Analysis of p53, p16(INK4a), pRb and Cyclin D1 expression and human papillomavirus in primary ovarian serous carcinomas

AIM

To evaluate the prognostic relevance of key cell cycle regulatory proteins p53, p16(INK4a), pRb and Cyclin D1 expression, the presence of high risk HPVs and their association with clinicopathological parameters and the clinical follow up in ovarian cancer patients.

METHODS

53 cases of primary ovarian serous carcinomas were immunohistochemically examined for the expression of p53, p16(INK4a), pRb and Cyclin D1 proteins. Tumor DNA was extracted from paraffin blocks and subjected to HPV 16 and 18 testing. The association between HPV 16 and 18 E6 oncoprotein and cell cycle proteins expression in ovarian carcinomas also was evaluated by immunohistochemistry.

RESULTS

We demonstrated that a majority of moderately and poorly differentiated ovarian carcinomas are characterized by strong expression of p53 and p16(INK4a) proteins. In contrast, strong staining with cyclin D1 antibody was observed in well differentiated tumors. The correlation between strong p53, pRb, Cyclin D1 and clinical stages of disease was also observed. We show that patients with high positivity for p53, p16(INK4a) and Cyclin D1 had a poor prognosis and reduced overall survival. The presence of HPV 16/18 DNA was detected in 17% of ovarian carcinomas. The tumor tissues that reacted positively to HPV E6 antibody in focal and diffuse manners had also significantly low p53 expression profile.

CONCLUSION

These findings suggest that p53, p16(INK4a) and Cyclin D1 expression and HPV infection may represent a promising tool toward the identification of ovarian cancer patients with poorer prognosis and shorter survival who might therefore need a more aggressive therapy and HPV screening.

Targeted cellular uptake and siRNA silencing by quantum-dot nanoparticles coated with β-cyclodextrin coupled to amino acids

Quantum dots (QDs) have the potential to serve as photostable beacons to track siRNA delivery, which is fast becoming an attractive approach to probe gene function in cells. In this paper, we synthesized QD nanoparticles coated with β-cyclodextrin (β-CD) coupled to amino acids with different surface charges (positive, negative, and neutral) through direct ligand-exchange reactions and used them to deliver siRNA. We found that these QDs are diffluent in biological buffer with high colloidal stability and have strong optical emission properties similar to those of tri-n-octylphosphine oxide (TOPO)-coated QDs and also have a long fluorescence lifetime (12.5 ns for L-His-β-CD-coated CdSe/ZnSe QDs). The results of in vitro cytotoxicity and internalization of these modified QDs in normal and cancer cells showed that the β-CD coupled to amino acid outlayers greatly improved the biocompatibility of QDs, and conferred with lower cytotoxicity even at very high concentration. In particular, the L-His-β-CD-coated CdSe/ZnSe QDs presented lower cytotoxicity to these cells (CC(50) value is 180.6±3.4 μg mL(-1) in ECV-304 cells for 48 h). Transmission electron microscope (TEM) images showed that the QDs were localized in vesicles in the cytoplasm of the cells. Furthermore, compared with existing transfection agents, gene-silencing efficiency of the modified QDs was slightly improved for HPV18 E6 gene in HeLa cells by gel electrophoresis analysis. Finally, the unique optical properties of QDs allow visible imaging of siRNA delivery in live cells. Taken together, our study not only provides new insights into the mechanisms of amino acid mediated delivery, but also greatly facilities the monitoring of gene-silencing studies.

Evaluation of the HPV L1 capsid protein in prognosis of mild and moderate dysplasia of the cervix uteri

Cervical intraepithelial neoplasia (CIN) can be detected in the cytologic smears years before invasive squamous cancer arises, but no reproducible morphologic criteria exist to predict behavior of cervical lesions. The possibility of predicting the clinical course of cervical lesions could be of high value in clinical practice and some women will spare of unnecessary treatment. HPV L1 capsid protein represents about 90% of the total protein on the surface of the virus and can be detected in mild to moderate dysplasia and rarely in severe dysplasia. The purpose of the study was to evaluate the use of immunodetection of HPV L1 protein on archival Pap smears with findings of mild and moderate dysplasia in predicting its clinical course. Immunochemical analyses with L1 antibody revealed positively stained nuclei of squamous epithelial cells in 56 of 114 smears (49.1%). The staining results were correlated with follow-up smears or with histologic verification. Regression (negativisation of the Pap smear for 24 months or longer) was noticed in 31 of 56 (55.4%) L1-positive cases and in 20 of 58 (34.5%) L1-negative cases. Persistent disease occured in 13 (23.2%) L1-positive cases and in 14 (24.1%) L1-negative cases. Progressive disease occured in 12 (21.4%) L1-positive cases and in 24 (41.4%) L1-negative cases. The difference in the clinical course between the L1-positive and L1-negative patients was statistically significant (p = 0.025). Also, the difference in the clinical course of the L1-negative staining in the under-30 and over-30 years age group was statistically significant (p = 0.04). For conclusion, our data confirm that immunostaining for HPV L1 capsid protein could offer prognostic information about mild and moderate intraepithelial cervical squamous lesions.

Identification of unusual E6 and E7 proteins within avian papillomaviruses: cellular localization, biophysical characterization, and phylogenetic analysis

Papillomaviruses (PVs) are a large family of small DNA viruses infecting mammals, reptiles, and birds. PV infection induces cell proliferation that may lead to the formation of orogenital or skin tumors. PV-induced cell proliferation has been related mainly to the expression of two small oncoproteins, E6 and E7. In mammalian PVs, E6 contains two 70-residue zinc-binding repeats, whereas E7 consists of a natively unfolded N-terminal region followed by a zinc-binding domain which folds as an obligate homodimer. Here, we show that both the novel francolin bird PV Francolinus leucoscepus PV type 1 (FlPV-1) and the chaffinch bird PV Fringilla coelebs PV contain unusual E6 and E7 proteins. The avian E7 proteins contain an extended unfolded N terminus and a zinc-binding domain of reduced size, whereas the avian E6 proteins consist of a single zinc-binding domain. A comparable single-domain E6 protein may have existed in a common ancestor of mammalian and avian PVs. Mammalian E6 C-terminal domains are phylogenetically related to those of single-domain avian E6, whereas mammalian E6 N-terminal domains seem to have emerged by duplication and subsequently diverged from the original ancestral domain. In avian and mammalian cells, both FlPV-1 E6 and FlPV-1 E7 were evenly expressed in the cytoplasm and the nucleus. Finally, samples of full-length FlPV-1 E6 and the FlPV-1 E7 C-terminal zinc-binding domain were prepared for biophysical analysis. Both constructs were highly soluble and well folded, according to nuclear magnetic resonance spectroscopy measurements.

[Importance of immunohistochemical studies in the diagnosis and the prognostic evaluation of cervical intraepithelial neoplasia and invasive squamous cell carcinoma of the uterine cervix. Review]

Immunohistochemical studies in cervical intraepithelial neoplasia and cervical carcinoma are evaluated in this review. A variety of proteins like p53, bcl2, C-Myc, Ki 67, Cyclines, P16 INK4a, p21, p27, beta-catenin, Wnt and MCM, have been related to the development of cervical neoplasia and human papilloma virus infection. It is described how transcriptional factors of genes induce loss of heterozygosity, numerical chromosome abnormality and inactivation of gene products or the partial loss of some membrane glycoproteins induced by oncogenic human papillomaviruses (HPV).

Variant haplotypes at XRCC1 and risk of oral leukoplakia in HPV non-infected samples

BACKGROUND

One of the mechanisms in human papillomavirus (HPV)-related carcinogenesis is inhibition of DNA repair by HPV oncoprotein. In this study, we investigated whether polymorphisms at XRCC1, one of the DNA repair loci, could modulate the risk of tobacco-related leukoplakia and cancer in HPV-infected individuals.

METHODS

Tissue DNA from 83 oral cancer, 91 leukoplakia and 100 healthy controls were screened for HPV 16/18 infection and polymorphisms at XRCC1 by PCR-RFLP to estimate the risk of diseases independently and jointly.

RESULTS

Human papillomavirus infection was significantly associated with increased risk of leukoplakia and cancer (OR = 2.8, 95% CI = 1.2-6.5 and OR = 5.5, 95% CI = 1.6-19, respectively). Independently, genotypes at three polymorphic sites on XRCC1 did not modulate the risk of diseases but pooled variant haplotypes increased the risk of leukoplakia in overall and HPV non-infected (OR = 1.8, 95% CI = 1.2-2.8; OR = 2.2, 95% CI = 1.2-4.0, respectively) samples but not that of cancer.

CONCLUSION

The association between variant haplotypes at XRCC1 and risk of leukoplakia is pronounced in non-infected individuals since HPV oncoprotein could inhibit directly the DNA repair activity of XRCC1. But more samples of leukoplakia and cancer are essential to validate these results.

Prognostic relevance of human papillomavirus L1 capsid protein detection within mild and moderate dysplastic lesions of the cervix uteri in combination with p16 biomarker

OBJECTIVE

To proof the prognostic relevance of HPV L1 capsid protein detection on colposcopically-guided punch biopsies in combination with p16.

STUDY DESIGN

Sections of colposcopically-guided punch biopsies from 191 consecutive cases with at least 5 years of follow-up were stained with HPV L1 capsid protein antibodies (Cytoactiv screening antibody) and a monoclonal anti-p16 antibody. Fifty sections were derived from a benign group, 91 from low-grade (cervical intraepithelial neoplasia [CIN 1]) lesions and 50 from high-grade (CIN 2 and 3) lesions.

RESULTS

Overall only 16.1% of the 87 L1-negative, p16-positive CIN lesions showed remission of the lesion compared to 72.4% of the double positive cases. None of the L1/p16 double negative CIN lesions progressed.

CONCLUSION

HPV L1 capsid protein detection with Cytoactiv screening antibody seems to be a promising new tool to predict the behavior of HPV-associated (p16-positive) early dysplastic lesions.

Early detection of cervical neoplasia by Raman spectroscopy

Early detection of malignant tumours, or their precursor lesions, improves patient outcome. High risk human papillomavirus (HPV), particularly HPV16, infection can lead to the development of uterine cervical neoplasia, and therefore, the identification in clinical samples of the effects of HPV infection may have clinical value. In this report, we apply Raman microspectroscopy to live and fixed cultured cells to discriminate between defined cell types. Raman spectra were acquired from primary human keratinocytes (PHK), PHK expressing the E7 gene of HPV 16 (PHK E7) and CaSki cells, an HPV16-containing cervical carcinoma-derived cell line. Averaged Raman spectra showed variations, mostly in peaks originating from DNA and proteins, consistent with HPV gene expression and cellular changes associated with neoplasia, in both live and fixed cells. Principal component analysis produced good discrimination between the cell types, with sensitivities of up to 100% for the comparison of fixed PHK and CaSki. These results demonstrate the ability of Raman spectroscopy to discriminate between cell types representing different stages of cervical neoplasia. More specifically, this technique was able to identify cells expressing the HPV 16 E7 gene accurately and objectively, suggesting that this approach may be of value in diagnosis. Moreover, the ability to detect the effects of the virus in fixed samples also demonstrates the compatibility of Raman spectroscopy with current cervical screening methods. (c) 2007 Wiley-Liss, Inc.

Myc and human papillomavirus type 16 E7 genes cooperate to immortalize human keratinocytes

The E6 protein of the oncogenic human papillomaviruses (HPVs), in combination with the E7 protein, is essential for the efficient immortalization of human foreskin keratinocytes (HFKs). Since we recently demonstrated that E6 activates the human telomerase reverse transcriptase (hTERT) promoter via a Myc-dependent mechanism, we speculated that overexpressed Myc might be able to substitute for E6 in cell immortalization. Myc (similar to E6) was unable to immortalize HFKs when transduced alone, despite inducing high levels of telomerase activity. However, when transduced with E7, Myc immortalized HFKs following a brief but detectable crisis period. In contrast to E6 + E7-immortalized cells, the Myc + E7-immortalized cells expressed high levels of p53 protein as well as two p53-regulated proteins, p21 and hdm-2. The increase in p21 and hdm-2 proteins correlated directly with their mRNA levels, suggesting transcriptional activation of the respective genes by the overexpressed p53 protein. Interestingly, a significant proportion of the p53 protein in the Myc + E7-immortalized cells was localized to the cytoplasm, potentially due to interactions with the overexpressed hdm-2 protein. Regardless, cell immortalization by the Myc + E7 genes occurred independently of p53 degradation. Since we have already observed high-efficiency cell immortalization with the hTERT + E7 or E6 mutant (p53 degradation-defective) + E7 genes (i.e., no crisis period) that proceeds in the presence of high levels of p53, we hypothesize that the crisis period in the Myc + E7 cells is due not to the levels of the p53 protein but rather to unique properties of the Myc protein. The common factor in cell immortalization by the three gene sets (E6 + E7, Myc + E7, and hTERT + E7 genes) is the induction of telomerase activity.

Inhibition of T-cell receptor signal transduction and viral expression by the linker for activation of T cells-interacting p12(I) protein of human T-cell leukemia/lymphoma virus type 1

The p12(I) protein of human T-cell leukemia/lymphoma virus type 1 (HTLV-1) is a small oncoprotein that increases calcium release following protein kinase C activation by phorbol myristate acetate, and importantly, this effect is linker for activation of T cells (LAT) independent. Here, we demonstrate that p12(I) inhibits the phosphorylation of LAT, Vav, and phospholipase C-gamma 1 and decreases NFAT (nuclear factor of activated T cells) activation upon engagement of the T-cell receptor (TCR) with anti-CD3 antibody. Furthermore, we demonstrate that p12(I) localizes to membrane lipid rafts and, upon engagement of the TCR, relocalizes to the interface between T cells and antigen-presenting cells, defined as the immunological synapse. A p12(I) knockout molecular clone of HTLV-1 expresses more virus upon antigen stimulation than the isogenic wild type, suggesting that, by decreasing T-cell responsiveness, p12(I) curtails viral expression. Thus, p12(I) has contrasting effects on TCR signaling: it down-regulates TCR in a LAT-dependent manner on one hand, and on the other, it increases calcium release in a LAT-independent manner. The negative regulation of T-cell activation by p12(I) may have evolved to minimize immune recognition of infected CD4(+) T cells, to impair the function of infected cytotoxic CD8(+) T cells, and to favor viral persistence in the infected host.

[Progress of study on anti-human cervical papilloma virus infection with Chinese and Western medicine]

Human papilloma virus (HPV) infection is closely correlated with the occurrence of cervical cancer and precancerous lesion, high risk HPV can induce cervical cancer by the corresponding protein of E6 and E7 gene expression. Earlier diagnosis and earlier prevention of HPV infection are the key points in blocking cervical cancer, and combined use of Chinese herbal preparations with Western medicine is the important way for preventing HPV infection and prohibiting cervical canceration. So, to develop anti-viral chemical compound from natural drugs has become the hotspot of research today.

Circulating human papillomavirus type 16 specific T-cells are associated with HLA Class I expression on tumor cells, but not related to the amount of viral oncogene transcripts

Human papillomavirus (HPV) is a necessary factor in the pathogenesis of cervical cancer. Circulating HPV-specific T-cells responding to the E6 and E7 HPV proteins can be detected only in half of cervical cancer patients. Potential explanations for the absence of this response are lack of sufficient amounts of antigen to activate the immune response or local immune escape mechanisms. We studied the relationship between HPV 16 E6/E7 oncogene mRNA expression, human leukocyte antigen (HLA) expression on tumor cells and the presence of circulating E6- and E7-specific T-cell responses in cervical cancer patients. The amount of antigen was assessed by HPV E6/E7 mRNA expression levels measured by quantitative polymerase chain reaction. HLA Class I and Class II expression on tumor cells was analyzed by immunohistochemistry. A proliferative HPV-specific T-cell response was detected in 15/29 patients. The amount of HPV E6/E7 mRNA was not related to the presence of immune response. HLA Class I expression was downregulated in 19 patients and completely lost in 7 patients. HLA Class II expression was upregulated in 18 patients. HLA Class I expression on tumor cells showed a strong correlation with immunity (p = 0.001). Explicitly, all patients with complete HLA loss lacked HPV specific T-cell responses. The presence of circulating HPV-specific T-cells might reflect ongoing antitumor response that is sustained by CD8+ T-cells killing HLA Class I positive cancer cells. We hypothesize that HLA Class I expression status on tumor cells might as well influence the response to HPV E6/E7 directed immunotherapy.

Relationship between HPV16/18 E6 and 53, 21WAF1, MDM2, Ki67 and cyclin D1 expression in esophageal squamous cell carcinoma: comparative study by using tissue microarray technology

AIM

To investigate the role of human papillomavirus (HPV) HPV16/18 E6 oncogene in the carcinogenesis of esophageal cell carcinoma (ESCC).

MATERIALS AND METHODS

Tissue microarray (TMA) block was constructed from 60 cases of paraffin-embedded ESCC tissues and pair-matched controls (adjacent normal epithelium). Immunohistochemistry (IHC) methods were applied to detect the expression of HPV16/18 E6, p53, p21(WAF1), MDM2, Ki67 and cyclin D1 proteins on TMA slides. In situ hybridization (ISH) targeting HPV gene was also used.

RESULTS

In ESCC samples, 18.3% (11/60) were revealed HPV16/18 E6 positive by IHC, while 40.0% (24/60) HPV positive by ISH; HPV16/18 E6 expression was significantly higher than that of control samples. In ESCC samples, the expressions of p53, p21(WAF1), Cyclin D1, MDM2 and Ki67 were recorded in 60.0% (36/60), 40.0% (24/60), 51.7% (31/60), 65.0% (39/60) and 88.3% (53/60) cases respectively, In ESCC samples, p53, MDM2 and Ki67 expression correlated with the HPV16/18 E6 expression (p less, similar 0.01), p21(WAF1) expression - with these of MDM2 and cyclin D1 (p less, similar 0.01) whilst expression of Ki67 - with ESCC grade (p less, similar 0.01).

CONCLUSION

HPV might be one of etiological factor of esophageal carcinoma in Shantou, China. p53, MDM2 proteins may play important roles in the pathogenesis of HPV-associated ESCC.

Comparative Analysis of 19 Genital Human Papillomavirus Types with Regard to p53 Degradation, Immortalization, Phylogeny, and Epidemiologic Risk Classification

We have analyzed E6 proteins of 19 papillomaviruses able to infect genital tissue with regard to their ability to degrade p53 and the thus far unknown immortalization potential of the genomes of human papillomaviruses (HPV) 53, 56, 58, 61, 66, and 82 in primary human keratinocytes. E6 proteins of HPV types 16, 18, 33, 35, 39, 45, 51, 52, 56, 58, and 66, defined as high-risk types, were able to induce p53 degradation in vitro, and HPV18-, HPV56-, and HPV58-immortalized keratinocytes revealed markedly reduced levels of p53. In contrast, the E6 proteins of HPV6 and 11 and HPV44, 54, and 61, regarded as possible carcinogenic or low-risk HPV types, respectively, did not degrade p53. Interestingly, the E6 proteins of HPV 53, 70, and 82 inconsistently risk classified in the literature were also found to induce p53 degradation. The genomes of HPV53 and 82 immortalized primary human keratinocytes that revealed almost absent nuclear levels of p53. These data suggest a strict correlation between the biological properties of certain HPV types with conserved nucleotide sequence (phylogeny), which is largely coherent with epidemiologic risk classification. HPV types 16, 18, 33, 35, 39, 45, 51, 52, 56, 58, and 66, generally accepted as high-risk types, behaved in our assays biologically different from HPV types 6, 11, 44, 54, and 61. In contrast, HPV70, regarded as low-risk type, and HPV53 or HPV82, with inconsistent described risk status, were indistinguishable with respect to p53 degradation and immortalization from prototype high-risk HPV types. This could imply that other important functional differences exist between phylogenetically highly related viruses displaying similar biological properties in tissue culture that may affect their carcinogenicity in vivo.

DMBA/TPA-Induced Tumor Formation Is Aggravated in Human Papillomavirus Type 16 E6/E7 Transgenic Mouse Skin

Human papillomavirus type 16 (HPV16) is a major causative factor in the development of uterine cervical carcinomas. We investigated the role of E6/E7 in tumor formation. Skin-specific E6/E7 transgenic mice showed approximately twice as many tumors compared with nontransgenic mice in dimethylbenz[a]anthracene (DMBA)-initiated and a 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted two-stage skin carcinogenesis. This model showed a significant increase of epidermal cell proliferation in the transgenic mice. The 8-hydroxy-2'deoxyguanosine (8OH-dG) detection assay showed that oxidative DNA damage was significantly higher in the transgenic mice after TPA treatments. The overexpression of E6/E7 in the skin in the DMBA/TPA two-stage-induced carcinogenesis model aggravated the incidence of tumor formation. HPV16 E6/E7 appears to act as an enhancer of carcinogenesis that requires initiation by DMBA and promotion by TPA.

Early integration of high copy HPV16 detectable in women with normal and low grade cervical cytology and histology

BACKGROUND

Integration of human papillomavirus (HPV) DNA has been considered a late event in cervical carcinogenesis. However, integrated forms of HPV were recently detected in cancer precursor lesions using a new real time polymerase chain reaction (PCR) to detect the deletions at the 3362-3443 region of HPV16 E2 OBJECTIVE: To study the frequency of HPV16 DNA integration in cervical lesions and compare the sensitivity of an additional upstream region of the E2 ORF (2962-3138) in detecting HPV integration.

METHODS

Using the TaqMan based PCR, HPV16 positive DNA samples were analysed in 164 cervical scrapings from women participating in a multicentre screening trial. Biopsy confirmation was available in 62 cases.

RESULTS

Primers targeting the 3362-3443 region detected the majority of E2 deletions. In only 23% of the samples was the E2 upstream region equal or better target than the 3362-3443 region. Mixed (episomal/integrated) pattern was the most prevalent physical state of HPV16, also present in PAP smears with normal morphology. Pure integrated form was most prevalent in HSIL and cancer lesions, but also detectable in low grade abnormalities (NSIL, ASC-US, LSIL). Women with only integrated HPV16 were almost 10 years older than those with episomal HPV16. Viral load of integrated HPV16 was related to cytological abnormality (p = 0.003) but not to histology.

CONCLUSIONS

Integrated HPV16 is present in low grade cervical lesions, mostly mixed with the episomal form. Women with the pure integrated form of HPV16 are older than those with the other forms.

Factors influencing subcellular localization of the human papillomavirus L2 minor structural protein

Two structural proteins form the capsids of papillomaviruses. The major structural protein L1 is the structural determinant of the capsids and is present in 360 copies arranged in 72 pentamers. The minor structural protein L2 is estimated to be present in twelve copies per capsid. Possible roles for L2 in interaction with cell surface receptors and in virion uptake have been suggested. As previously reported, L2 localizes in subnuclear domains identified as nuclear domain 10 (ND10). As it was demonstrated that L2 is able to recruit viral and cellular proteins to ND10, a possible role for L2 as a mediator in viral assembly has been proposed. In this study, we determined factors influencing the localization of L2 at ND10. Under conditions of moderate L2 expression level and in the absence of heterologous viral components, we observed that, in contrast to previous reports, L2 is mainly distributed homogeneously throughout the nucleus. L2, however, is recruited to ND10 at a higher expression level or in the presence of viral components derived from vaccinia virus or from Semliki Forest virus. We observed that translocation of L2 to ND10 is not a concentration-dependent accumulation but rather seems to be triggered by yet unidentified cellular factors. In contrast to HPV 11 and 16 L2, the HPV 18 L2 protein seems to require L1 for efficient nuclear accumulation.

Detection of cervical abnormalities in a developing country using measurement of Brn-3a in cervical smears

OBJECTIVE

We have previously shown that Brn-3a is elevated in biopsies from women in the United Kingdom with high grade cervical neoplasia, and that it specifically trans-activates the HPV URR in vitro and in vivo. The aim of this study is to establish the relationship of Brn-3a, HPV E6 and pathological diagnosis in cervical smear from women in a developing country with a high prevalence of cervical disease. This is a follow-up of our previous work in which for the first time Brn-3a and E6 levels in cervical smears from women in United Kingdom were shown to correlate with the histological diagnosis of cervical neoplasia and were even better in predicting underlying pre-malignant disease than conventional procedures.

METHOD

Cervical smears from 295 women with cervical abnormalities attending gynecological clinics in Brazil were used to make RNA. The mRNA levels of Brn-3a and HPV E6 were measured and the data obtained were used to establish the relationship between Brn-3a and the histological diagnosis.

RESULTS

The cellular transcription factor Brn-3a was readily measured in cervical smears from the Brazilian population. Its presence was shown to be frequently associated with the expression of HPV E6. The measured level of Brn-3a parallels the severity of the cervical ailment and predicts the pathological categories.

CONCLUSIONS

The ability of Brn-3a to predict for cervical ailments is independent to the geographical characteristics of the population, and hence it could be used routinely as an adjunct to colposcopy and pathological diagnosis in developing and developed countries.

Expression of the high-risk human papillomavirus type 18 and 45 E7 oncoproteins in cervical carcinoma biopsies

E7 proteins are major oncoproteins of high-risk human papillomaviruses (HPVs), which play a key role in cervical carcinogenesis. These proteins have been shown to immortalize primary human cells. Due to the absence of antibodies with suitable sensitivity and specificity, little is known about expression of the E7 oncoproteins in naturally infected tissues. Recently, high-level expression of the E7 protein of HPV-16, the most prevalent oncogenic HPV type, was demonstrated in cervical carcinomas by immunohistochemistry; however, approximately 15 additional high-risk HPV types are known to be associated with cervical carcinoma. It is unknown whether the E7 oncoproteins of HPV-18 and -45, the second and third most prevalent HPV types, are expressed in cervical cancers. Using antibodies against HPV-18 and -45 E7 proteins, it is shown here for the first time that the HPV-18 and -45 E7 proteins can be detected in cervical carcinoma biopsies. Together with anti-HPV-16 E7 antibodies, this could create the possibility of detecting E7 oncoproteins in approximately 80 % of all cervical cancers.

Value and feasibility of HPV DNA test in cervical scraping smears

To investigate the reliability and feasibility of human papillomavirus (HPV) DNA test in cervical scraping smears with polymerase chain reaction (PCR), 131 cases of cervical scraping specimens were collected, and the positive rates and accuracy of HPV infection were determined in normal subjects and cervical cancer patients. GP5+/GP6+ and E7 primer pairs designed for detecting HPV L1 and HPV type 16 E7 were tested in this study. Our results showed that positive rates of HPV DNA in normal population and cervical cancer patients were 32.99% and 73.53% respectively and there was significant difference between them (P < 0.001). In normal subjects, detection rates of HPV DNA with GP5+/GP6+ and E7 primer pairs were 27.84% and 16.49% respectively, with statistically significant difference between them (P > 0.05). However the detection rates in cervical cancer patients were 38.24% and 67.65% for the two markers, with a significant difference found between them (P < 0.05). It is concluded that HPV DNA test with PCR for cervical scraping smears was feasible. GP5+/GP6+ primer pairs may be a useful probe to screen HPV infection in normal population, but they are not sensitive enough in cervical cancer patients. It is suggested that high risk type HPV DNA test was very useful in population with high risk of cervical cancer.

[The prevalence of E6/E7 HPV type 16 in laryngeal cancer and in normal mucosa]

Many authors suggest that HPV infection can play a great role in development of benign and malignant tumours of upper respiratory tract in human. The aim of this study was to determine the prevalence of E6/E7 HPV-16 in laryngeal squamous cell carcinoma, and normal laryngeal mucosa, and to analyse their correlation with sex, lymph node status, primary tumor stage, localization, and histological differentiation. HPV 16 DNA presence was analysed using PCR technique in 72 samples of laryngeal carcinoma and in samples of 50 normal mucosa. Human papillomavirus was detected in 26 (36.1%) of the 72 patients. There was no statistically significant correlation HPV positivity and clinicopathological features of the analysed group. In 5 (10%) of 50 samples of normal mucosal. HPV 16 presence in normal mucosa and in laryngeal squamous cell carcinoma was detected in 3 patients. Our observations suggest that HPV16 can play a role in pathogenesis of laryngeal cancer.

Does HPV play a role in the etiopathogenesis of ameloblastoma? An immunohistochemical, in situ hybridization and polymerase chain reaction study of 18 cases using laser capture microdissection

Ameloblastomas are epithelial tumors of odontogenic origin, biologically characterized by local recurrence. Among different etiologic factors, HPV infection has been recently postulated to be somehow involved in ameloblastoma etiopathogenesis. To address this issue, we studied 18 ameloblastomas by means of immunohistochemistry, in situ hybridization (conventional and amplified), polymerase chain reaction and nested-polymerase chain reaction analyses using laser capture microdissection in order to detect the occurrence of HPV in this setting. No evidence of HPV infection was detected by morphological examination, immunohistochemistry, in situ hybridization and conventional polymerase chain reaction, while nested-polymerase chain reaction showed a weak positive band in two cases. However, the subsequent restriction enzyme analysis carried out from the nested-polymerase chain reaction amplification products of these two samples excluded the presence of HPV subtypes 16, 18, 31, 33, 35, 52, and 58. The search for HPV 6 and 11 in the same specimens was also negative. In conclusion, our data do not support an etiopathogenetic evidence for HPV in ameloblastoma.

[Detection of high-risk human papillomavirus (HPV) E6 and E7 oncogene transcripts increases the specificity of the detection of a cervical intraepithelial neoplasia (CIN)]

AIMS

The oncogenic potential of the high-risk human papillomavirus (HR-HPV) genotypes depends on the expression of the viral oncogenes E6 and E7. Thus, the detection of these transcripts could serve as a factor in the evaluation of a woman's risk of development of cervical intraepithelial neoplasia (CIN).

METHODS

A nested RT-PCR assay for the detection of E6/E7 oncogene transcripts of all known HR-HPV genotypes was established. Cervical scrapes of 779 HR-HPV-DNA-positive women exhibiting all grades of CIN were examined.

RESULTS

Spliced E6/E7 oncogene transcripts of all the HR-HPVs were detected in numerous samples. In 459 cases with agreement between the cytologic and histologic findings, the prevalence increased with lesion severity: CIN 0, 18%; CIN I, 58%; CIN II, 77%; CIN III, 84%. While sensitivity and negative predictive value of HR-HPV DNA-positivity for the detection of a CIN lesion were significantly (p < 0.0001) higher than those of E6/E7 mRNA positivity (90.3% vs. 65.5% and 93% vs. 83.1%), the opposite was true for the specificity and positive predictive value (72.8 % vs. 95.2%) and 65.1% vs. 88.5%, p < 0.0001). Preliminary follow-up data in 120 initially HPV-16 DNA-positive women revealed the development, persistence or progression of a CIN lesion in 33% (8/24) of HR-HPV DNA-positive and E6/E7 mRNA-negative women, compared to 93% (66/71, p < 0.0001) in women in whom transcriptional activity of the E6/E7 oncogenes was detectable.

CONCLUSIONS

Besides the identification of HPV DNA, the detection of HR-HPV E6/E7 oncogene transcripts may serve as a valuable tool in increasing the specificity of HPV testing.

Cervical human papillomavirus screening by PCR: advantages of targeting the E6/E7 region

PCR is a promising method for detection of human papillomavirus (HPV), the high-risk forms of which are responsible for cervical cancer. PCR primers that target the L1 or E1 region can be unreliable and may miss more advanced disease, whereas those directed at the E6 or E7 regions, which encode oncogenic products, are preferable because 1) the LI/E1 regions, but never the E6/E7 regions, are lost during integration of viral DNA into host genomic DNA, a process that can represent an integral component of progression from infection to tumorigenesis; and 2) the E6/E7 nucleotide sequence exhibits less nucleotide variation. The choice of region used for PCR has implications for HPV screening strategies in the clinical diagnosis and management of cervical cancer.