Papilomavirus humano en pacientes con cáncer cervicouterino: en el Instituto Nacional de Cancerología / Human papilloma virus in patients with neoplasm cervix uterine in the Instituto Nacional de Cancerologia

La utilización de técnicas de ingeniería genética y biología molecular ha permitido aislar e identificar diferentes tipos virales asociados a diversas enfermedades. Tal es el caso del papilomavirus humano (PVH) al cual se ha mencionado como el candidato etiológico del cáncer cervicouterino (CaCu). En el presente trabajo se analizó la presencia de PVH tipos 6, 11, 16 y 18 en ADN de tejido obtenido en biopsias de un grupo de 70 pacientes del Instituto Nacional de Cancerología (INCan), con diagnóstico histológico de CaCu invasor. Mediante hibridación Southern-blot, se observó que 17 (24.3 por ciento) casos fueron positivos para secuencias de PVH 16 y en siete (10 por ciento) para PVH 18; en estas muestras no fueron detectadas secuencias para PVH 6 y 11. Los resultados obtenidos sugieren que los PVH 16 y 18 son poco frecuentes en nuestra población hospitalaria. Es necesario realizar estudios con otros tipos virales asociados a CaCu, como los tipos 31, 33 y 35, a fin de ampliar el espectro de detección de PVH. También es necesario continuar con la identificación de PVH con otras técnicas de biología molecular --como la reacciónde polimesasa en cadena-- para conocer mejor la distribución, la frecuencia y el tipo de infección de PVH en pacientes que acuden al INCan con CaCu.

Detección de ADN de papilomavirus humano en lesiones orales y en tejido oral normal / Presence of DNA in human papilloma virus oral lesions, normal oral tissue

En este trabajo se reporta la presencia de ADN del papilomavirus humano (PVH) tipos 6, 11, 16 y 18 (frecuentes en lesiones genitales) en lesiones premalignas (10 eritroplasias y 11 leucoplasias), malignas (10 carcinomas) y en 10 muestras de tejido oral normal. La identificación de las secuencias de ADN se realizó por la técnica de hibridización de ácidos nucleicos variante dot blot, utilizando marcaje radioactivo, a partir de muestras de biopsia.

The state of the p53 and retinoblastoma genes in human cervical carcinoma cell lines.

Human cervical carcinoma cell lines that were either positive or negative for human papillomavirus (HPV) DNA sequences were analyzed for evidence of mutation of the p53 and retinoblastoma genes. Each of five HPV-positive cervical cancer cell lines expressed normal pRB and low levels of wild-type p53 proteins, which are presumed to be altered in function as a consequence of association with HPV E7 and E6 oncoproteins, respectively. In contrast, mutations were identified in the p53 and RB genes expressed in the C-33A and HT-3 cervical cancer cell lines, which lack HPV DNA sequences. Mutations in the p53 genes mapped to codon 273 and codon 245 in the C33-A and HT-3 cell lines, respectively, located in the highly conserved regions of p53, where mutations appear in a variety of human cancers. Mutations in RB occurred at splice junctions, resulting in in-frame deletions, affecting exons 13 and 20 in the HT-3 and C-33A cell lines, respectively. These mutations resulted in aberrant proteins that were not phosphorylated and were unable to complex with the adenovirus E1A oncoprotein. These results support the hypothesis that the inactivation of the normal functions of the tumor-suppressor proteins pRB and p53 are important steps in human cervical carcinogenesis, either by mutation or from complex formation with the HPV E6 and E7 oncoproteins.

Detection of genital human papillomaviruses by polymerase chain reaction amplification with degenerate nested primers.

Degenerate oligonucleotide primers were designed for in vitro amplification by polymerase chain reaction (PCR) of a relatively well-conserved portion of the L1 capsid protein gene of genital human papillomaviruses. A specific 441bp fragment was amplified by PCR from genomic clones and clinical biopsy specimens containing DNA from HPV types 6, 11, 16, 18, 31, and 33, as well as from a number of other clinical specimens known to contain unclassified HPV isolates. As some HPV non-specific DNA was also often amplified, another set of degenerate primers was designed which amplified a 335 bp sequence contained within the 441 bp sequence. These nested primers could be used in a two-stage PCR reaction to obtain distinct HPV-specific DNA fragments suitable for direct sequencing. Two-stage PCR was used to demonstrate the presence of HPV DNA in 13 out of 16 biopsies, which had been classified histologically as cervical intraepithelial neoplasia (CIN), but which were negative for HPV on Southern blot hybridization. Seven of these amplification products were sequenced, and one proved to be a previously unsequenced HPV type. The results have important implications for the routine detection and typing of genital and other HPV types in clinical samples.

Association of human papillomavirus types 16 and 18 E6 proteins with p53.

Human papillomavirus type 16 (HPV-16) is a DNA tumor virus that is associated with human anogenital cancers and encodes two transforming proteins, E6 and E7. The E7 protein has been shown to bind to the retinoblastoma tumor suppressor gene product, pRB. This study shows that the E6 protein of HPV-16 is capable of binding to the cellular p53 protein. The ability of the E6 proteins from different human papillomaviruses to form complexes with p53 was assayed and found to correlate with the in vivo clinical behavior and the in vitro transforming activity of these different papillomaviruses. The wild-type p53 protein has tumor suppressor properties and has also been found in association with large T antigen and the E1B 55-kilodalton protein in cells transformed by SV40 and by adenovirus type 5, respectively, providing further evidence that the human papillomaviruses, the adenoviruses, and SV40 may effect similar cellular pathways in transformation.

Mapping of linear epitopes of human papillomavirus type 16: the L1 and L2 open reading frames.

Certain types of human papillomavirus (HPV), notably HPV type 16, are associated with flat or inverted proliferative lesions of the cervix uteri that can progress to malignancy. As a first step towards the serological study of the epidemiology of HPV, we have synthesized the entire amino acid sequences of the 2 major viral capsid proteins of HPV type 16, L1 and L2, as a set of 66 synthetic 20-residue peptides with an overlap of 5 amino acids. The peptides were tested for reactivity with IgA, IgG and IgM antibodies in the sera of 30 patients with HPV-16-carrying cervical neoplasms. Both IgG and IgM antibody responses were detected, but most of the reactivity found was of the IgA class. The most immunoreactive peptides were further analyzed for reactivity with sera from 22 patients with parotid gland tumors and with sera from 38 healthy individuals. The L2-encoded protein contained only one major linear epitope, which was not specific for HPV-16-carrying neoplasms. In contrast, the L1-encoded protein contained several epitopes that were regularly immunoreactive with antibodies present in the sera of patients with HPV-16-carrying cervical neoplasms, but only rarely so in the sera of patients with other tumors or of healthy individuals.

Human papillomavirus types and recurrent cervical warts.

We analyzed cervical intraepithelial neoplasias (CINs) detected after cryotherapy to determine if recurrence is associated with the same human papillomavirus (HPV) type found in the original lesion. Eight women had detectable HPV DNA in CINs that occurred after ablation of another CIN, and for each patient the HPV type in the pretreatment lesion was different from that in the CIN that appeared after cryotherapy. This compares with 12 women who had HPV detected in two or more CINs present at the same time, 11 of whom had the same HPV type noted. We concluded that although multiple, simultaneous CINs in a woman often contain the same HPV type, recurrent CINs that occur after cryotherapy contain an HPV type different from that present in the pretreatment lesion.

Enhanced chemiluminescence for tissue antigen and cellular viral DNA detection.

The ability to use enhanced chemiluminescence (ECL) to detect horseradish peroxidase as a label for tissue antigens and cellular viral DNA was demonstrated. A liquid nitrogen-cooled charged-coupled device (CCD) was used to detect light output, which was visualized on a monitor or was quantitated using an attached microcomputer. In a tissue antigen model, equivalent sensitivity was observed between ECL and colorimetric detection.

Evaluación diagnóstica de infecciones de cuello uterino asociadas a infección por virus papiloma humano / Diagnostic evaluation of cervix uteri infections associated with infection caused by human papilloma virus

El objetivo de este trabajo es demostrar la presencia de proteínas de virus papilomas humano (HPV) en biopsias de cuello uterino diagnosticadas histológicamente como cervicopatías de origen viral. Se escogieron 38 biopsias cervicales que cumplían con los criterios mencionados por Toki y Yajima para diagnóstico de HPV. Las biopsias provienen de archivos de placas del programa de detección de cáncer cérvico-uterino de las áreas Norte y Oriente de Santiago. Se empleó la técnica de inmunoperoxidasa usando el método ABC (complejo avidina-biotina-peroxidasa), utilizando como anticuerpo primario, uno policlonal diluido a 1:200, que reacciona con todas las variedades de virus papiloma. Veinte de las 38 biopsias (52,9%) presentan antígenos virales en núcleo de las capas superficiales del epitelio escamoso, en cantidad suficiente como para ser reconocidos por la sensibilidad del método. Este porcentaje es comparable a lo descrito en la literatura y que varía entre un 40% y un 62%

Comparison of Cytobrush and cervicovaginal lavage sampling methods for the detection of genital human papillomavirus.

The development of an accurate method for the detection and typing of genital human papillomavirus is of substantial clinical importance. This virus has been implicated as an etiologic agent in the development of cervical neoplasia. To detect human papillomavirus infection with maximum sensitivity, cells must be collected and assayed for human papillomavirus deoxyribonucleic acid. We compared two noninvasive methods of sampling exfoliated cervical cells--cervicovaginal lavage and scrape-Cytobrush. Seventy-four patients newly referred to the colposcopy clinic were divided randomly for cell sampling by either cervicovaginal lavage followed by scrape-Cytobrush or, conversely, scrape-Cytobrush followed by cervicovaginal lavage. Restriction analysis and Southern blot hybridization were used to test all the samples thus obtained for human papillomavirus. Overall, test results from 42 patients (56.8%) were positive for human papillomavirus deoxyribonucleic acid. Twenty-six (31.1%) tested positive for human papillomavirus by both sampling methods, and 32 (43.2%) tested negative for human papillomavirus by both methods. One (1.4%) tested positive with scrape-Cytobrush sampling but negative with cervicovaginal lavage, while 15 (20.3%) tested negative with scrape-Cytobrush but positive with cervicovaginal lavage (p less than 0.001, McNemar's test). These data, combined with previous work from our group, suggest that, of the available methods, cervicovaginal lavage, coupled with human papillomavirus deoxyribonucleic acid hybridization, is the most sensitive noninvasive method for harvesting cells for molecular identification of human papillomavirus in the female lower genital tract.

DNA dot-blot hybridization implicates human papillomavirus type 11-DNA in epithelioma cuniculatum.

Epithelioma cuniculatum is a rare, low-grade squamous cell carcinoma, belonging to the group of verrucous carcinomas. Evidence is presented that suggests that human papilloma virus type-11 may be involved in the pathogenesis of epithelioma cuniculatum. HPV-DNA was detected by dot-blot hybridization with 32P-labelled probe DNA. Plasmids containing HPV-DNA were isolated by the benzoylated naphthoylated DEAE cellulose method (BND-method), an improved procedure for routine detection of HPV-DNA.

In situ hybridization analysis of human papillomavirus in anal squamous cell carcinoma.

To investigate the association between human papillomavirus (HPV) infection and anal carcinoma, we applied a sensitive in situ hybridization technique to detect HPV messenger RNA (HPV m-RNA) in formalin-fixed, paraffin-embedded sections from 18 patients. Using tritium-labeled probes, HPV m-RNA was detected in 12/18 (67%) patients. HPV 6 was detected in four patients, coexisting with HPV 18 in two cases, and HPV 16 was found in eight patients. In six patients, hybridization failed to demonstrate the presence of HPV. With respect to histology, HPV 6 was detected in 1/4 cases of well differentiated invasive squamous cell carcinoma. Ten of thirteen moderately or poorly differentiated invasive squamous cell carcinomas demonstrated HPV m-RNA (HPV 16, eight cases; HPV 6, one case; HPV 6 and 18, one case). HPV 31 was not detected in any specimens. These results suggest that HPV infection may play an important role in the pathogenesis of anal carcinoma.

Sensitive detection of nucleic acids and protein of human papillomavirus type 6 in respiratory and genital tract papillomata.

We have developed a sensitive method to detect and localize HPV-6 viral DNA, mRNA and protein in biopsy specimens of genital and respiratory tract lesions by using in situ hybridization and immunoperoxidase assays on sections of plastic-embedded tissue. This modified in situ hybridization technique, using ultrathin sections and strand-specific 3H-labelled riboprobes, offers the advantages of superior morphological preservation and detection of viral genomes at low copy number with good resolution. This modified immunocytochemistry provides better sensitivity when compared to previous methods using paraffin-embedded materials. In respiratory tract lesions, immunoperoxidase assay detected only a few capsid antigen positive cells, while in the genital tract lesions, there were more capsid antigen positive cells. Southern transfer analyses and in situ hybridizations demonstrated the presence of more viral nucleic acids in genital tract papillomata than respiratory tract papillomata. Epithelial cells throughout the papillomata were infected by HPV-6 as evidenced by positive hybridization, with more viral DNA present in superficial cells. Our results suggest that genital tract epithelium is more permissive for HPV-6 replication than respiratory tract epithelium. Using stand-specific probes synthesized from subgenomic fragments of the HPV-6 genome in conjunction with nuclease digestions, we were able to demonstrate that HPV-6 transcripts specific to open reading frames (ORFs) E6, E7, E1, L1, and L2 occur in maturing superficial cells. In contrast, transcripts specific to ORFs E1, E2, E4, E5a, and E5b could be detected throughout the whole of the epithelium with more signals noted at the basal cell areas. In addition, the distribution of HPV-6 nucleic acids and protein in a carcinoma in situ of the larynx was analyzed. In comparison to benign respiratory tract papillomata, more viral DNA was found in the malignant lesion, but the pattern and distribution of transcription and capsid antigen was similar.

Molecular characteristics and physical state of human papillomavirus DNA change with progressing malignancy: studies in a patient with epidermodysplasia verruciformis.

In order to establish the role of human papillomavirus (HPV) in carcinogenesis of epidermodysplasia verruciformis (EV), the presence, the molecular characteristics and the physical state of HPV DNA in a benign lesion, a primary carcinoma and a metastatic carcinoma developing in the same EV patient were studied and compared. Of the 2 HPV DNAs isolated from benign macular lesions, only one (a subtype of HPV 5) was detected in both primary and metastatic tumors. Only one normal species of viral DNA molecule was detected in the benign lesion, whereas most, if not all, viral DNA molecules present in the carcinoma (both primary and metastatic) were aberrant ones. The major viral DNA molecule in the primary carcinoma was a large HPV DNA with duplicated 40% subgenomic segments, and was present as free episomes. The major viral DNA molecule in the metastatic carcinoma was the 40% subgenomic segment itself, lacking the remaining 60% segment of the viral genome, and was integrated within cellular DNA. Thus, HPV DNA was present in tumors at any stage of malignancy, and its molecular characteristics and physical state changed not only with the development but also with the enhancement of malignancy, consistently conserving its defined 40% subgenomic segment as the predominant viral sequences. Our results suggest that HPV 5 may be actually involved in carcinogenesis in EV patients.

Demonstration of in vitro synthesis of human papilloma viral proteins from hand and foot warts.

HPV particles purified from [35S]-methionine labeled and unlabeled halves of single hand and foot warts have been fractionated into empty, light full, and heavy full particles by buoyant density gradient centrifugation, and their proteins analyzed by two-dimensional gel electrophoresis (IEF and NEPHGE) and visualized by either fluorography or silver staining. The L1 coat protein (54 Kd) was found in trace amounts in unmodified and slightly modified forms in the labeled empty and light full particles but could not be detected in the labeled heavy particles. L1 appeared to exist in the three unlabeled particle types in differentially modified forms. A putative L2 protein was also found to be modified (74-80 Kd) and was found preferentially in the unlabeled heavy full particles. The commercial cross-reactive BPV antibody recognized a labeled 58-Kd protein found predominantly in the empty and light full particles and a pair of proteins (41-42 Kd) found unlabeled in the heavy full particles. Besides L1, there were several other proteins (IEF 40 Kd; NEPHGE 42, 38, and 36 Kd) which were detected labeled in the empty particles and in increasing unlabeled amounts in the light full and heavy full particles. Four proteins (IEF 66, 13 and 11 Kd, and NEPHGE 9 Kd) were found exclusively in the full particles and may be involved in packing the viral genome. These observations suggest that a virus particle assembly pathway exists from the empty particles, via the light full, to the mature heavy full particles.

Filter in situ hybridisation: an evaluation of the FISH technique for HPV detection in cervical swabs.

The filter in situ hybridisation (FISH) method for detection of HPV in cervical swabs was evaluated against the Southern blot technique on concomitant cervical biopsies. Of 73 biopsies, HPV 16 DNA sequences were found in 26 biopsies and HPV 18 sequences in 2 biopsies. Analysis by FISH of the corresponding smears detected 58 and 100% of these, respectively. Of the smears corresponding to the HPV-negative biopsies, 17% were HPV 16-positive and 3% were HPV-18 positive by FISH. Re-hybridisation with cold plasmid added for competition did not change these results. To estimate the risk of spurious hybridisation between vector remnants in the probe and bacterial DNA sequences present in smears, we have hybridised by FISH to preparations of the 19 most common vaginal microorganisms. Of these, E. coli, which is present in about 10% of cervical smears, hybridised strongly with a probe of the plasmid vector pBR322 and may be a significant cause of false positive FISH results. None of the bacteria hybridised with probes of purified HPV when cold, denatured plasmid was added for competition. Analysis by FISH with probes of purified pBR322 to 167 smears of a patient control group resulted in 6% positive reactions. In hybridisations with probes of HPV 16 and 18 to 2 or 3 different filter preparations of the same smear, identical results were obtained in 18 of 19 smears, indicating a good reproducibility by the FISH method. The high percentage of HPV negative smears is equivalent to the rates known from cytology and may reflect sampling errors.

Sandwich hybridization in solution: a rapid method to screen HPV 16 DNA in cervical scrapes.

A solution hybridization method is introduced as a rapid diagnostic method for demonstration of papillomavirus DNA in cervical scrapes. 32P-Labelled detector probe and the biotinylated capture probes were hybridized with DNA of the specimen after pretreatment by boiling in alkaline SDS. After 4 h of hybridization the hybrids were collected onto avidin coated beads and measured. The sensitivity of the method was 1-5 x 10(5) HPV 16 DNA molecules. Cervical carcinoma cell lines CaSki and SiHa were informative as to the sensitivity of the solution hybridization and the in situ hybridization methods. CaSki cells containing about 700 HPV 16 DNA copies per cell were positive by both methods. SiHa cells with one HPV 16 DNA copy per cell were positive by the sandwich assay but remained negative in the in situ test. A series of 126 cervical scrapes collected from consecutive patients participating in a follow-up study for cervical HPV infection were tested for HPV 16 DNA by both methods. The detection rate of the sandwich test was 19/126 (15%) and that of the in situ method 21/126 (17%) yielding 26 diagnoses altogether. Twelve of these were obtained by one method only. The results obtained by studying the cervical cell lines and repeated specimens taken from constantly HPV 16 positive patients suggested that the two methods can measure different types of infections and thus complement each other in the diagnosis of cervical HPV infections.

Warts in fish handlers.

Fish handlers frequently suffer from hand warts. The clinical form and HPV type in these lesions were studied. Eleven individuals (10 fishmongers and one fisherman) with multiple hand warts were examined clinically and samples from their warts examined by Southern blot and reverse blot analysis. Clinically, with one exception, the warts were of the common type. HPV DNA was detected in all but one individual. HPV4 was found in one sample, HPV1 related virus in three, a virus hybridizing with both HPV27 and HPV2 in five (four individuals) and HPV7 in seven (six individuals). More than one type was detected in four individuals. HPV7 infection was related to the greater length of time spent in handling fish. These findings indicate that HPV7 is not, as was previously thought, found exclusively in those handling butcher meat and suggest that environmental conditions may be a factor in the clinical manifestation of HPV7 infection. The exact nature of a virus designated HPV2/27 and the significance of its presence in these fish handlers remains uncertain.