Integration of human papillomavirus types 16 and 18 in cervical adenocarcinoma.

AIMS: To determine which type of human papillomavirus (HPV) is associated with cervical adenocarcinoma and whether the virus was integrated or episomal in two continents. METHODS: Biopsy specimens from the UK (n = 16) and South Africa (n = 22) were analysed by non-isotopic in situ hybridisation (NISH) for HPV types 6, 11, 16, 18, 31, 33, and 35 on archival biopsy specimens using digoxigenin labelled probes. RESULTS: A total of 20 adenocarcinomas (53%) from both groups contained HPV DNA. In the UK group, seven and four cases contained HPV 18 (44%) and 16 (25%) respectively. In the South African group, nine cases contained HPV 18 (41%) while HPV DNA was not detectable in the other 13 cases. Hence HPV 18 was present in 80% of HPV positive adenocarcinomas. CONCLUSIONS: The HPV 16 or 18 genome was integrated in all viral positive cases. In two cases HPV 18 was also present in an episomal form. These data indicate that HPV integration is common to cervical adenocarcinoma in two continents by the same methodology. The lower prevalence of HPV 18 detection in the South African group may have been due to the presence of other or unsequenced HPV types.     

Human papillomavirus types 16 and 18 sequences in early cervical neoplasia

A total of 100 colposcopic biopsies from patients with abnormal Papanicolau's tests were surveyed for the presence of human papillomavirus (HPV) types 16 and 18 sequences by spot-blot hybridization. HPV 16 and 18 DNA sequences were detected in 58% of the biopsies. None of the cervical intraepithelial neoplasia grade I (CIN I) contained HPV 16 while 50% of the CIN III lesions (carcinoma in situ, CIS) contained HPV 16. HPV 18-related sequences were equally represented in CIN I, II, and III. Southern-blot hybridization of total undigested cellular DNA revealed the presence of HPV DNA sequences only in an episomal form. While the restriction enzyme patterns in HPV 16-positive samples were mostly identical to the originally cloned sequence, the restriction enzyme pattern for HPV 18-positive samples were different from that of HPV 18 but identical to each other. Furthermore, this DNA hybridized more strongly to HPV 18 under nonstringent conditions, suggesting a new type.     

Prognostic value of human papillomavirus types 16 and 18 DNA physical status in cervical intraepithelial neoplasia

The aim of this work was to assess the value of the physical status of human papillomavirus (HPV) DNA as a disease marker for cervical cancer development in a set of 248 DNA samples previously genotyped as HPV 16 or 18, by calculating the E2/E6 ratio through real-time PCR. There was a significant difference in integration status according to disease grade for both genotypes (p <0.001). Furthermore, especially for HPV 18, determining the DNA physical status could be a useful biomarker in predicting cervical cancer risk development, with a lower E2/E6 ratio clinically associated with the development of a precancerous lesion.     

Outcome in mild and moderate cervical dysplasias related to the presence of specific human papillomavirus types

In situ hybridization with biotinylated DNA viral probes (ISH-B) for human papillomavirus (HPV) types 6/11, 16, 18, 31, and 33 was used to study the outcome in 32 cases of mild and 21 cases of moderate cervical dysplasia with koilocytotic change that were followed for an average of 27 mo. The rates of regression, persistence, and progression for cervical intraepithelial neoplasia (CIN) I and CIN II were 50%, 41%, and 9%, and 43%, 48%, and 9%, respectively. While progression of HPV 16 CIN I and II lesions was observed, regression occurred in 80% (four of five) and 43% (three of seven) of CIN I and II HPV 16-positive lesions, respectively. Regression was also seen in lesions that contained HPV 31 or HPV 33. All of the HPV 18 lesions persisted. The findings are compared with those of previous studies. Since some of the assumed more aggressive viral types can regress when followed by cytologic and biopsy examinations, caution must be exercised when attempting to predict the clinical outcome based solely on the specific viral type present in a given CIN lesion.     

Detection of transforming gene regions of human papillomavirus type 16 in cervical dysplasias by the polymerase chain reaction

In a study of 29 cases of histologically confirmed, characterized colposcopically and cytologically, cervical intraepithelial neoplasias 48.3% (14/ 29) of biopsies were positive for human papillomavirus (HPV) type 16 DNA by polymerase chain reaction. We used two oligonucleotide primer pairs (position 215–514 and 606–805) flanking a 300 and a 199 base pair fragment from the early 6 (E6) and early 7 (E7) genes. The results were concordant both with the E6 and with the E7 regions. Of the amplified products 85.7% (12/14) could be confirmed; these carried 16 specific sequences by Southern blot hybridization. HPV 16 DNA was present in 6.7% (2/30) of the colposcopically directed cytologically normal matched control samples using the same methods.     

人乳头状瘤病毒16、18型变异及相关肿瘤

肿瘤的形成可由多种病毒引起[1],其一就是人类乳头状瘤病毒(Human papillomavirus,HPV).HPV是1949年从普通疣体浸出液中首次被观察到,1995年有研究证实HPV感染为宫颈癌的致病病原体.研究显示:HPV16、18能促使人类鳞状上皮的增生.目前HPV16、18变异体的致瘤性受到各国学者的广泛关注.     

Human papillomavirus types 16 and 18 and the prognosis of patients with stage I cervical cancer

OBJECTIVE:

This study sought to evaluate the prevalence of human papillomavirus (HPV) types 16 and 18 in women with clinical stage IB cervical cancer treated by radical hysterectomy with pelvic lymphadenectomy as well as to establish a correlation between HPV type and cancer prognosis.

METHODS:

A single-center cohort study was conducted with 86 patients who had undergone radical hysterectomy for stage I cervical cancer. Prognostic factors and the presence of HPV 16 and 18 were analyzed using a polymerase chain reaction assay. A univariate analysis using Kaplan-Meier curves was conducted to estimate survival.

RESULTS:

The prevalence of HPV 16 in the study group was 65.3%, and the prevalence of HPV 18 was 33.3%. The prevalence of infection with both viruses was 26.9%. Overall survival at 5 years was 91% among women with HPV 18 and 96% among those without this virus type (p = 0.133). Among the women with HPV 16, the overall survival was 94%, whereas this rate was 96% among those without this virus type (p = 0.663). Disease-free survival was unaffected by the presence of HPV type 16 or 18.

CONCLUSION:

In the present study, despite the high prevalence of HPV types 16 and 18, the presence of these virus types did not affect the prognosis of patients with stage I cervical cancer who underwent radical hysterectomy.     

Immunohistochemical detection of p53 in cervical epithelial lesions with or without infection of human papillomavirus types 16 and 18

Using formalin-fixed and paraffin-embedded cervical tissues, we examined infection with human papillomavirus (HPV) types 16 and 18 by Southern blot analysis following polymerase chain reaction (PCR), and the accumulation of p53 protein by immunohistochemistry in 30 cases of normal or metaplastic cervix, 17 cases of cervical intraepithelial neoplasia grade I (CIN I), 20 cases of CIN II, 37 cases of CIN III and 23 cases of invasive squamous cell carcinoma (ISCC). In addition, we examined the ratio of HPV-infected cells by in situ hybridization (ISH) and the alteration of p53 gene using PCR followed by single-strand conformation polymorphism (PCR-SSCP) in 2 cases of CIN III and 12 cases of ISCC, in which overexpression of p53 was immunohistochemically detected. HPV DNA was detected in 5 cases (16.7%) of normal or metaplastic cervix, 5 cases (29.4%) of CIN I, 9 cases (45.0%) of CIN II, 26 cases (70.3%) of CIN III and 15 cases (65.2%) of ISCC. Positivity for HPV in the groups of CIN III and ISCC was significantly higher than in the normal or metaplastic cervix (P<0.05). The accumulation of p53 was not detected in the normal or metaplastic cervix, CIN I and CIN II. High-level p53 accumulation was identified in basal and suprabasal atypical cells in 27.0% (10/37) of CIN III and in carcinoma cells in 43.5% (10/23) of ISCC cases, and low-level accumulation was identified in atypical cells of 35.1% (13/37) of CIN III and in carcinoma cells in 30.4% (7/23) of ISCC cases. The accumulation of p53 was found to coexist with infection by HPV in 17 (46.0%) of 37 CIN III cases and 12 (52.2%) of 23 ISCC cases, and high-level p53 accumulation was more frequently detected in HPV-positive ISCC cases. Either HPV infection or accumulation of p53 was found in 16.7% (5/30) of the cases of normal or metaplastic cervix, 29.4% (5/17) of CIN I, 45.0% (9/20) of CIN II, 86.5% (32/37) of CIN III and 87.0% (20/23) of ISCC cases. These results suggest that the inactivation of p53 function by HPV infection or alteration of p53 protein itself precedes the development of tumours with a fully malignant and invasive phenotype and plays an important role in tumorigenesis in the uterine cervix. ISH study provided no correlation between the degree of immunohistochemical positivity for p53 and the ratio of HPV-positive cells in the same lesions. PCR-SSCP detected the alteration of p53 gene in at least 4 cases of ISCC, 2 of which were accompanied by HPV infection.     

Relationship between cervical disease and infection with human papillomavirus types 16 and 18, and herpes simplex virus 1 and 2

Persistent infection with high‐risk HPV, particularly Type HPV 16 and 18, is necessary in the development of cervical cancer, but apart from HPV infection, other causative factors of most cervical cancers remain unknown. The aim of this study was to determine the prevalence of HPV 16 and HPV 18 and HSV 1 and HSV 2 in cervical samples, and to assess the role of HSVs in cervical carcinogenesis. Two hundred thirty‐three healthy controls and 567 cases (333 of cervicitis, 210 of cervical intraepithelial neoplasia, and 24 of squamous cell carcinoma) in cervical exfoliative cells were tested for HPV 16, HPV 18, HSV 1, and HSV 2 DNA using the triplex real‐time polymerase chain reaction method. In contrast to healthy women, positive rate of HPV is related significantly to cervical lesions (odds ratios (ORs) = 4.1, P < 0.01 for cervical intraepithelial neoplasia; ORs = 24.9, P < 0.01 for squamous cell carcinoma), but not cervicitis (ORs = 2.3, P > 0.05). HSV 2 prevalence in cervical intraepithelial neoplasia and squamous cell carcinoma was higher than in healthy women (ORs = 4.9, P < 0.05 for cervical intraepithelial neoplasia; ORs = 4.7, P < 0.05 for squamous cell carcinoma). HSV 2 coinfection with HPV in cervical intraepithelial neoplasia and squamous cell carcinoma was strongly higher than in healthy women (ORs = 34.2, P < 0.01 for cervical intraepithelial neoplasia; ORs = 61.1, P < 0.01 for squamous cell carcinoma). The obtained results indicated that the presence of HPV is associated closely with cervical cancer, and that HSV 2 infection or co‐infection with HPV might be involved in cervical cancer development, while HSV 1 might not be involved. J. Med. Virol. 84:1920–1927, 2012. © 2012 Wiley Periodicals, Inc.     

Quantitative human papillomavirus 16 and 18 levels in incident infections and cervical lesion development

Human papillomavirus (HPV) RNA levels may be a more sensitive early indicator of predisposition to carcinogenesis than DNA levels. We evaluated whether levels of HPV‐16 and HPV‐18 DNA and messenger RNA (mRNA) in newly detected infections are associated with cervical lesion development. Female university students were recruited from 1990 to 2004. Cervical samples for HPV DNA, HPV mRNA, and Papanicolaou testing were collected tri‐annually, and women were referred for colposcopically directed biopsy when indicated. Quantitative real‐time polymerase chain reaction of L1 and E7 DNA and E7 mRNA was performed on samples from women with HPV‐16 and HPV‐18 infections that were incidently detected by consensus PCR. Adjusting for other HPV types, increasing E7 cervical HPV‐16 mRNA levels at the time of incident HPV‐16 DNA detection were associated with an increased risk of cervical intraepithelial neoplasia grade 2–3 (HR per 1 log₁₀ increase in mRNA = 6.36, 95% CI = 2.00–20.23). Increasing HPV‐16 mRNA levels were also associated with an increased risk of cervical squamous intraepithelial lesions; the risk was highest at the incident positive visit and decreased over time. Neither HPV‐16 E7 DNA levels nor HPV‐18 E7 DNA nor mRNA levels were significantly associated with cervical lesion development. Report of >1 new partner in the past 8 months (relative to no new partners) was associated with increased HPV mRNA (viral level ratio [VLR] = 10.05, 95% CI = 1.09–92.56) and increased HPV DNA (VLR = 16.80, 95% CI = 1.46–193.01). In newly detected HPV‐16 infections, increasing levels of E7 mRNA appear to be associated with an increased risk of developing cervical pre‐cancer. J. Med. Virol. 81:713–721, 2009 © 2009 Wiley‐Liss, Inc.     

Distribution of human papillomavirus genotypes in women with high-grade cervical intraepithelial lesions and cervical carcinoma and analysis of human papillomavirus-16 genomic variants

AimTo analyze the distribution of high-risk human papillomavirus (HR-HPV) genotypes and the diversity of HPV-16 genomic variants in Croatian women with high-grade squamous intraepithelial lesions (HSIL) and cervical carcinoma.MethodsTissue biopsy specimens were obtained from 324 women with histopathologically confirmed HSIL or cervical carcinoma, 5 women with low-grade SIL, and 49 women with negative histopathology. HR-HPV DNA was detected with Ampliquality HPV-type nucleic-acid hybridization assay, which identifies 29 different HPV genotypes. HPV-16 genomic variants were analyzed by an in-house sequencing.ResultsThe most common HPV type in women with HSIL was HPV-16, detected in 127/219 (57.9%) specimens. HPV-16 was also the dominant type in squamous cell cervical carcinoma (46/69 or 66.7%) and in adenocarcinoma (18/36 or 50.0%). Out of 378 patients, 360 had HR-HPV (282 single infections and 79 multiple infections), 3 (0.8%) patients had low-risk HPV, and 15 (4%) tested negative. HPV-16 variants were determined in 130 HPV-16 positive specimens, including 74 HSIL and 46 carcinoma specimens. In HSIL specimens, 41 distinct variants were found, 98.6% belonging to the European branch and 1.4% belonging to the African branch. In cervical carcinoma specimens, 95% isolates grouped in 41 variants belonging to the European branch, one isolate (2.5%) belonged to the North American, and one (2.5%) to the Asian-American branch.ConclusionHPV-16, mainly belonging to the European branch, was the most frequent HPV genotype in women from Croatia with histologically confirmed HSIL and cervical cancer.

Cervical cancer is the second leading cause of death in women in low-income countries (1). Persistent infection with particular human papillomavirus (HPV) genotypes is a necessary but not a sufficient requirement for the development of cervical cancer (2). HPV DNA is detected worldwide in nearly all specimens of invasive cervical cancer, including squamous cell carcinomas, adenocarcinomas, and the majority (>95%) of immediate cervical cancer precursors (3). An epidemiological study by Bosch et al (4) has shown that the most common HPV genotypes in HSIL and squamous cell carcinomas were HPV-16, HPV-18, HPV-31, HPV-33, HPV-35, HPV-45, HPV-52, and HPV-58, with a combined worldwide relative contribution of 91% and the predominant role of HPV-16, HPV-18, and HPV-45 in cervical adenocarcinoma.HPV genomic variants are defined as the viruses that vary by 2% or less in specified regions of the genome, and some display different oncogenicity (5). HPV-16 heterogeneity has been extensively investigated (6-12), and HPV-16 genomic variants have been identified to belong to five main branches: European, Asian-American, two African branches, and an Asian branch (13). Two subsequent studies expanded these classifications and reported a new branch: North American 1 (14,15).Epidemiological studies have shown that non-European HPV-16 variants may promote viral persistence and disease progression (16-19). HPV-16 E6 variants, including the European HPV-16 T350G variant in the E6 gene, were detected up to 20 times more often in patients with high-grade cervical disease compared with controls. A novel HPV-16 variant, identified in Croatia, harboring a 63-bp in-frame duplication in the E1 gene, was presumed to be of reduced oncogenicity (11).According to the several national or regional studies in women with normal and abnormal cytology, HPV-16 is the most common high-risk genotype in Croatian women (20-27). However, none of these studies involved HPV genotyping in tissue specimens, and the majority were performed in general population with a small number of women with histologically confirmed HSIL or cervical cancer. The genomic diversity of high-risk HPV genotypes in Croatia has not been studied to date. On the other hand, recommended, non-mandatory, free-of-charge, nine-valent HPV vaccine is available in Croatia and is intended for vaccination of both women and men aged 14 to 25 years (28).The aims of this study were to analyze the distribution of high-risk HPV genotypes (HR-HPV) in women with histologically confirmed HSIL and cervical carcinoma and to analyze the genomic diversity of HPV 16 in HSIL in comparison with invasive cervical cancer.     

Rapid real time PCR to distinguish between high risk human papillomavirus types 16 and 18

Aims—To assess the validity and practicality of real time polymerase chain reaction (PCR) for human papillomavirus (HPV) testing in combination with liquid based cytology samples for cervical screening.Methods—Real time PCR using consensus (GP5+/6+) and type specific primers was developed to detect genital HPV types. This provides rapid, efficient amplification followed by denaturation of the product and computer analysis of the kinetics data that are generated. Liquid based cytology samples were obtained from patients attending routine cervical screening clinics. DNA was extracted from the residual cellular suspension after cytology using spin columns.Results—Real time PCR successfully distinguished between HPV-16 and HPV-18 on the basis of amplification with consensus primers followed by DNA melting temperature (T_m) analysis. Sensitivities of one to 10 copies of HPV-16 (mean T_m = 79.4°C; 2 SD, 0.8) and four to 40 copies of HPV-18 (mean T_m = 80.4°C; 2 SD, 0.4) were obtained. In a mixed population of SiHa and HeLa cells containing known copy numbers of HPV-16 and HPV-18 genomes, HPV-16 and HPV-18 products were clearly separated by T_m analysis in mixtures varying from equivalence to 1/1000. Together with detailed melt analysis, type specific primers from the same region of the L1 gene confirmed the differential ability of this system. The method was applied to 100 liquid based cytology samples where HPV status using conventional GP5+/6+ PCR was already known. There was 95% agreement between the methods, with 55 positives detected by conventional PCR and 59 with real time PCR. The method was then tested on 200 routine liquid based cytology samples. Approximately 10% were positive by real time PCR, most of which were classified as HPV-16 by detailed melt analysis. Thirteen (6.8%) HPV positives were identified in 189 samples showing no evidence of cervical cytological abnormality.Conclusions—Real time PCR is a rapid, efficient method for the detection of HPV with the separation of HPV-16 and HPV-18 on the basis of differential T_m. Preliminary results suggest it could prove useful if HPV testing is added to cervical screening programmes.     

肺癌组织中人乳头瘤病毒16和18型DNA相关序列的检测

采用聚合酶链反应技术（ＰＣＲ）及用ＰＣＲ法制备生物素标记探针的斑点杂交法,检测５０例肺癌、１８例肺良性病及４例胎肺组织中高危险型人乳头瘤病毒（ＨＰＶ）１６、１８型ＤＮＡ相关序列,以探讨ＨＰＶ与肺癌之间发生的关系。结果３２％的肺癌组织中检测出ＨＰＶ１６、１８ＤＮＡ,其中ＨＰＶ１６ＤＮＡ阳性１０例,ＨＰＶ１８ＤＮＡ阳性５例,１例同时含ＨＰＶ１６、１８ＤＮＡ。２７例鳞癌组织中ＨＰＶＤＮＡ阳性率为４８．２％。而肺良性病组织及胎肺组织均未发现ＨＰＶＤＮＡ。ＨＰＶＤＮＡ呈阳性的肺癌患者绝大多数为重度吸烟者。提示原发性肺癌的发生可能与ＨＰＶ感染有关。     

T-helper epitopes identified within the E6 transforming protein of cervical cancer-associated human papillomavirus type 16

The E6 oncoprotein of human papillomavirus type 16 (HPV16 E6) produced by tumor cells of HPV16-associated cervical carcinoma is poorly immunogenic in patients, but nonetheless is a tumor-specific antigen to which therapeutic vaccine strategies may be directed. To investigate the subunit immunogenicity of E6 protein at the T-helper cell level, we immunized mice with overlapping peptides spanning the entire 158 amino acid sequence. Two peptides recalled a proliferative response in lymph node cells (LNC) from C57BL/6 (H-2b)-immunized mice. One of these peptides also recalled proliferative responses in the context of 5/5 other major histocompatibility complex (MHC) class II haplotypes, indicating a "promiscuous" T-epitope. Minimal consensus motif analysis identified the epitopes as 60VYRDGNPYA68 and 98GYNKPLCDLL107. LNC from mice immunized with T-epitope proliferated in response to challenge with whole E6 protein. Immunization with E6 T-epitopes linked to B-epitopes of HPV16 E7 protein elicited specific antibody indicating that T-cells recognizing the T-epitopes provided cognate "help" for B-cells. LNC from mice co-immunized with E6 T-epitope and the major T-helper epitope of HPV16 E7 (48DRAHYNI54) proliferated comparably when challenged with the peptides individually indicating co-dominance of the two T-epitopes. The findings have implications for incorporation of E6 into a therapeutic vaccine.     

应用量子点荧光原位杂交技术检测人宫颈鳞癌中人乳头状瘤病毒16/18的感染

目的 探讨荧光标志物量子点在荧光原位杂交技术检测人宫颈癌组织中人乳头状瘤病毒16/18(HPV16/18)感染中的应用.方法 以量子点荧光原位杂交(QD-FISH)和显色原位杂交方法(CISH)分别检测80例宫颈鳞癌活检组织中HPV16/18的感染情况,对其结果进行统计学分析.结果 QD-FISH检测宫颈鳞癌活检组织中HPV16/18阳性率为88.8%(71/80),高于CISH检出的阳性率(80%,64/80),但差异无统计学意义(P=0.127),并且HPV16/18感染的阳性率随着宫颈癌级别的上升而上升.结论 QD-FISH检测HPV感染的灵敏性和特异性均高于CISH,可作为筛查宫颈癌的一种方法.     

P16INK4A和人乳头状瘤病毒检测对宫颈上皮高度病变的预测意义

目的 探讨在液基细胞学(TCT)未明确意义的不典型鳞状上皮细胞(ASCUS)中,P16INK4A免疫细胞化学染色和高危型人乳头状瘤(HR-HPV)检测对宫颈上皮内高度病变(HSIL)的预测意义.方法 应用免疫细胞化学方法检测P16INK4A在89例液基细胞学不典型鳞状上皮细胞(ASC-US 55例和ASC-H 34例)中的表达,用第二代杂交捕获法(HC-2)检测每一患者的13种HR-HPV DNA,并同组织病理诊断结果比较.结果 在89例ASCUS中,组织病理证实:HSIL(CIN2/3)22例,宫颈癌2例.占26.97%(24/89).P16INK4A免疫细胞化学染色阳性26例中,组织病理证实:CIN2/3 20例,宫颈癌2例,CIN1和宫颈炎4例;HC-2HR-HPV DNA检测阳性64例,组织病理证实:CIN2/3 21例,宫颈癌2例,CIN1和宫颈炎41例;差异有统计学意义(P<0.01).P16INK4A免疫细胞化学染色对宫颈鳞状上皮内高度病变(HSIL)的阳性预测值(PPV)和特异性(Sp)分别为84.62%和93.85%,明显高于HC-2 HR-HPV DNA检测的PPV 35.94%和Sp 36.92%.结论 在TCT-ASCUS中,P16INK4A特异免疫染色比HG2 HR-HPVDNA检测能够更可靠地鉴别宫颈良、恶性疾病,二者联合检测将会为病人提供一种更有效、更合理的处理方案.     

Molecular variants of human papillomavirus type 16 and 18 and risk for cervical neoplasia in Portugal

Persistent high-risk human papillomavirus (HPV) infection is considered as the central cause of invasive cervical cancer. Specific HPV 16 and 18 sequence variations were associated with an increased risk for progression. The purpose of this study was to analyze intratypic variations of HPV 16 and 18 within the E6 gene, MY09/11 and LCR regions, and to evaluate the risk of these variants for cervical neoplasia among Portuguese women. Cervical samples from 187 HPV 16-positive and 41 HPV 18-positive women with normal epithelium, cervical intraepithelial neoplasia, or invasive cervical cancer were amplified by type-specific PCR, followed by sequence and phylogenetic analysis. Sixteen new HPV 16 and 18 patterns are described in this paper. European HPV 16 variants were the most frequent (74.3%), particularly Ep-T350 (44.4%), followed by African (16.1%), and Asian-American (9.6%). Non-European HPV 16 variants were more frequent in pre-invasive lesions than in normal tissue and low-grade lesions. However, when analyzed separately, only African variants were associated significantly with an increased risk for cervical cancer. For HPV 18, the AsAi variant showed a trend, which was not statistically significant to an enhanced oncogenicity. European variants seemed to be significantly associated with a lower risk for cervical cancer development. The distribution of HPV 16 and 18 variants was not related to age or race among women living in the same geographical region. Knowledge of variants will be important for risk determination as well as for designing primers or probes for HPV detection methods, and for appropriate cervical cancer prevention strategies.