Evaluation of two commercially available nucleic acid hybridization assays for the detection and typing of human papillomavirus in clinical specimens.

Southern blot (Oncor, Gaithersburg, MD) and dot blot (Life Technologies, Gaithersburg, MD) nucleic acid hybridization assays were compared for their ability to detect and type human papillomavirus (HPV) DNA in 50 cervical swab specimens and 11 biopsy specimens. Overall agreement between the two methods was 78.7%. With the use of Southern blot analysis, HPV 6, 11, 16, or 18 was detected in 22 specimens, however, 4 were untypable because of abnormal or smeared band patterns. Dot blot analysis detected HPV 6/11, 16/18, or 31/33/35 in those same 22 specimens and in 9 additional specimens. Eight of the 13 specimens in which HPV was not detected or untypable by Southern blot contained type 31/33/35 by dot blot. Based on convenience of specimen collection and transport, ease of performance and the ability to detect HPV types 31, 33, and 35, the authors are currently using the dot blot assay for the detection and typing of HPV in clinical specimens.     

Optimization of human papillomavirus genotype detection in cervical scrapes by a modified filter in situ hybridization test.

Optimal conditions for the screening of cervical scrapes for human papillomavirus (HPV) were investigated by using filter in situ hybridization. Since integrated and episomal HPV can be found, cell lines containing viral DNA in an integrated form (HPV in CaSki) or in an episomal state (BK virus-induced hamster tumor cells) were used for optimization experiments. An increase in sensitivity was achieved by alkaline denaturation and neutralization before the specimens were spotted onto the membrane. This increase was 5-fold for the episomal virus and 16-fold for the integrated virus in the model system, as compared with other methods. To evaluate this method on clinical material, 1,963 cervical scrapes were screened for the presence of HPV 6/11 and HPV 16. Nineteen scrapes were positive for HPV 6/11 or HPV 16; and in 1,810 scrapes, no HPV 6/11 or HPV 16 could be detected by the modified filter in situ hybridization technique. Scrapes from which the interpretation of the modified filter in situ hybridization results were equivocal (n = 71, 3.6%) or in which positivity was detected for both HPV 6/11 and HPV 16 (n = 63, 3.2%) were further analyzed by the DNA dot spot technique. Eight scrapes with an equivocal result and only one scrape showing a double positivity by the modified filter in situ hybridization technique could be confirmed in the dot spot assay. In the total group 12 scrapes were positive for HPV 6/11 DNA, 15 were positive for HPV 16 DNA, and 1 was positive for both HPV 6/11 and HPV 16 DNA. Southern blot analysis on modified filter in situ hybridization-positive and -negative scrapes revealed a 100% correlation.     

Comparison of Southern blot hybridization and polymerase chain reaction methods for the detection of human papillomavirus DNA.

A methodologic study was performed to compare the polymerase chain reaction (PCR) and Southern blot hybridization, two commonly used testing strategies for the detection of human papillomavirus (HPV) infection. Three laboratories tested masked aliquots of exfoliated cervical cell specimens obtained from 120 women by cervicovaginal lavage. The study population included 32 women with condylomatous atypia or cervical intraepithelial neoplasia and 88 control women with no known history of cervical neoplasia. Two laboratories used PCR with different sets of consensus primers for HPV detection. The third laboratory used low-stringency Southern blot hybridization to identify all HPV types, followed by high-stringency Southern and/or dot blot hybridization to confirm specific HPV types. One of the PCR primer sets detected HPV types with a differential efficiency that was not predicted by analysis of DNA sequences or direct testing of HPV-containing plasmids. In contrast, the second PCR primer set was shown to be a much broader consensus system, detecting the same HPV types as Southern blotting, though requiring much less clinical specimen. Over 80% of women with cervical intraepithelial neoplasia or condylomatous atypia were found to be HPV infected both by Southern blotting and by the second PCR primer set. Among the control women, 11% were HPV positive by Southern blotting, while 31% were positive with the second set of primers. Most of the HPV infections found only by PCR were not due to HPV type 6, 11, 16, 18, 31, 33, or 45. These known HPV types were uncommon among normal women in the study population, even as determined by the PCR method.     

Detection of specific types of human papillomavirus in cervical scrapes, anal scrapes, and anogenital biopsies by DNA hybridization

Specific varieties of human papillomavirus (HPV) infecting the anogenital region were detected in clinical samples by use of a filter hybridization technique suitable for rapid screening of cervical and anal scrapes. In this way possibly benign types (HPV6 and HPV11) could be differentiated from types thought to be capable of malignant transformation (HPV 16 and HPV 18). Cervical or anal canal cells were applied directly to nylon filters and fixed by u.v. irradiation before hybridization with mixed viral DNA probes under both low- and high-stringency conditions. In addition, probe for the human Alu-repeated DNA sequence was used to assess the relative amount of total nucleic acids in each sample applied to the filter. HPV DNA was detected in 3 of 19 cervical scrapes from patients with no past or present history of wart virus infection or cervical dysplasia. Within a positive study group totalling 71 patients, HPV (6/11 or 16/18) was detected in cervical scrapes from 24% of 41 patients who did not have visible genital dysplasia, 30% of 27 patients with visible genital dysplasia or cervical intraepithelial neoplasia (CIN) I, and in 1 of 3 patients with past CIN II/III. In addition, HPV6/11 or 16/18 DNA was detected in anal scrapes from 3 of 6 male patients and in 85% of genital biopsies. A notably high proportion (4/6) of vaginal condylomata were positive with both the HPV6/11 and the HPV16/18 mixed viral DNA probes. Of the biopsies prepared for histopathology and positive for HPV DNA, the HPV group-specific antigen could be detected in only 60%.     

Genital human papilloma virus infection in Oslo studied by dot blot DNA hybridization and the polymerase chain reaction.

Samples from patients with genital condyloma acuminata or with cervical condylomas and/or dysplasia and from women without cytological/clinical evidence of cervical affection were examined by dot blot DNA hybridization or the polymerase chain reaction (PCR). The PCR was much more sensitive than dot blot, more than doubling the human papilloma virus (HPV) findings. HPV DNA, mainly HPV 6/11, was detected in 18 of 19 biopsies of condyloma acuminata, whereas HPV 16 was most frequently detected in the 21 cervices (76%) with condyloma and/or dysplasia. HPV 16 was detected in eight of 103 cervical smears with no signs of infection. The prevalence of HPV 16 in cervical samples was somewhat higher than expected. This suggests that, in Oslo, HPV 16 is a common HPV type in women with cytologically normal cervices. HPV 18 was relatively rare and was detected only in combination with other HPVs.     

Detection of human papillomavirus DNA by the nucleic acid sandwich hybridization method from cervical scraping

Cervical scrapes collected from 100 consecutive patients participating in a prospective follow-up study for cervical human papillomavirus (HPV) infections were tested for the presence of HPV 11 DNA by the nucleic acid sandwich hybridization method, which allows testing the specimens in a crude form. Part of each specimen was processed through phenol extraction and DNA purification to a dot blot hybridization assay. The dot blots were serially hybridized with HPV 6, 11, 16, and 18 probes as well as with an Alu-repeat probe to estimate the number of cells in the specimen. In PAP smears, HPV-infection was suspected in 63 patients whereas in 37 patients the smear was negative. In the first group, the dot blot assay revealed three cases of HPV 11, two of HPV 16, and one of HPV 18 infection. In the second group with normal PAP smear, one additional HPV 18 infection was found. The sandwich hybridization assay detected 5 HPV 11 infections, including the three mentioned above. All HPV DNA-positive samples contained at least 1.6 X 10(6) cells. Since we considered this a prerequisite for successful diagnosis, only 25 specimens in the first group and 15 in the second were adequate specimens. Thus the HPV-DNA detection rate was 32% (8/25) in the first group and 1/15 in the second. This study demonstrates that sandwich hybridization, detecting 1-3 X 10(5) HPV 11 molecules is a reliable diagnostic method. Cervical scrape is a valuable alternative to punch biopsy, but the number of cells collected is critical for the outcome of the assay.     

Detection of human papillomavirus in skin and genital lesions of renal allograft recipients by in situ hybridization

Renal allograft recipients have an increased incidence of malignancy including squamous carcinoma of cervix and skin. There is growing evidence that human papillomavirus (HPV) has a part to play in malignant transformation at these sites. We have previously identified HPV DNA in the skin and genital lesions of such patients by dot and Southern blotting. In situ hybridization studies, using biotinylated DNA probes for HPV 4, 5 and 8 in skin lesions and 6, 11. 16 and 18 in genital lesions, were performed on tissues derived from the same group of patients. In the cutaneous lesions, only 25% of the specimens probed were found to contain virus by in situ hybridization; 60% of these specimens were found to harbour virus by dot and Southern blotting. In situ hybridization revealed HPV 16 and/or 18 in 86% of the genital lesions probed.     

Detection of human papillomavirus in reprocessed routine Papanicolaou smears by DNA hybridization

DNA dot blot hybridization was used for the detection of human papillomavirus (HPV) types 6, 11, 16, and 18 in reprocessed routinely collected Papanicolaou smears. DNA was extracted from the smears with alkaline lysis and applied onto a nitrocellulose filter. The specificity and sensitivity of the dot blot hybridization on reprocessed Papanicolaou smears were confirmed by Southern blot analysis of selected samples, using CaSki, SiHa cell lines as positive controls and HF 32 as negative controls. From 42 normal smears and 44 abnormal smears with koilocytosis present, 9 (21%) and 43 (98%), respectively, were positive for HPV 6/11/16 or 18. These results show that reprocessed Papanicolaou smears in combination with DNA hybridization have potential application in retrospective studies on the prevalence and distribution of HPV infection.     

Detection and typing of human papillomavirus using the Vira Type "in situ" kit: comparison with a conventional dot blot technique

A new commercial kit (Vira Type "in situ", Life Technologies, Inc., Molecular Diagnostics Division, Guithersburg, Maryland, USA) for the detection of human papillomavirus (HPV) types 6, 11, 16, 18, 31, 33 and 35 in routinely processed human anogenital tissue was compared with a conventional dot blot assay for HPV 6, 11, 16 and 18. Both systems use double-stranded genomic DNA probes for the detection of type specific HPV DNA. The probes used on the dot blots were labelled with 32P and visualised autoradiographically. The Vira Type probes were labelled with biotin and visualised using a streptavidin-alkaline phosphatase conjugate with NBT-BCIP substrate. Biopsy specimens from the cervix, vagina, and vulva of 46 women were processed by both methods and compared. The histological diagnoses ranged from benign changes, to dysplasia, and invasive carcinoma. Overall, 50% of biopsy specimens were positive for HPV DNA by dot blot hybridisation; only 39% were positive by Vira Type in situ hybridisation. Three of the specimens positive by the Vira Type "in situ" kit showed no cross hybridisation and were the same HPV type as the dot blot. A further 13 showed hybridisation, but the showed cross hybridisation, but the to the dot blot results. One biopsy specimen was positive for different HPV types by the two tests and one was positive by Vira Type and negative by dot blot. Six biopsy specimens were negative by Vira Type but positive by dot blot. It is concluded that the Vira Type "in situ" kit has a similar specificity but lower sensitivity than the dot blot hybridisation method for the detection of HPV DNA.     

Diagnostic sensitivity of polymerase chain reaction and Southern blot hybridization for the detection of human papillomavirus DNA in biopsy specimens from cervical lesions.

Human papillomaviruses (HPVs) are associated with benign and malignant neoplasms of the cervix. One of the criteria for their etiologic role requires an assessment of whether virtually all or only a small fraction of lesions contain viral genomes. DNA preparations from colposcopically directed punch biopsies of cervical lesions were analyzed by Southern blot hybridization and the polymerase chain reaction (PCR) for the presence of HPV DNA. The biopsy specimens represented different pathologic entities (koilocytosis, condyloma, cervical intraepithelial neoplasia, and invasive carcinoma). In Southern blot hybridization with radioactive probes for HPV 11, 16, 18, 31, and 33, HPV DNA was detected in 74% of the biopsy specimens (42 of 57 cases), with the predominant types being HPV 16 and HPV 18. In contrast, after PCR amplification with primers yielding fragments of characteristic size for HPV 11, 16, and 18, the analysis of the same 57 biopsy specimens revealed that all samples were positive for at least one HPV type. To exclude false-positive PCR results, controls without HPV DNA were interspersed at regular intervals, and results were evaluated only if these controls remained HPV negative. To exclude false-negative results due to failure of the reaction, a target sequence within the c-Ha-ras-1 gene was used as an internal control. All HPV typing results obtained by Southern blot hybridization were in agreement with HPV typing by PCR. The higher number of positive samples in the latter analysis stems from the increased sensitivity of PCR, which was which was effective in identifying as few as 10-100 HPV DNA molecules; in contrast, the sensitivity of Southern blot hybridization was 1 pg, or approximately 10(5) molecules of HPV DNA. The authors conclude that, with sufficiently sensitive diagnostic methods, HPV DNA can be detected in most, if not all, neoplastic cervical lesions.     

Detection of human papillomaviruses in exfoliated cervicovaginal cells by in situ DNA hybridization analysis.

A total of 851 specimens of exfoliated cervicovaginal cells and 27 specimens of male urethral smears obtained from 706 individuals with various clinical findings were examined for the presence of human papillomavirus (HPV) types 6, 11, 16, 18, 31, and 33 by in situ DNA hybridization analysis. The nonradioactive DNA in situ hybridization method used in this study showed no detectable cross-hybridization either among different types of HPV (except between types 6 and 11) or between HPV DNA and human cellular DNA. Furthermore, this system was found to be more sensitive than the Southern blotting method in detecting HPV. HPV was found in 233 of 276 (84.4%) and in 34 of 47 (72.3%) samples of cervicovaginal cells from patients with urogenital condylomata and cervical dysplasia, respectively. HPV was also detected in 6 of 39 (15.4%) women with normal cytological findings who were also symptom-free. Young women who were at low risk but were infected with HPV showed significantly reduced ratios of helper-inducer T lymphocytes to suppressor-cytotoxic T lymphocytes compared with those of uninfected normal controls (1.28 +/- 0.31 versus 2.47 +/- 0.64; P less than 0.001). This in situ DNA hybridization method can have broad application to the screening of HPV in early lesions and in normal-looking tissues and may be used to identify patients at risk of more serious or possibly malignant progression.     

Nucleic acid sandwich hybridization in detection of HPV 16 DNA: technique and its clinical application

Nucleic acid sandwich hybridization technique was used for detection of HPV 16 specific DNA in cervical scrapes. Alternating HPV 16-PstI fragments were cloned into plasmid pBR322 and phage M13mp10. pBR322-clones were used as 32P-labelled probe reagents and the M13mp10 clones as catching reagents in the assay. The detection limit of the test proved to be 1-5 X 10(5) HPV 16 molecules per test. A weak cross reaction was seen with HPV 31 DNA but not with the other types tested, e.g. HPV 6, 11, 18 and 33. Cervical scrapings obtained from 163 consecutive patients included in a prospective follow up study were analyzed for HPV 16 DNA with the sandwich hybridization method, dot-blot hybridization being used as a reference method. Sandwich hybridization assay detected 25 positive cases out of 163 specimens (15.3%). Of these 6 and 3 additional specimens were positive in dot-blot hybridization assay. HPV 16 DNA was related to higher PAP grades, and HPV 16 appeared more frequently in HPV CIN than HPV NCIN lesions. None of the infections caused by HPV 16 regressed, and 24% progressed during the follow up.     

Detection and typing of human papillomavirus DNA in the uterine cervix of japanese women by nonradioactive dot blot and southern blot hybridization

HPV infection was examined with Cytobrush in exfoliated cervical cells sampled from 347 women. HPV DNA analysis was conducted in two steps. The presence of HPV DNA was demonstrated by dot blotting and typing of HPV DNA was made by Southern blotting using biotinylated probes. Of 167 cases with cervical intra-epithelial neoplasia (CIN) and cervical carcinoma, HPV DNA was detected and typed in 25 cases (15.0%). HPV 16, 18, and 33 were found mainly, and no HPV 6 or 11 was detected. The frequency of HPV DNA was 7.1% of CIN I, 28.6% of CIN II, 54.5% of CIN III, and 50.0% of invasive carcinoma. HPV occurred in patients newly diagnosed as CIN at 25.8% and in those of diagnosed as CIN in the past and followed up, 7.6%. Of 180 healthy women, the screening test of F08830 was positive for HPV DNA in four women (2.2%). The present system proved to be useful for facilitating large-scale clinical research.     

Detection of human papillomavirus DNA in genital lesions by using a modified commercially available in situ hybridization assay.

A modified, commercially available DNA-DNA in situ hybridization test that uses biotinylated probes for the identification of human papillomavirus (HPV) DNA types 6/11, 16/18, and 31/33/35 was evaluated. HPV DNA was detected in 314 of 787 (40%) histologically abnormal genital biopsy specimens by using the ViraType in situ assay (Life Technologies, Gaithersburg, Md.), in which the hybridization time was increased from 2 to 16 h. Ninety percent of positive condyloma acuminata specimens contained HPV type 6/11 DNA. The prevalences of HPV DNA for cervical intraepithelial neoplasia I, II, and III lesions by this in situ hybridization test were 42, 54, and 55%, respectively. The combined prevalence of HPV type 16/18 and 31/33/35 DNAs increased with the severity of the lesion, while the prevalence of type 6/11 DNA decreased. HPV type 6/11 DNA was found only in 1 of 16 (6%) positive cervical intraepithelial neoplasia III specimens. HPV type 16/18 and 31/33/35 DNA was detected in 11 of 16 (69%) and 4 of 16 (25%) in situ hybridization-positive cervical intraepithelial neoplasia III specimens, respectively. Thus, the observation that certain "higher-risk" HPV genotypes are associated with upper-grade cervical precancer lesions was confirmed by this commercial hybridization system. In general, the assay was found to be well suited for use in the clinical laboratory. The ViraType in situ procedure modified for a longer hybridization time may be helpful in identifying lesions containing higher-risk HPV strains.     

Automated polymerase chain reaction for papillomavirus screening of cervicovaginal lavages: comparison with dot-blot hybridization in a sexually transmitted diseases clinic population

The aim of the present study was to compare the recently developed polymerase chain reaction (PCR) technique with conventional dot-blot DNA hybridization for human papillomavirus (HPV) detection. Cells were collected by cervicovaginal lavage from a study group of 109 women attending a sexually transmitted diseases clinic. Using a machine that we developed for alternation of temperature cycles, HPV was detected in 51% of patients by PCR. By dot-blot hybridization, 44% of the patients were positive. Concordance of combined positive and negative results between PCR and dot blot was 69%. The greater sensitivity of PCR may have accounted for 19% of specimens that were PCR positive but dot-blot negative. Unexpectedly, however, 12% of specimens were dot-blot positive but negative by PCR, and several specimens were discordant for type of HPV. Both HPV DNA tests agreed with cytology in 41% of women, and in 33% cytology was negative in the face of positive PCR and dot blot. Concordance of cytology with just PCR was 59%, and only with dot blot was 56%. Cervicography agreed with both HPV DNA tests in 41% of patients, with PCR alone in 55%, and with dot blot alone in 58%. Biopsy results did not reveal a strong correlation between histopathological criteria of HPV infection and detection of HPV DNA by either PCR or dot-blot hybridization. Thus the present study has shown that PCR is a slightly more sensitive indicator of HPV infection than dot-blot hybridization. Agreement of HPV DNA results with conventional screening tests was not strong, an observation consistent with many comparative studies by others. In conclusion, PCR is slightly more sensitive than DNA hybridization for detection of HPV, it can be used in conjunction with specimen collection by gentle lavage of the cervicovaginal epithelium, and the possibility remains that it may prove suitable as a screening test.     

Detection of human papillomavirus DNA in cervical lesions by in-situ DNA hybridization

Authors examined paraffin sections of 50 cervical specimens from 34 cases for the presence of human papillomavirus (HPV) type 6b, 11, 16, 18, 31 and 33 by in-situ hybridization using 35S-labelled HPV DNA probes. Specimens were classified according to the degree of dysplasia after histological examination. Viral nucleic acids were detected in 30 of 50 tissues (60%) in which 15 specimens had single, 10 double, 4 triple and 1 quadruple viral infections. In some cases, different viral nucleic acids were detected at separate sites in the same patient. Overall, no great variation in the frequency of each HPV was detected, but a pattern became apparent when the frequencies were compared with the grade of dysplasia. CIN II/III lesions contained one or more of the HPV types 16, 18, 31, 33 which are frequently associated with cervical carcinoma. In-situ hybridization offers sensitive means of investigating viral infection, gene expression and neoplastic transformation.     

Non-isotopic detection of HPV DNA in cervical smears using dot-blot hybridization

Infection of the cervix with specific types of the human papillomavirus (HPV) results in condylomatous, dysplastic and/or neoplastic epithelial changes. To enable routine screening of premalignant cervical lesions for HPV DNA, we have developed a sensitive method of detecting HPV -6, -11, -16, -18 and -33 in cervical scrapes using a non-isotopic, dot-blot hybridization assay. Cloned, genomic HPV DNA is labelled with biotin-11-dUTP by nick translation, and used to screen for HPV types under high stringency conditions. DNA is extracted from cervical cells and spotted on nitrocellulose membranes. Cervical cells, from 20 patients attending colposcopy were screened for HPV types. All patients had a dysplasia or condyloma. HPV DNA was isolated from 80%. The method visualized an amount of target DNA as low as 1 pg without background. Compared with Southern blot hybridization utilizing radiolabelled probe, this assay is equally sensitive and specific. The technique is easy to do, and may significantly contribute to the management of cervical dysplasia.     

Human papillomavirus infection of the uterine cervix analyzed by nonisotopic in situ hybridization

Some types of human papillomaviruses (HPVs) have been suggested to be strongly related to uterine cervical carcinoma. An attempt to detect these in formalin-fixed, paraffin-embedded sections was made by either immunohistochemical or by in situ hybridization. Anticapsid protein of bovine papillomavirus antibody labeled with peroxidase was used for immunohistochemistry, and biotin was used instead of radioisotopes to label probes for in situ hybridization, which resulted in low background and a rapid procedure. Condylomatous changes were stained immunochemically with this antibody even in invasive carcinoma, whereas the carcinoma itself was not stained. Direct correlation was demonstrated by in situ hybridization between the HPV genome and histopathological structure, which was impossible by Southern or dot hybridization. HPV DNAs were detected in the nuclei of koilocytes and dyskeratinocytes of condylomata and dysplasias. Furthermore, hybridization signals of HPV DNAs in basal and parabasal cells suggested that HPV infection had already begun in the basal cells. In the case of malignant neoplasia accompanied by dysplasia, the same type of HPV was detected both in the malignant neoplasia and accompanying dysplasia. In one case of intraepithelial carcinoma, the very small focus of carcinoma just arisen in the cells of dysplasia was identified, and both were positive for HPV 18. This fact supports the suggestion that the carcinoma arises in dysplasia. Invasive carcinomas were classified further into keratinized, large-cell nonkeratinized, and small-cell nonkeratinized types, and the positive frequency for HPV 16 decreased as the differentiation of the carcinoma decreased. In the case of keratinized type of invasive carcinoma, strong hybridization signals were prominent around the malignant pearl formation.     

The comparative test performance of dot filter hybridization (Viratype) and conventional morphologic analysis to detect human papillomavirus.

To investigate the test performance of a commercially available detection kit for human papillomavirus (HPV), the relationship between the detection of HPV by dot filter hybridization (DFH) and by standard morphologic methods was studied. Four hundred two cervical samples taken from 381 patients referred to a colposcopy clinic were examined. Human papillomavirus DNA sequences were identified and typed using commercially available anti-sense RNA probes. Simultaneous cytologic smears were obtained in 289 patients, directed biopsy samples in 284, and both smears and biopsy samples in 171 samples. Human papillomavirus DNA was detected in 164 specimens (41%), of which 24 (15%) were type 6/11, 74 (45%) were type 16/18, 39 (24%) were type 31/33/35, and 27 (16%) were untyped due to the presence of multiple positive signals. Viral types 16/18 and 31/33/35 were eight and six times more frequent in cervical intraepithelial neoplasia (CIN) II/CIN III lesions than in condyloma/CIN I, respectively. When the cytologic diagnosis was considered the standard of reference, the results of DFH for the detection of HPV were concordant in 167 (56%) paired samples. The sensitivity of DFH was 48% and the specificity was 77%. The distribution of the morphologic diagnoses in the group of false-negative results and true-positive results was similar. When the histologic diagnosis was considered the standard of reference, the efficiency of DFH was 62%, the sensitivity was 59%, and the specificity was 79%. In the subgroup of 118 samples with simultaneous smear and biopsy and at least one positive examination, 42 (36%) were positive by all three methods, 42 (36%) by two, and 34 (29%) by one, including 6 (5%) by DFH alone. Fifteen cases more were detected by the complementary use of DFH and cytology than with cytology alone. The results demonstrated that the sets of patients positive for HPV when detected by DFH or by morphologic methods were not identical but rather overlapped. The detection of HPV may be slightly improved by using DFH in addition to conventional examinations. A significant number of HPV-positive patients without a morphologic lesion and patients with low-grade lesions had HPV 16/18 or 31/33/35, suggesting a possible role for typing in establishing a risk profile. However, given uncertainties in understanding the biology of HPV-associated lesions, the role, if any, of clinical testing for HPV by DFH remains to be defined.     

Deleterious effects of formalin/acetic acid/alcohol (FAA) fixation on the detection of HPV DNA by in situ hybridization and the polymerase chain reaction.

As part of a study of archival cervical cancer specimens (1920s to 1980s) to determine whether changes have occurred in the prevalence of human papillomavirus (HPV) DNAs, investigations were performed on tissues which had been fixed in either 10% buffered formalin (NBF) or formalin-acetic acid-alcohol (FAA). HPV DNA was detected by in situ hybridization (ISH) using HPV 6, 11, 16 and 18 32P-labelled DNA probes under conditions of high stringency; and by the polymerase chain reaction (PCR) using 20-mer oligonucleotide primers to amplify 109 bases of the E6 region of HPV 16. In some instances results obtained from Southern blot hybridizations, which had been carried out on specimens of fresh cancer tissue, were available for comparison. When tissues had been fixed in NBF, HPV DNA sequences were detected in 53% of specimens by ISH and in 72% by PCR. In comparison, the rates of detection of HPV by ISH and PCR in tissues fixed in FAA were 17% and 21% respectively. These results indicate that FAA is clearly inferior to NBF for the preservation of detectable HPV DNA sequences in tissue sections.