Papillomavirus DNA in cervical carcinoma specimens from central China

HPV prevalence, E6 sequence variation and physical state of HPV16 isolates from patients with cervical cancer in Sichuan, China

OBJECTIVES

Infection with high-risk human papillomavirus (hr-HPV) is an important factor associated with cervical cancer. The genetic mutation of HPV16 E6 and integration of HPV16 DNA in the cervical carcinoma tissues are considered important genetic changes in cervical lesion progression. But the studies of hr-HPV epidemiology are relatively less in the area of Sichuan, China. Therefore, we investigated the prevalence of 9 high-risk subtypes and analyzed the genetic mutation characteristic of HPV16 E6 and physical state of HPV16 DNA.

METHODS

The fragments of L1 and E6 genes were amplified by PCR or nested PCR and then directly sequenced. Further, the multiplex PCR for HPV16 E2 and E6 genes was performed for detection of integration.

RESULTS

HPV16, 58 and 18 were prominent, accounting for 78.6%, 20.0% and 9.7%, respectively in 145 isolates. E6 variants revealed that the European (EP) prototype and East Asia (EA) strain were 26 (23.0%) and 34 (30.1%), respectively. Furthermore, there were 14 base substitutions in E6 regions of the study group, of which 12 resulted in amino acid changes and the rest was silent mutation. Significantly, the 240G substitution exactly located the P53 degradation site. Overall, 8 of 114 (7.0%) isolates only contained integrated HPV16 DNA, 43 (37.7%) only contained episomal DNA and 63 (55.3%) contained both integrated and episomal DNA. The proportion of disruption of an intact E2 gene in the patients with cervical cancer is much lower than that in the previous studies.

CONCLUSIONS

HPV16, 58 and 18 were mainly prevailing subtypes in patients with cervical cancer from Sichuan areas, China and EP/EA strains were predominant in these areas. Some mutations of E6 gene, which lead to the amino acid changes, may be more potentially carcinogenic and the proportion of disruption of an intact E2 gene is much lower.

Human papillomavirus 16 and 18 expression in conjunctival intraepithelial neoplasia

OBJECTIVE

To evaluate conjunctival intraepithelial neoplasia (CIN) and normal conjunctiva for the presence of human papillomavirus (HPV) DNA and for expression (as detected by the presence of mRNA) of the HPV E6 region.

DESIGN

Prospective, case-controlled study.

PARTICIPANTS

Ten consecutive patients who underwent CIN excision by one surgeon (CLK) and five age-matched control subjects who underwent retinal detachment repair at the Bascom Palmer Eye Institute.

METHODS

A reverse transcriptase in situ polymerase chain reaction (PCR) technique was used to search for the presence of HPV mRNA in CIN specimens from 10 consecutive patients who underwent CIN excision by one surgeon (CLK) at Bascom Palmer Eye Institute, as well as in clinically uninvolved conjunctival specimens from the same eyes of these patients. In addition, conjunctival specimens from five control subjects (age-matched to five of the cases), who had no clinically identifiable conjunctival disease and who underwent retinal detachment repair at the Bascom Palmer Eye Institute, were analyzed in a similar manner. The clinical diagnoses of CIN and normal conjunctiva were confirmed histopathologically in all cases by an ocular pathologist, who was masked as to the patients' clinical diagnoses, and the PCR testing was performed by an investigator (GJN) who was masked as to the clinical diagnoses.

RESULTS

HPV 16 DNA and mRNA were present in five CIN specimens, and HPV 18 DNA and mRNA were present in the other five CIN specimens; neither HPV 16 or 18 DNA nor mRNA were detected in any of the control specimens or in any of the clinically uninvolved conjunctival specimens (P < 0.001). In each of the CIN specimens, 20% to 40% of the dysplastic cells expressed the HPV E6 region.

CONCLUSIONS

HPV 16 or 18 DNA and mRNA corresponding to the E6 region were detected in all CIN specimens examined. HPV 16 or 18 DNA or mRNA was not present in any of the control or uninvolved conjunctival specimens. The consistency of the current findings with those reported for human cervical malignant lesions, and the fact that the protein encoded by the E6 region of HPV 16 and 18 has been shown to form a complex with the protein encoded by the host tumor suppressor gene p53, provide strong evidence for an etiologic role of HPV in the development of CIN.

Human papillomavirus type 18 is associated with less apoptosis in fibroblast tumours than human papillomavirus type 16

In human cervical neoplasia human papillomavirus (HPV) type 18 has a higher cancer/cervical intraepithelial neoplasia (CIN) prevalence ratio than HPV 16. Fibrosarcomas derived from rat fibroblasts transfected with HPV 16 or 18 genomes showed increased apoptosis compared with controls. However, HPV 18 was associated with significantly less apoptosis than HPV 16, affording one possible explanation for the more rapidly progressive cervical neoplasia associated with HPV 18.

Prevalence of human papillomavirus DNA sequences in an area with very high incidence of cervical carcinoma

To improve our understanding of the relationship and possible associations between human papillomavirus (HPV) infection and the development of cervical malignancies, the presence of multiple types of HPV DNA sequences in cervical carcinoma was determined in Chinese citizens living in two different geographical locations where the incidences of cervical carcinoma are either relatively low or extremely high. HPV DNA sequences were found in 88.5% (54 of 61) of Chinese cervical carcinoma patients living in Taiwan, where the prevalence of cervical carcinoma is 23.7 per 100,000 women. In contrast, in LueYang in Shanxi province, an area with a very high prevalence of cervical carcinoma (1,026 per 100,000 women), only 57.1% (28 of 49) of Chinese cervical carcinoma patients were found to be infected with genital HPV. This result seems to suggest that either the presence of HPV may have different implications in different populations or HPV infection may not be the only factor that determines the development of cervical carcinoma, at least in certain geographical areas. Recently acquired transient or chronic persistent HPV infection may have a different outcome with regard to cervical carcinogenesis. Alternatively, other factors, such as host determinants, may play a role in the development of cervical carcinoma.

Human papillomavirus type 18 associates with more advanced cervical neoplasia than human papillomavirus type 16

A type-specific, sensitive, polymerase chain reaction-based assay for human papillomavirus (HPV) types 6b, 11, 16, 18, and 33 was applied to 47 cervical carcinomas, 60 cases of cervical intraepithelial neoplasia (CIN), and 24 samples of histologically normal cervix. As expected, the combined incidence of the common high-risk genital HPVs (types 16 and 18) was high in carcinomas (79%) and CIN 2/3 (60%), low in CIN 1 (25%), and nonexistent in the normal controls. Analysis of the data by viral type and pathology revealed statistically significant differences that consistently pointed to an association of HPV 18 with more advanced disease than HPV 16. This was exemplified by calculation of the relative HPV frequency in squamous cancers and CIN 2/3 lesions, which gave cancer to CIN prevalence ratios of 1.2 for HPV 16 and 2.3 for HPV 18, a twofold difference suggesting the possibility that there is a greater risk of progression or a more rapid transition to malignancy associated with HPV 18. Furthermore, HPV 16 was associated with 2.5-fold more cancers showing squamous differentiation (58%) than HPV 18 (23%), but both types showed an identical prevalence of 41% in the clinically more sinister adenocarcinomas, indicating that there may be an association between HPV type and cancer cell differentiation.

Human papillomavirus type 16 in tumor tissue of low-stage squamous carcinoma of the uterine cervix in relation to ploidy grade and prognosis

BACKGROUND

The relationship among the presence of human papillomavirus (HPV) in tumor cells, DNA ploidy, and the prognosis of squamous cell carcinoma of the uterine cervix was studied.

METHODS

HPV 16 was detected using the polymerase chain reaction on paraffin-embedded material from 69 patients with Stage IB and IIA carcinoma of the uterine cervix. The presence or absence of HPV was related to age, survival, and ploidy status as measured by DNA flow cytometry. All patients were treated by radical surgery.

RESULTS

Thirty-four patients had HPV 16, and 35 did not. The mean age of the patients differed statistically significantly between the HPV-positive group (51.1 years) and the HPV-negative group (45.1 years, P = 0.015). No difference was found in the mean DNA index (1.21 versus 1.22, P = 0.85) or 5-year survival rate (85% versus 86%, P = 0.87) between the two groups.

CONCLUSIONS

The high prevalence of HPV 16 in cervical cancer, which appeared to be correlated with age (in combination with its presence in diploid and aneuploid tumors), indicated the important role of HPV 16 in the evolution of cervical cancer. However, using stepwise Cox regression analysis, the presence of HPV 16 had no additional prognostic value over lymph node metastases findings.

Prognostic factors in invasive cervical carcinomas associated with human papillomavirus (HPV). Quantitative data and cytokeratin expression

As a part of a larger programme to search for the prognostic factors in cervical cancer, quantitative morphometry, demonstration of AgNORs and expression of different cytokeratin polypeptides (SK2-27, SK1, A 53-B/A2) were used to study a series of 85 cervical squamous cell carcinomas, previously analysed for the presence of human papillomavirus (HPV) DNA by in situ hybridization and polymerase chain reaction (PCR). The following nuclear profile parameters were calculated: nuclear area, perimeter, maximum diameter, ellipsoidity (form Ell), regularity (form Ar) and roundness (form Pe). In each case, the number of small (< 3 microns), large (> 3 microns), the total number and the ratio large/small AgNORs were registered. The cancer cell density and the lymphoid cell density were assessed. In the survival analysis, neither the expression of different cytokeratin polypeptides or the pattern of cytokeratin staining proved to be an independent variable. Similarly, none of the nuclear profile parameters analysed possessed an independent prognostic value in the survival analysis. The ratio of large/small AgNORs proved to be a significant independent prognostic predictor (p = 0.0104), second only to the lymphoid cell density. Also the total number of AgNORs was a prognostic indicator. This suggests that AgNOR size and ratio reflect tumor proliferation also in cervical squamous cell carcinoma, as shown in other human malignancies. Similarly, the density of cancer cell nuclei proved to be an independent prognostic predictor (p = 0.0601) in that the tumours in patients with longer survival showed lower density of the nuclei.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of HPV-16 in cell lines and cervical lavage specimens by a polymerase chain reaction-enzyme immunoassay assay

A gene amplification method that combines the polymerase chain reaction with detection of amplified DNA in a solution hybridization/enzyme immunoassay (PCR-EIA) was developed for HPV-16 DNA. Samples were amplified with primers for the E7-E1 region of HPV-16. Amplified DNA products were identified and quantitated by hybridization in solution with a biotinylated RNA probe. Labeled DNA/RNA hybrids were measured semiquantitatively in an enzyme immunoassay using solid phase anti-biotin antibody and liquid phase B-d-galactosidase labeled monoclonal antibody against DNA-RNA hybrids. Enzyme bound to the solid phase was quantitated with a fluorogenic substrate. The assay was linear over 2 log10 dilutions of SiHa cells and the detection limit was three copies of HPV-16 genome. The sensitivity of PCR-EIA for detection of PCR amplified products compared favorably with slot and Southern blots using a 32P-labeled RNA probe. The assay was used to assess HPV-16 infection of uterine cervix in women attending a clinic for sexually transmitted diseases. Twenty-one of the 81 specimens (25.9%), obtained by cervicovaginal lavage, were positive for HPV-16 by PCR-EIA. The assay provides a convenient means to objectively measure HPV DNA amplified with PCR.

Amplification of human papillomavirus type 16 transforming genes from cervical cancer biopsies and lymph nodes of Hungarian patients

We have used a polymerase chain reaction (PCR) to examine cervical cancer biopsy specimens and pelvic lymph nodes for the presence of human papillomavirus type 16 (HPV 16) DNA. Of the 75 cervical specimens tested, 36 (48%) were positive for HPV 16 in the PCR. A total of 65 pelvic lymph nodes removed during radical surgery on 35 women were also analyzed. Lymph nodes originating from 19 patients whose cervical biopsy specimens were negative for HPV 16 seemed to lack HPV 16 sequences. For 16 women with positive PCR results for cervical biopsy specimens, 9 of 10 lymph node metastases were positive in the PCR, while 11 of their 36 histologically negative lymph nodes were also shown to contain HPV 16 DNA.

HPV in full thickness cervical biopsies: high prevalence in CIN 2 and CIN 3 detected by a sensitive PCR method

A new type-specific, sensitive, non-radioactive assay is described for the detection of human papillomavirus (HPV) DNA in tissues. Sequences within the E6 gene were amplified by the polymerase chain reaction (PCR), using primer pairs which clearly distinguish HPV types, including those with close sequence homology such as 6b and 11. The amplified DNA products were identified by non-radioactive oligonucleotide hybridization and restriction endonuclease mapping, and the method was sufficiently sensitive to detect between 3 and 5 SiHa cells (each containing 1-2 copies of HPV 16 DNA) amongst 10,000 non-HPV-containing cells. Frozen and archival paraffin sections were equally acceptable substrates for the reaction. The assay was applied to frozen sections of full thickness cervical epithelium from 60 cases of cervical intraepithelial neoplasia (CIN) and 24 normal cervical controls. HPV DNA was detected in 60 per cent of cases of CIN 3 and CIN 2, in 25 per cent of cases of CIN 1, and in none of the normal controls. Prevalence of HPV 16 was similar (approximately 50 per cent) in both CIN 2 and CIN 3, and in the whole series HPV 16 was almost five-fold more common than HPV 18. Low-risk HPV types were present in 5 per cent of CIN 1, but 0 per cent of CIN 2 and CIN 3 biopsies. The data emphasize the biological similarity of CIN 2 and CIN 3 lesions, and their divergence from CIN 1.

Human papillomavirus types 16 and 33, herpes simplex virus type 2 and other risk factors for cervical cancer in Sichuan Province, China

Cancer of the cervix is relatively common in China, but has been investigated epidemiologically in only a few studies. In the hospital-based case-control study reported here, we investigated the role of various lifestyle and dietary factors, as well as infection with human papillomavirus (HPV) types 16 and 33 and herpes simplex virus type 2 in the aetiology of invasive cervical cancer. The study was conducted in Sichuan province, and involved 101 cases with histologically-confirmed cervical cancer recruited from the gynaecological oncology clinic of the West China University Hospital, and 146 controls recruited from patients attending the gynaecology clinic of the same hospital. Risk of cervical cancer was greatly increased in association with infection with HPV 16/33, the adjusted odds ratio for those with evidence of infection being 32.9 (95% CI 7.7-141.1). In contrast, infection with HSV 2 was not associated with a significantly altered risk of cervical cancer. Indices of sexual history and of dietary habits also showed no association with risk of cervical cancer, while good personal and genital hygiene were associated with markedly reduced risk. Although the results of this study are consistent with a causal role for HPV in the aetiology of cervical cancer, bias or increased viral expression following malignant transformation cannot be excluded as explanations for the strong positive association.

Oligonucleotide primers for DNA amplification of the early regions 1, 6, and 7 from human papillomavirus types 6, 11, 16, 18, 31, and 33

Human papillomavirus (HPV) type-specific sequences required for polymerase chain reaction (PCR) mediated amplification of HPV DNA sequences are presented. One primer pair within the E1 open reading frame (ORF) was shared by HPV 6, HPV 11, HPV 16, and HPV 31, whereas the other primer pair within the E1 ORF was specific for HPV 16. Eight primer pairs from the E6 and E7 ORFs specifically detected HPV 6, HPV 16, HPV 18, and HPV 33 sequences. This system has been used for detection of HPV DNA in biopsies, cytological smears and sections of formalin-fixed tissues.

Prognostic significance of human papillomavirus (HPV) type and nuclear DNA content in invasive cervical cancer

Eighty-one women treated for an invasive squamous cell carcinoma of the uterine cervix during the period from 1964 to 1987 were studied to assess the prognostic value of human papillomavirus (HPV) types 6,11, 16 and 18, as well as the nuclear DNA ploidy pattern, analyzed using HPV amplification by polymerase chain reaction (PCR) and flow cytometry, respectively. The mean age of the women was 57.7 ± 13.4 years, and the mean follow-up until the patients death or January 1990 was 99 ± 87 months. Altogether, 46 women died; 38 (82.6%) of these deaths were due to cervical cancer. The 5-year survival was significantly correlated with age (P= 0.01), and the FIGO stage of the tumors (P= 0.015), but not with tumor differentiation. Diploid tumor was found in 40 (63.5%) cases, and aneuploid in 23 (36.5%) cases. A DNA index 3= 1.5 was found in 47.8% (11/23) of the cases of aneuploid tumors. The 5-year survival rate in diploid tumors was 60.0% (21/35), as compared to 54.5% (12/22) in aneuploid ones, and in patients with a DNA index of < 1.5, the 5-year survival rate was 58.7% (27/46), as compared to 54.5% (6/11) in those with a DNA index ≥ 1.5. Amplified HPV DNA was found in 30 cases (37.0%) with the pairs of HPV DNA primers for HPV types of 6, 11, 16 and 18. When repeated with the anticontamination primers, only 19 (23.5%) cases remained HPV DNA positive. HPV 16 was the most frequent type present in 57.9% (11/19) of the cases, followed by HPV 18 in 36.8% (7/19). Neither the HPV DNA-positivity nor HPV type proved to be of prognostic significance. The results suggest that despite an intimate association of HPV 16 and 18 in cervical carcinogenesis, the presence of their DNA in cancer biopsies does not seem to have any prognostic value. The most significant prognostic factors are still the age and the FIGO stage at diagnosis. Aneuploid tumors or those with DNA index ≥ 1.5 seem to have a slightly (not statistically significantly) impaired prognosis as compared with the diploid tumors and those with DNA index < 1.5.

Prevalence of human papillomavirus types 16 and 18 in cervical carcinomas: a study by dot and Southern blot hybridization and the polymerase chain reaction

Histologically classified biopsies from 83 women with invasive cervical carcinoma were analyzed by dot blot hybridization for human papillomavirus (HPV) types 16 and 18 infection. Sixty of the 83 (72.3%) were found to contain HPV DNA, of which 43 (51.8%) contained HPV 16 DNA, 12 (14.5%) contained HPV 18 DNA and 5 (6.0%) contained both HPV 16 and 18 DNAs. Southern blot analysis on 65 specimens gave similar results. Of 23 specimens negative by dot blot, 21 were tested by the polymerase chain reaction. Seventeen of the 21 were positive for HPV DNA, of which 13 contained HPV 16 DNA and 4 contained both HPV 16 and 18 DNAs. In all, 95.1% (77/81) were positive for HPV 16 and/or 18 DNA sequences.

In situ hybridization analysis of HPV DNA in cervical precancer and cervical cancers from China

A series of 103 cervical biopsies derived from 103 women during July 1958 to September 1963 from Beijing, China were investigated with in situ hybridization for the presence of HPV6, 11, 16, 18, 31 and 33 DNA. The mean age of the patients was 46.1 + 10.6 years with a range of 24-74 years. Morphological features of HPV infection were found in 80 (77.7%) biopsies. Invasive cervical cancer was diagnosed in 43 biopsies and cervical intraepithelial neoplasia CIN I, CIN II and CIN III in 9, 9, and 27 cases, respectively. A total of 63.1% (65/103) of the lesions had morphological features of HPV infections associated with CIN or invasive carcinomas. Altogether, 31.1% (32/103) of the biopsies were shown to contain HPV DNA. Of the cases showing HPV morphology, 43.1% were HPV DNA positive. HPV16 (30/32) was the most frequent type, followed by HPV11 and 18, whereas no lesions with HPV6, 31 or 33 were found. A total of 19/43 (44.2%) of the invasive carcinomas contained HPV DNA. HPV DNA positivity and the grade of CIN showed a statistically significant correlation (P = 0.0011). Our study demonstrated the presence of HPV in cervical lesions among Chinese women in the late 1950's and early 1960's when a single sexual partner was the rule and also supports the concept that HPV has as an important etiological role in cervical cancer, the highest risk being associated with HPV type 16. The applicability of in situ hybridization in retrospective assessment is emphasized.

Demonstration of multiple HPV types in normal cervix and in cervical squamous cell carcinoma using the polymerase chain reaction on paraffin wax embedded material

The prevalence of human papilloma virus (HPV) types 6, 11, 16 and 18 was investigated using the polymerase chain reaction on formalin fixed, paraffin wax embedded material in 19 cases of cervical squamous cell carcinoma and in 10 normal cervices. HPV DNA was detected in 16 of 19 carcinomas, with multiple types present in 11 of these. HPV 16 or 18, or both, were present in all cases in which HPV was shown. Six of 10 cases of normal cervix contained HPV; five of these contained two or more HPV types, including HPV 16 or 18, or both. This study shows the feasibility of using the PCR on paraffin wax embedded material and indicates a high rate of carriage of multiple HPV types in both normal and neoplastic cervix.

Detection of human papillomavirus deoxyribonucleic acid in the female genital tract

A total of 336 biopsies, scrapes and exfoliated cells from the cervix and from the lower genital tract were screened for human papilloma (HP) viral sequences of types 6, 11, 16 and 18 by Southern blot, dot blot and filter in situ (FISH) hybridizations with cloned 32P-radiolabeled HPV DNA probes. The specimens included cervical intraepithelial neoplasias (CIN I-III), carcinoma in situ and invasive carcinoma of the cervix and vagina, adenocarcinomas, vulvar and vaginal condylomata acuminata and healthy epithelial samples. The oncogenic HPV 16 was found in 46% of the cervical carcinomas. Most of the type 16 occurrences (75%) represented the third stage of inoperable cases. Similarly, HPV 18 was also most frequently present in this stage as well as in carcinoma in situ and in CIN III (25%, 18%). At the same time, in condylomata acuminata, types 6 and 11 were detectable in 88.7% of cares. In all, 13.5% of the normal samples harboured HPV DNA.