Pitfalls in the epidemiologic classification of human papillomavirus types associated with cervical cancer using polymerase chain reaction: driver and passenger

Cervical cancer is a common malignancy in women worldwide, and it has now been established that the human papillomavirus (HPV) is both necessary and causal for these lesions. HPV itself is both ubiquitous and markedly heterogeneous but can nevertheless be classified as either a high-risk type or a low-risk type based upon its frequency of detection in cervical cancer. Given that the association between HPV and cervical cancer is causal, the classification of this virus has been strengthened by large-scale epidemiologic studies and is widely accepted across many disciplines. It is evident, however, that cervical cancer is frequently associated with multiple HPV types. Therefore, it is crucial to distinguish causal types of HPV (drivers) from noncausal types (passengers) in cervical lesions. In this review, we highlight the current pitfalls of using polymerase chain reaction methods instead of Southern blot hybridization for detecting HPV and discuss the distinction between driver and passenger HPVs with regard to the viral type, the length of the viral genome, and the levels of viral DNA associated with cervical cancer. Finally, we newly propose three categories of HPV instead of two risk groups, based on similarities between viral genes.

Relationships between 80 human papillomavirus genotypes and different grades of cervical intraepithelial neoplasia: association and causality

To clarify the causal relationship between human papillomavirus (HPV) and cervical intraepithelial neoplasia (CIN), we analyzed 386 unfixed biopsy specimens by blot hybridization at Tm -40 degrees C, targeting 38 skin and 42 genital HPVs. By the recognition of PstI, BanI, and MspI cleavage patterns, single genital, but no skin's HPVs were identified with more than 10 copies per cell in 354 CIN (88 CIN I, 94 CIN II, and 172 CIN III). HPVs 40, 42, 43, 54, 62, or 71 was found in 10 CIN I, while HPVs 18, 30, 39, 51, 56, 59, 66, 68, 69, or 82 was found in 35 CIN I, 20 CIN II, or 8 CIN III. On the other hand, HPVs 16, 31, 33, 35, 52, 58, or 67 was identified in 43 CIN I, 74 CIN II, or 164 CIN III. The results are strongly indicative that most genital HPVs have potency to induce CIN I; however, HPV 16 and its closely related types are able to efficiently induce CIN III. We discuss the definition of causal HPV for CIN with regard to viral prevalence and viral load.

Molecular cloning and nucleotide sequence analysis of a novel human papillomavirus (Type 82) associated with vaginal intraepithelial neoplasia

The genome of a novel human papillomavirus (HPV-82) was cloned from a vaginal intraepithelial neoplasia grade I. In our series of 291 biopsy specimens, HPV-82 was identified in one case each of cervical intraepithelial neoplasia grade II and grade III by blot hybridization. The histological localization of HPV-82 DNA in the three lesions was confirmed by in situ hybridization. The results indicated that HPV-82 is an etiologic agent for vaginal and cervical intraepithelial neoplasia. By nucleotide sequence similarity of L1 open reading frame (ORF), HPV-82 was closely related to HPV-26, -51, and -69. To know the precise relationship between the HPVs, we determined the complete sequence of HPV-82, as well as that of HPV-69. Sequencing revealed that the four HPVs had no initiation codon in the E5 ORF and had extensive nucleotide sequence similarities in all ORFs. In addition, they exhibited unique frame position patterns for ORFs, different from those of the other genital HPVs.

[Serovar distributions of cervical Chlamydia trachomatis isolated in Nagano Prefecture]

Between 1992 and 1998, serotyping of 82 Chlamydia trachomatis cervical isolates were examined by micro-IF method in Nagano Prefecture. Of these, 17 isolates (20.7%) were serovar E, 15 (18.3%) were serovar F, 14 (17.1%) were serovar D and 10 (12.2%) were serovar G, and the isolates typed these serovars were found to be 68.3% whole. Furthermore, serovars B (7.3%) and K (9.8%) were comparatively frequently found. From 1992 to 1994, the number of isolates of B-complex, intermediate and C-complex were 18, 17 and 6, respectively. On the other hand, from 1995 to 1998, the number of the isolates were 19, 8 and 14, respectively. The distribution of serovars of C. trachomatis tended to fluctuate from serovars D and E to F and G as the patients grew older. Moreover, serovar E isolates were only detected from patients less than 40 years old. Although most of the serovar I isolates were detected from the patients with vaginal discharge, the other isolates did not clearly indicate the relationship of serovars and clinical symptoms.

Serum carotenoids and vitamins and risk of cervical dysplasia from a case-control study in Japan

The relationships between risk of cervical dysplasia and dietary and serum carotenoids and vitamins were investigated in a case-control study. Cases were 156 women who attended Papanicolaou test screening in nine institutes affiliated with Japan Study Group of Human Papillomavirus (HPV) and Cervical Cancer and had cervical dysplasia newly histologically confirmed. Age-matched controls were selected from women with normal cervical cytology attending the same clinic. Blood sample and cervical exfoliated cells were obtained for measuring serum retinol, alpha-carotene, beta-carotene, zeaxanthin/lutein, cryptoxanthin, lycopene and alpha-tocopherol and for HPV detection. Higher serum level of alpha-carotene was significantly associated with decreased risk of cervical dysplasia after controlling for HPV infection and smoking status (odds ratio (OR) = 0.16, 95% confidence interval (CI) 0.04-0.62 for the highest as compared with the lowest tertile). Decreased risk for the highest tertile of serum lycopene (OR = 0.28) was marginally significant. Decreased risks observed for the highest tertiles of beta-carotene (OR = 0.65) and zeaxanthin/lutein (OR = 0.53), were not statistically significant.

Human papillomavirus infection and other risk factors for cervical intraepithelial neoplasia in Japan

Various risk factors were investigated in 167 cervical intra-epithelial neoplasia (CIN) case and control pairs in Japan. CIN cases showed evidence of nine known risk factors including smoking and sexual behaviour. However, after adjustment for papillomavirus infection, the highest determinant, the only remaining risk factors were: being married, early age at first pregnancy and multiparity.

Distinct manifestations of human papillomaviruses in the vagina

To clarify the pathogenic relationships between human papillomavirus (HPV) and vaginal intraepithelial neoplasia (VAIN), we examined 71 vaginal biopsy specimens by histopathology and immunohistochemistry and analyzed the presence of HPV DNA by blot hybridization at Tm - 40 degrees C using an HPV 58 probe (PBM-58 method). We found 27 cases of VAIN in patients with previous hysterectomy or antecedent or concomitant cervical intraepithelial neoplasia (CIN) and 44 cases of VAIN in patients without any abnormal findings on the cervix and the vulva. Histopathologically, 53 of 71 cases were graded as VAIN I and 15 and 3 cases were VAIN II and III, respectively, while 59 cases showed positivity for HPV capsid antigen by immunohistochemistry. Using the PBM-58 method, all 71 VAIN cases harbored a single HPV type at more than 1,000 viral copies per cell. We identified 15 different types (HPV 16, 18, 30, 31, 35, 40, 42, 43, 51, 52, 53, 54, 56, 58 and 66). Furthermore, we molecularly cloned 7 novel prototypes (HPV 59, 61, 62, 64, 67, 69 and 71) from VAIN I. Our results are strongly indicative that HPVs are etiologic agents of VAIN, like in the case of CIN. The distinct manifestations of HPV infection in the vagina are discussed in comparison with those in the cervix.

Identification of genital human papillomaviruses in cervical biopsy specimens: segregation of specific virus types in specific clinicopathologic lesions

We have established a critical identification method for the full spectrum of genital human papillomaviruses (HPVs) in clinical specimens. It was based on the recognition of PstI, BanI and MspI cleavage patterns of HPV DNA detected by blot hybridization with HPV 58 DNA probe at Tm -40 degrees C. By this method, we identified 24 different types of genital HPV including 5 novel types (HPV 59, 61, 62, 64 and 67) in the specimens collected at one hospital and found almost all the HPVs with the authentic cleavage patterns of their respective prototypes. In 235 cervical biopsy specimens, HPV 6 or 11 was found in exophytic condyloma acuminatum (15/15) but not in any cervical intraepithelial neoplasia (CIN) specimens. In contrast, HPV 18, 30, 43, 54, 56, 59, 62, 66 and 67 were identified in CIN I (28/71) or II (4/56) but not in CIN III, while HPV 16, 31, 33, 35, 39, 51, 52 and 58 were identified in CIN III (83/93) as well as in CIN I (34/71) and II (47/56). The result indicates that heterogeneous genital HPVs prevail all over the world. In addition, HPV 6 and 11 are etiologic agents only of exophytic condyloma, whereas the other HPVs are etiologic agents of CIN with the segregation of specific HPVs in CIN III. We propose a new clinicopathologic grouping of genital HPVs founded on nucleotide homology of the HPV genome.

[Normal-sized ovary carcinoma syndrome: histopathological analysis of 14 cases]

Fourteen cases of "normal-sized ovary carcinoma syndrome" (diffuse metastatic malignant disease of the abdominal cavity of the female, with normal-sized ovaries, with no origin assigned definitively by intraoperative or preoperative evaluation, Feuer et al., 1989) were analyzed histologically, histochemically, immunohistochemically and ultrastructurally. Through these studies, 14 cases were divided into 11 primary peritoneal tumors (4 diffuse malignant mesotheliomas and 7 serous surface papillary carcinomas) and 3 metastatic peritoneal tumors (2 ovarian tumors and 1 appendicular tumor). To distinguish serous surface papillary carcinomas from epithelioid diffuse malignant mesotheliomas, examinations such as hyaluronidase digestion test, electron microscopy, and immunohistochemical studies using antibodies for Ber-EP4 and Vimentin were found to be useful. In order to achieve an accurate prognosis of normal-sized ovary carcinoma syndrome, it seems necessary for us to accumulate more information on this syndrome.

Intact sex determining region Y (SRY) in a patient with XY pure gonadal dysgenesis and a twin brother

A patient with an apparently normal 46, XY karyotype, suffering from pure gonadal dysgenesis and of short stature was investigated. The patient, who was growth retarded, was a 30-year-old married Japanese woman with a history of primary amenorrhea and infertility with a weight of 42 kg and a height of 146 cm. She has a phenotypically and karyotypically normal dizygotic twin brother with normal development. Southern-blot and polymerase chain-reaction analyses revealed no apparent deletions in the patient's Y chromosome, including the sex-determining region Y (SRY). The DNA sequencing of the SRY gene showed a 100% nucleotide sequence identity with the reported cloned sequence. Sex reversal in the present case may be due to mutation at a locus other than SRY in the sex determining pathway, a gene potentially involved in the determination of human constitution.

Detection of capsid antigen of human papillomavirus (HPV) in benign lesions of female genital tract using anti-HPV monoclonal antibody

We established a murine monoclonal antibody (K1H8) to human papillomavirus (HPV) using alkaline-disrupted virions of HPV type 1 (HPV-1) as the immunogen. K1H8 recognized a 57 kD capsid protein of HPV-1 and detected the antigen in paraffin sections of formalin-fixed tissue. With K1H8, we examined immunohistochemically 68 biopsy specimens obtained from the female genital tract. The specimens were histologically condyloma acuminatum or koilocytotic lesions with or without dysplasia and each specimen was found to harbour a single type of genital HPV, such as types 6, 11, 16, 18, 31, 33, 42, 51, 52, 56, and 58, by Southern blot hybridization analysis. The antigen was localized in the nuclei and occasionally in the cytoplasm of squamous cells showing koilocytotic changes. Eighty-four per cent of the specimens (57 cases) showed positivity for the antigen, indicating that K1H8 is a broadly-reactive antibody to various genital HPVs. The results suggest that benign mucosal lesions of the female genital tract are more frequently associated with viral production and are a potential source of transmission.

Independent association of antibodies against human papillomavirus type 16 E1/E4 and E7 proteins with cervical cancer

The E4 open reading frame (ORF) of human papillomaviruses (HPVs) is transcribed in abundant mRNAs encoding an E1/E4 fusion gene during the productive infection, and the HPV 16 E7 ORF encodes an oncoprotein detectable in the cell lines derived from cervical carcinoma. We examined 421 human sera, which included 108 samples from the patients with cervical carcinoma, for the presence of IgG antibodies against the HPV 16 E4 and E7 proteins by enzyme-linked immunosorbent assay. Bacterially expressed fusion protein lac-E1/E4 and nonfusion protein E7 were purified and used as antigens. All of the 22 serum samples positive for anti-E7 antibody and the 11 out of 15 samples positive for anti-E1/E4 antibody were from the patients with cervical carcinoma, but only one sample was found to contain both anti-E1/E4 and anti-E7 antibodies. These findings show specific and independent association of these antibodies with cervical carcinoma.

[Uterine cervical carcinoma and human papillomaviruses]

For many years it has been thought that a significant proportion of cervical cancer could be attributed to sexually transmitted agents, such as sperm, smegma, Treponema pallidum, Gonococcus and herpes simplexvirus type 2. Recent advances of molecular biology, however, have revealed that human papillomavirus (HPV) might be the most causative virus of the disease. Since HPV type 16 DNA was found in a patient with cervical cancer in 1983, many HPV types have been cloned from cervical cancers, also from premalignant lesions (intraepithelial neoplasias). In Japan, we have found 6 new types of HPV (HPV 58, 59, 61, 62, 64, 67) in the female genital tract so far. Especially, HPV 58, which was cloned from a patient with cervical squamous cell carcinoma and was already fully sequenced, is thought to be an important agent for the development of cervical cancer as well as HPV 16. Now we are investigating extensively to clarify the real relationship between genital HPV infection and cervical cancer.

Clinicostatistical study of ovarian tumors of germ cell origin

Ovarian tumors of germ cell origin consisted of 440 dermoid cysts, 5 struma ovariis, 3 immature teratomas (G1, G2), 2 carcinoids, 8 dysgerminoma, 3 yolk sac tumors, one choriocarcinoma, 4 dermoid cysts with malignant transformation, and one immature teratoma (G3) of a total of 1,387 ovarian tumors. The patients' mean ages ranged between 17.3 years to 31.9 years, but the mean ages of those with carcinoid and dermoid cyst with malignant transformation were 46.0 and 53.0 years, respectively. In dermoid cyst bilaterality was 17.3% and occurrence during pregnancy or puerperium was 19.6%. In benign tumors, torsion of pedicle and association with pregnancy or puerperium were frequent unlike common epithelial carcinoma, but ascites was rare. Abdominal tumor, pain and metromenorrphagia were the main symptoms, but abdominal distension was scarce with dermoid cysts. The rate of malignant transformation of dermoid cysts was 0.9% overall but 4.3% in patients over 40 years. The prognosis for borderline germ cell tumors was good.

Clinicostatistical study of low potential malignancy ovarian cystadenoma (borderline cases)

The number of ovarian cystadenoma of low potential malignancy (abbreviation: LPM) was 31 (5.7%) among common epithelial tumors [benign cystadenoma = 400 (74.0%), carcinoma = 110 (20.3%)]. Their mean ages, bilaterlity, frequency of ascites and nulligravidity were situated intermediately between those of benign cystadenoma and carcinoma. Abdominal tumor, distention, pain and metromenorrhagia were the main symptoms, although gastrointestinal complaints were rare in LPM cystadenoma. With LPM cystadenoma, 19 (61.3%) patients were at stage I, 7 (22.6%) at stage II and 5 (16.1%) at stage III, but with carcinoma, 44 (40.0%) were at stage III-IV [33 (30.0%) at stage I, and 31 (28.2%) at stage II]. The 5-year actuarial survival rate was 90% for LPM cystadenoma, but 43% for carcinoma. These results suggest that the clinical and biological features as well as the histological definition of LPM cystadenoma are situated intermediately between those of benign cystadenoma and carcinoma.

Human papillomavirus in exophytic condylomatous lesions on different female genital regions

Clinically diagnosed exophytic condylomatous lesions on the vulva (20 cases), vagina (5 cases), and cervix (9 cases) were examined pathologically, and human papillomavirus (HPV) types present in those lesions were identified by Southern blot hybridization analysis. All vulvar and vaginal lesions showed typical histopathological features of classical condylomata, and HPV 6 and 11 were found in 15 vulvar and 3 vaginal lesions and in 5 vulvar and 2 vaginal lesions, respectively. In 5 cervical lesions with typical condylomatous changes, HPV 6 or 11 was also detected; however, HPV 16 was found in 2 cases of cervical lesion surrounded by prominent intraepithelial neoplasia, and HPV 31 was found in 2 cases of slightly elevated lesion with intraepithelial neoplasia. These observations suggest that HPV 6 and 11 have the potency to induce the specific pathological changes, condylomatous, in any regions of the female lower genital tract.

Evaluation of DNA probe test for clinical diagnosis of chlamydial and gonococcal infections of the uterine cervix

A DNA probe test (Gen-Probe) was compared with cell culture and an enzyme immunoassay method (Chlamydiazyme) for the clinical diagnosis of cervical chlamydial infection. A total of 127 specimens (95 before treatment and 32 after treatment) were obtained from 95 patients considered members of a high risk population. Forty-five (47.4%) of the 95 cases examined before treatment were positive for the DNA probe and the sensitivity, specificity, positive predictive value and negative predictive value of the test vs cell culture were 78.4, 93.4, 88.9, and 86.6%, respectively. Comparison of these data with those of Chlamydiazyme showed that the DNA probe method was a little less sensitive but much more specific. The kit could also detect gonococcal infection with sufficient accuracy in the same specimen as used for Chlamydia trachomatis, and was considered to be a useful tool as another noncultural alternative for clinical diagnosis of sexually transmitted chlamydial and gonococcal infections of the uterine cervix, although further improvement on the kit for Chlamydia trachomatis is expected.

Molecular cloning of a novel human papillomarvirus (type 58) from an invasive cervical carcinoma

A novel human papillomavirus type (HPV) was cloned from an invasive cervical carcinoma. The viral clone showed no homology with other known prototypes of HPV (HPV-1 through HPV-57), except HPV-33 by Southern blot analysis under stringent conditions. It showed less than 20% homology to HPV-33 by reassociation kinetic analysis. The restriction endonuclease map of the clone was different from those of other HPV types and its predicted genome organization surmised by hybridization with subgenomic fragment probes of HPV-33 DNA showed the typical HPV genome organization. The results indicate that this clone is a new type of HPV, designated as HPV-58, distinct from the other known types of HPV. HPV-58 was detected in none of 6 specimens of cervical condylomata acuminata, in 7 of 58 specimens of cervical intraepithelial neoplasia, and in 4 of 50 specimens of invasive cervical carcinoma studied in Nagano prefecture, Japan.

Both episomal and integrated forms of human papillomavirus type 16 are involved in invasive cervical cancers

The form of human papillomavirus type 16 (HPV 16)DNA in specimens of invasive cervical cancer was investigated. High molecular, tandem repeats of viral sequences were detected as several distinct bands, using a low concentration (0.5%) agarose gel and a no-cut enzyme (HindIII) for HPV 16. Two-dimensional agarose gel electrophoresis allowed us to differentiate between the episomal multimeric and the integrated forms of viral DNA. All 34 cervical cancer specimens showed the characteristic PstI cleavage pattern of HPV 16 DNA, indicating that a full viral genome was present in these specimens, and 24 specimens (70%) showed only episomal monomeric or multimeric forms without the integrated form of HPV 16 DNA. The remaining 10 specimens (30%) showed integrated multimeric forms of viral DNA, either without the episomal form (8 specimens) or with the concomitant episomal form (2 specimens). In addition, a metastatic tumor in a pelvic lymph node showed only the episomal form of viral DNA, whereas its primary cervical cancer showed both episomal and integrated forms of viral DNA. There was no correlation between the forms of viral DNA and the clinical stages of tumors. The result indicates that both episomal and integrated forms of a complete HPV 16 DNA are involved in invasive cervical cancers.

[The significance of serum specific IgA antibody to Chlamydia trachomatis in the diagnosis and treatment of chlamydial infection in female genital tract]

Chlamydia trachomatis IgA and IgG antibody titers were determined by indirect immunoperoxidase assay in sera of 88 female patients with C. trachomatis-positive cervicitis and 55 C. trachomatis negative healthy controls. Serial serum samples obtained until 66 weeks after treatment were also studied for IgA and IgG antibodies in 28 of the 88 patients with chlamydial cervicitis. In the 88 patients, the presence (94.3%) of antibody (titer greater than or equal to 16) was comparable to that (100%) of IgG antibody (titer greater than or equal to 32), but in healthy controls the presence (5.4%) of IgA antibody was lower than that (30.6%) of IgG antibody. Serum IgA antibody decreased gradually and was undetectable (titer less than or equal to 8) at 20 weeks after treatment in 78.6% of the 28 patients. Serum IgG antibody persisted at stable levels within the same period. These data suggest that the presence of serum IgA antibody to C. trachomatis is correlated with active C. trachomatis infection of the female genital tract.

Detection of human papillomavirus type 16 DNA and papillomavirus genus-specific antigens in vulva and cervix from patients with Bowenoid papulosis

The warty disordered lesions of the vulva in three female patients were diagnosed as Bowenoid papulosis on the basis of clinical and histopathological findings. In all three vulvar lesions, human papillomavirus type 16 (HPV 16) DNA was identified by Southern blot hybridization and papillomavirus genus-specific (PGS) antigen was detected in one case immunohistochemically. Furthermore, colposcopic examination revealed the presence of abnormal uterine cervical lesions in two cases. They were found to be intraepithelial neoplasia which harbored HPV 16 DNA and were positive for PGS antigen.

Experience with the treatment of metastatic ovarian carcinoma

Metastases from non-genital sites comprise about one in six of our malignant ovarian tumors. The mean age of our 24 patients with such metastases was 43.1 years and 81% had bilateral ovarian metastases. Out of the 24 patients we studied, 21 had a gastric primary. The overall survival rate was 41.7% in 6 months, 25.0% in 1 year and 12.5% in 2 years. Patients with no extraovarian metastases had a survival rate of 75.0% at 6 months, 62.5% at 1 year and 25.0% at 2 years after operation.

Hydrops fetalis caused by intrauterine human parvovirus infection

During a large outbreak of erythema infectiosum in 1987 in Toyama prefecture, Japan, a 32-year-old woman acquired a mild rash on her arms and legs at 18 weeks of gestation. At 26 weeks and 4 days of gestation, the fetus died by hydrops fetalis and pregnancy was terminated. Histological studies of the fetus revealed degeneration of erythroblastic cells in the liver and bone marrow. Extensive extramedullary hematopoiesis and hemosiderin deposits were observed in the liver. Antibody response to human parvovirus B19 virus was demonstrated in maternal sera by ELISA. Furthermore, dot hybridization with the molecularly cloned DNA probe revealed the presence of human parvovirus DNA sequence in the fetal liver, spleen, lung, kidney and placenta. This report describes the first case in Japan of hydrops fetalis caused by human parvovirus B19 infection.

Pregnancies following conservative treatment of malignant ovarian tumors

Sixteen patients with malignant ovarian tumors were treated conservatively; 1 had a serous cystadenoma of low potential malignancy; 6 had a mucinous cystadenoma of low potential malignancy; 2 had a pure dysgerminoma; 2 had a mature solid teratoma; 3 had a mucinous cystadenocarcinoma; and 2 had an endodermal sinus tumor. Postoperative chemotherapy was given in 12 cases and 1 patient with a pure dysgerminoma had radiotherapy. Eighteen pregnancies occurred in 13 patients. One full-term and one 8 month premature infant died in utero, and 2 infants had malformations; the other 14 infants are all well. The patient with moderately differentiated mucinous cystadenocarcinoma who delivered a premature infant and 2 patients with endodermal sinus tumors died of recurrence.

Desmosome-like structures between tumor cells and endothelial cells in choriocarcinoma heterotransplanted into the nude mouse: a preliminary report

Tumor cells obtained from the metastatic focus of the lung of a 51-year-old woman with choriocarcinoma were transplanted in the subcutaneous tissue of the nude mouse and studied with an electron microscope. At the junctional zone between the tumor and the invaded cells a desmosome-like structure, between the transplanted tumor cells and endothelial cells, was observed in the nude mouse. Although this finding seems quite unusual, it may be related to the unique character of the early trophoblast.