Volume 108, Issue 1 , Pages 74-75, January 2010
Human papillomavirus genotypes in invasive cervical cancer in Jordan
Article Outline
Keywords: Cervical cancer, Genotypes, Human papillomavirus, Jordan
Cervical cancer is the second most common cancer affecting women worldwide [1], with persistent infection by high-risk human papillomavirus (HPV) having an important role in cervical carcinogenesis [2]. Knowledge of HPV genotypes associated with invasive cervical carcinoma is necessary for determining the impact of new HPV vaccines on the incidence of these lesions.
An updated meta-analysis of the worldwide distribution of HPV types associated with both invasive cervical cancer and high-grade squamous intraepithelial lesions was recently published [3]. A total of 14
595 cases of invasive cervical cancer revealed HPV 16 to be the most common type on all continents, with HPV 18 the second most common. Types 31, 33, 35, 45, 52, and 58 were the next most common types, although there was regional variation in the relative importance of each of these 6 types. Data from the Middle East were scarce; thus, the objective of the present study was to determine the HPV genotypes involved in invasive cervical cancer in Jordan.
The archives of the Pathology Department at King Hussein Cancer Center, Amman, Jordan, were searched for cases of invasive cervical cancer; all cases accessioned at the time of diagnosis between 2003 and 2007, and with available paraffin blocks, were analyzed.
Using the Extra DNA Tissue kit (Sacace Biotechnologies, Como, Italy) according to the manufacturer's instructions, DNA was extracted from the paraffin blocks. The adequacy and the integrity of extracted DNA were assessed via spectrophotometry and polymerase chain reaction (PCR) for the gene encoding GAPDH.
An HPV typing kit (Sacace Biotechnologies, Como, Italy) containing 4 mixes of multiple primers—types 16, 31, 33, and 35; types 18, 39, 45, and 59; types 52, 56, 58, and 66; and types 6 and 11—was used. Amplification was followed by electrophoresis and band identification using an ultraviolet transilluminator. Negative results were invalidated if the internal control (the gene encoding β-globin) was absent. Positive and negative controls were included in each run.
Forty-eight cases of invasive cervical cancer with 54 paraffin blocks available were identified; 7 cases failed to produce adequate DNA. Patient age in the remaining 41 cases ranged from 37 to 80years, with a median group of 45–49years. There were 40 cases of squamous cell carcinoma and 1 of adenocarcinoma.
The HPV types obtained are shown in Table 1. Multiple infections in a single patient were common in the present study, with 14 patients (34.1%) harboring 2 or 3 types simultaneously. The single case of adenocarcinoma involved types 16 and 18. This combined type was found in 7 cases, with types 16 and/or 18 found in 31 (75.6%) overall. Thus, singly or in combination, the other HPV types were responsible for approximately 25% of cervical cancer cases. The next most common types were 39, 56, 45, 52, and 33.
Table 1. Number of cases according to HPV type.a
| HPV type | Cases (n=41) |
|---|---|
| 16 | 28 (68.3) |
| 18 | 10 (24.4) |
| 39 | 4 (9.8) |
| 56 | 4 (9.8) |
| 45 | 3 (7.3) |
| 52 | 3 (7.3) |
| 33 | 2 (4.9) |
| 31 | 1 (2.4) |
| 35 | 1 (2.4) |
| 58 | 1 (2.4) |
| 59 | 1 (2.4) |
| 66 | 0 (0.0) |
| 6 | 0 (0.0) |
| 11 | 0 (0.0) |
aValues are given as number (percentage). |
In the present study, type-specific primers were used, which had a higher sensitivity when applied to tissue biopsy than did the general primers used in most earlier studies. However, the present study was limited by the small number of samples available for study, in addition to the fact that it involved a referral center with no control over the processing or storage of the referred tissue blocks. Furthermore, only limited epidemiologic information on the study population was available.
Nevertheless, HPV types 16 and/or 18 were found in approximately 75% of cases of invasive cervical cancer, which is similar to the rates in Europe, North America, Australia, Algeria, and Morocco [3], [4], [5]. The relative importance of other high-risk types was slightly different from that reported in other studies, with types 39 and 56 more common than others—in contrast to findings from the HPV worldwide type distribution meta-analysis, where these types were not present among the 6 most common after types 16 and 18 (in Europe, type 56 was the eighth most common) [3]. Additionally, types 31, 33, 35, and 58 were less common in the present study. These discrepant results may be explained by the small number of specimens studied and the fact that regional variations exist in the relative importance of HPV types; for example, type 58 is the third most common type in Asia, but in other parts of the world it is the least common.
Multiple high-risk HPV types were found in approximately 34% of cases, which is consistent with results from several studies [6]. The present study showed that HPV 16 and HPV 18 are the most common types associated with cases of invasive cervical cancer in Jordan.
Conflict of interest
The authors have no conflicts of interest.
References
- . Introducing HPV vaccine in developing countries – key challenges and issues. N Engl J Med. 2007;10;356(19):1908–1910
- Epidemiologic classification of human papillomavirus types associated with cervical cancer. N Engl J Med. 2003;6;348(6):518–527
- Human papillomavirus type distribution in invasive cervical cancer and high-grade cervical lesions: a meta-analysis update. Int J Cancer. 2007;121(3):621–632
- Cervical carcinoma in Algiers, Algeria: human papillomavirus and lifestyle risk factors. Int J Cancer. 2005;113(3):483–489
- . El Mzibri M, Amrani M, Belabbas MA, Lazo PA. Human papillomavirus DNA in cervical lesions from Morocco and its implications for cancer control. Clin Microbiol Infect. 2003;9(2):144–148
- Multiple high risk HPV infections are common in cervical neoplasia and young women in a cervical screening population. J Clin Pathol. 2004;57(1):68–72
PII: S0020-7292(09)00506-2
doi:10.1016/j.ijgo.2009.08.025
© 2009 Elsevier B.V. All rights reserved.
Volume 108, Issue 1 , Pages 74-75, January 2010
