Human papillomavirus infection and invasive cervical cancer in Paraguay

Abstract

HPV types 16 and 18 have been categorized as human carcinogens based on their strong associations with cervical cancer in previous case-control studies. Recent IARC studies in the Philippines, Thailand and Morocco show strong associations between invasive cervical cancer and less common HPV types, including HPV 31, 33, 45, 51, 52 and 58. We present results of a further IARC case-control study conducted in Asunció n, Paraguay, to examine the association between specific HPV types and invasive cervical cancer as well as risk factors other than HPV. One-hundred thirteen incident histologically confirmed invasive cervical cancer cases and 91 age-matched hospital controls were recruited. A standardized questionnaire was administered to investigate known and suspected risk factors for cervical cancer. For HPV status determination, cervical biopsy specimens from case subjects and exfoliated cervical cells from control subjects were obtained. HPV DNA was ascertained using a GP5؉/6؉ PCR-based assay capable of detecting more than 33 HPV types. Overall HPV prevalence was 97% in the cervical cancer cases and 20% in the control subjects. As a single infection, HPV 16 was the predominant type with a prevalence of 48% among case subjects and 5.5% among control subjects. Cervical cancer is the second most common cancer among women in the world and in developing countries. In the early 1990s, the worldwide age-standardized incidence rates of cervical cancer ranged from 2.6/100,000 women in Qidong, China, to 67.2/100,000 women in Harare, Zimbabwe (Parkin et al., 1997). Paraguay, a South American country with an estimated population of 4.8 million, had a notably high cervical cancer incidence rate of 41.1/100,000 in 1990. This is the second highest cervical cancer incidence rate in South America after Bolivia yet higher than in Brazil, Ecuador and Colombia. (IARC, 1998) Certain human papillomavirus (HPV) types have been demonstrated to be the primary etiological agents for cervical cancer (IARC, 1995). HPV types 16 and 18 have been categorized as human carcinogens based on their strong associations with cervical cancer (Munoz et al., 1992; IARC, 1995). IARC-conducted invasive cervical cancer case-control studies in the Philippines (Ngelangel et al., 1998), Thailand (Chichareon et al., 1998, Brazil (Eluf-Neto et al., 1994) and Morocco (Chaouki et al., 1998) confirmed the strong associations between invasive cervical cancer and HPV types 16 and 18 and showed similar strong associations with less common HPV types, including HPV 31, 33, 45, 51, 52 and 58. Further data on the association between these less common HPV types and invasive cervical cancer risk are currently needed.We present results of an IARC study of invasive cervical cancer conducted in Asunción, Paraguay. Our report examines the association between invasive cervical cancer and specific HPV types as well as other risk factors of invasive cervical cancer. MATERIAL AND METHODS SubjectsBetween December 1988 and May 1990, 116 patients with invasive cervical cancer and 1...

HPV types and cofactors causing cervical cancer in Peru

“…This is consistent with similar studies carried out by the IARC in Spain and Colombia (Muñoz et al, 1992;Bosch et al, 1993), the Philippines (Ngelangel et al, 1998), Thailand (Chichareon et al, 1998), Brazil (Eluf-Neto et al, 1994, Morocco (Chaouki et al, 1998) and Paraguay (Rolón et al, 2000). Percentage of the single and multiple types were calculated based on the total HPV positive women.…”

Against which human papillomavirus types shall we vaccinate and screen? the international perspective

“…Detailed methods of case and control selection are described in the original papers. [7][8][9][10][11][12][13][14][15] …”

“…5 To assess the geographic distribution of HPV types in invasive cervical cancer and the risk linked to the various HPV types, the IARC carried out an international survey of cervical cancer specimens in 22 countries 4,6 and a multicenter case-control study in 11 countries around the world. [7][8][9][10][11][12][13][14][15] These studies were carried out using the same protocol and sensitive PCR assays for the detection of HPV DNA in a central laboratory.HPV prophylactic vaccines for the most common types (HPVs 16 and 18) are now being tested in various populations with promising results as they have been shown to be safe and to induce high titers of neutralizing antibodies that prevent HPV infection and cervical intraepithelial neoplasia (CIN). 16 -18 Although there is some evidence of cross-reactivity among certain HPV types, 19 this appears to account for Ͻ1% of antibody reactivity, indicating that protection to infection is type-specific.…”

“…5 To assess the geographic distribution of HPV types in invasive cervical cancer and the risk linked to the various HPV types, the IARC carried out an international survey of cervical cancer specimens in 22 countries 4,6 and a multicenter case-control study in 11 countries around the world. [7][8][9][10][11][12][13][14][15] These studies were carried out using the same protocol and sensitive PCR assays for the detection of HPV DNA in a central laboratory.…”

Epidemiologic Classification of Human Papillomavirus Types Associated with Cervical Cancer

“…There is, however, no consensus concerning the categorization of many HPV types with low prevalence according to risk. Moreover, the number of putative high-risk types varies from 13 to 19, and only 11 HPV types (16,18,31,33,35,39,45, 51, 52, 56, and 58) are consistently classified as entailing high risk. [8][9][10][11] For these reasons, clear-cut criteria for classifying HPV types into low-risk and high-risk groups are needed.…”