguishing CIN 1 from CIN 2 and 3. Distinguishing CIN 1 from CIN 2 and 3 is important because, although CIN 1 pathologically undergoes viral replication with no cell proliferation and shows a high spontaneous regression, CIN 2 and 3 undergoes cell proliferation and thus clinically requires surgical intervention as a result of the risk of progression.3,10,24 The results of anti-HPV 16 antibodies in this study suggest the possibility of using serologic HPV assay as an adjuvant tool in identifying women at risk of developing a high-grade CIN.
According to our findings on invasive cervical cancer, HPV 16 seropositivity was associated with squamous cell carcinoma as expected because more than 70% of the squamous cell carcinoma worldwide is contributed by the HPV type 16.3,10,25 In addition, HPV 16 seropositivity was higher in FIGO stage 1 than in FIGO stage 2–4. Considering that the HPV 16 seropositivity was also high in CIN 2 and 3 compared with CIN 1 and together with the aforementioned result, HPV may be participating in the early stages of carcinogenesis.
Survival analysis revealed that seropositivity to HPV 16 was associated with prolonged disease-free survival in the univariable analysis, and this may suggest a potential association of anti-HPV antibodies with prognosis. Explanations on such possible association between HPV 16 seropositivity and prognosis have been suggested in several previous studies. Skiba et al reported that HPV 16 seropositivity was correlated with prolonged disease-free and overall survival, particularly in the patients with early FIGO stage 1 and 2 according to the univariable analysis. They state that seronegative patients exhibited a decrease in HPV-specific immune competence, allowing the virus to escape the immune system and consequently reducing the immunosuppression of HPV-induced tumor.26 Moreover, Heim et al previously reported that HPV capsid protein antibodies can indicate malignant lesions with persistent episomal HPV DNA and that these lesions with episomal forms are found to be associated with better disease-free survival than those with only integrated DNA. This is because malignant transformation accompanied by the expressions of oncoprotein is increased when episomal HPV DNA is integrated into the chromosomal DNA. Thus, remaining episomal HPV DNA in lesions implied that both the HPV DNA integration and malignant transformation are yet to be complete. Our findings together with previous studies suggest that cancer progresses more rapidly as a result of either the evasion of immunosurveillance or the decrease in the patient's immunocompetence in advanced stages.27
There are several limitations in this study. First is its cross-sectional nature representing a single time point during the disease process. Another is the hybrid capture II test that detects 13 high-risk types of HPV at a time and provides an overall status with a lack of HPV DNA type-specific information. The sensitivity of the hybrid capture II tests in detecting lesions of CIN 2 or more has been reported with a wide variation (66–100%) with the overall sensitivity of 90%.28,29 This could be the reason for the 87.3% HPV DNA positivity among cervical cancer in this study. Furthermore, there is limitation for the sample size of recurrence in this study causing low statistical power. The event rate was 12.9% in this study, and an event rate of 40% is needed to establish an adequate statistical power.30
In conclusion, among various demographic characteristics, sexual behavior factors were associated with higher tendency of cervical and serologic HPV positivity. Our results revealed that although HPV DNA is limited in distinguishing cervical neoplasia from normal control participants, serologic HPV assay using anti-HPV 16 antibodies is capable of distinguishing CIN 1 from CIN 2 and 3. Furthermore, our results show that serum anti-HPV 16 antibodies may also have the possibility of presenting a favorable prognostic value in cervical cancer.
1. Munoz N, Bosch FX, de Sanjose S, Herrero R, Castellsague X, Shah KV, et al.. Epidemiologic classification of human papillomavirus types associated with cervical cancer. N Engl J Med 2003;348:518–27.
2. Tota JE, Chevarie-Davis M, Richardson LA, Devries M, Franco EL. Epidemiology and burden of HPV infection and related diseases: implications for prevention strategies. Prev Med 2011;53:S12–21.
3. Snijders PJ, Steenbergen RD, Heideman DA, Meijer CJ. HPV-mediated cervical carcinogenesis: concepts and clinical implications. J Pathol 2006;208:152–64.
4. Castellsague X, Munoz N. Chapter 3: cofactors in human papillomavirus carcinogenesis–role of parity, oral contraceptives, and tobacco smoking. J Natl Cancer Inst Monogr 2003:20–8
5. Bosch FX, de Sanjose S. The epidemiology of human papillomavirus infection and cervical cancer. Dis Markers 2007;23:213–27.
6. Schiffman M, Wentzensen N, Wacholder S, Kinney W, Gage JC, Castle PE. Human papillomavirus testing in the prevention of cervical cancer. J Natl Cancer Inst 2011;103:368–83.
7. Naucler P, Ryd W, Tornberg S, Strand A, Wadell G, Elfgren K, et al.. Efficacy of HPV DNA testing with cytology triage and/or repeat HPV DNA testing in primary cervical cancer screening. J Natl Cancer Inst 2009;101:88–99.
8. Ho GY, Studentsov YY, Bierman R, Burk RD. Natural history of human papillomavirus type 16 virus-like particle antibodies in young women. Cancer Epidemiol Biomarkers Prev 2004;13:110–6.
9. Kim MA, Oh JK, Chay DB, Park DC, Kim SM, Kang ES, et al.. Prevalence and seroprevalence of high-risk human papillomavirus infection. Obstet Gynecol 2010;116:932–40.
10. Stanley M. Pathology and epidemiology of HPV infection in females. Gynecol Oncol 2010;117:S5–10.
11. Markowitz LE, Sternberg M, Dunne EF, McQuillan G, Unger ER. Seroprevalence of human papillomavirus types 6, 11, 16, and 18 in the United States: National Health and Nutrition Examination Survey 2003-2004. J Infect Dis 2009;200:1059–67.
12. Desai S, Chapman R, Jit M, Nichols T, Borrow R, Wilding M, et al.. Prevalence of human papillomavirus antibodies in males and females in England. Sex Transm Dis 2011;38:622–9.
13. Jeong NH, Lee NW, Woo MK, Kim HJ. Serologic response to human papillomavirus type 16 virus-like particles in Korean women with cervical precancerous and cancerous lesions. Arch Pharm Res 2009;32:383–9.
14. Frazer IH. Prevention of cervical cancer through papillomavirus vaccination. Nat Rev Immunol 2004;4:46–54.
15. Dias D, Van Doren J, Schlottmann S, Kelly S, Puchalski D, Ruiz W, et al.. Optimization and validation of a multiplexed Luminex assay to quantify antibodies to neutralizing epitopes on human papillomaviruses 6, 11, 16, and 18. Clin Diagn Lab Immunol 2005;12:959–69.
16. Woolson RF, Bean JA. Mantel-Haenszel statistics and direct standardization. Stat Med 1982;1:37–9.
17. Ferguson M, Wilkinson DE, Heath A, Matejtschuk P. The first international standard for antibodies to HPV 16. Vaccine 2011;29:6520–6.
18. Tindle RW. Immune evasion in human papillomavirus-associated cervical cancer. Nat Rev Cancer 2002;2:59–65.
19. Einstein MH, Schiller JT, Viscidi RP, Strickler HD, Coursaget P, Tan T, et al.. Clinician's guide to human papillomavirus immunology: knowns and unknowns. Lancet Infect Dis 2009;9:347–56.
20. Skjeldestad FE, Mehta V, Sings HL, Ovreness T, Turpin J, Su L, et al.. Seroprevalence and genital DNA prevalence of HPV types 6, 11, 16 and 18 in a cohort of young Norwegian women: study design and cohort characteristics. Acta Obstet Gynecol Scand 2008;87:81–8.
21. Roteli-Martins CM, de Carvalho NS, Naud P, Teixeira J, Borba P, Derchain S, et al.. Prevalence of human papillomavirus infection and associated risk factors in young women in Brazil, Canada, and the United States: a multicenter cross-sectional study. Int J Gynecol Pathol 2011;30:173–84.
22. Pereira CR, Rosa ML, Vasconcelos GA, Faria PC, Cavalcanti SM, Oliveira LH. Human papillomavirus prevalence and predictors for cervical cancer among high-risk women from Rio de Janeiro, Brazil. Int J Gynecol Cancer 2007;17:651–60.
23. Hildesheim A, Herrero R, Castle PE, Wacholder S, Bratti MC, Sherman ME, et al.. HPV co-factors related to the development of cervical cancer: results from a population-based study in Costa Rica. Br J Cancer 2001;84:1219–26.
24. Schiffman M, Castle PE, Jeronimo J, Rodriguez AC, Wacholder S. Human papillomavirus and cervical cancer. Lancet 2007;370:890–907.
25. Clifford GM, Smith JS, Plummer M, Munoz N, Franceschi S. Human papillomavirus types in invasive cervical cancer worldwide: a meta-analysis. Br J Cancer 2003;88:63–73.
26. Skiba D, Mehlhorn G, Fasching PA, Beckmann MW, Ackermann S. Prognostic significance of serum antibodies to HPV-16 L1 virus-like particles in patients with invasive cervical cancer. Anticancer Res 2006;26:4921–6.
27. Heim K, Widschwendter A, Pirschner G, Wieland U, Awerkiew S, Christensen ND, et al.. Antibodies to human papillomavirus 16 L1 virus-like particles as an independent prognostic marker in cervical cancer. Am J Obstet Gynecol 2002;186:705–11.
28. Sankaranarayanan R, Thara S, Esmy PO, Basu P. Cervical cancer: screening and therapeutic perspectives. Med Princ Pract 2008;17:351–64.
29. Cuzick J, Arbyn M, Sankaranarayanan R, Tsu V, Ronco G, Mayrand MH, et al.. Overview of human papillomavirus-based and other novel options for cervical cancer screening in developed and developing countries. Vaccine 2008;26(suppl 10):K29–41.
30. Hsieh FY, Lavori PW. Sample-size calculations for the Cox proportional hazards regression model with nonbinary covariates. Control Clin Trials 2000;21:552–60.