Telomerase activity in benign and malignant human thyroid tissues.

Telomerase is a specialized ribonucleoprotein polymerase that directs the synthesis of telomerase repeats at chromosome ends. Accumulating evidence has indicated that telomerase is stringently repressed in normal human somatic tissues but reactivated in cancers and immortal cells, suggesting that activation of telomerase activity plays a role in carcinogenesis and immortalization. In this work, the status of telomerase activity during the development of human thyroid cancer was determined using telomeric repeat amplification protocol (TRAP) in 14 nodular hyperplasia, 14 adenomas, 23 papillary carcinomas and 11 follicular carcinomas. Positive telomerase activity was detected in 2 of 14 nodular hyperplasias (14%), 4 of 14 adenomas (29%), 12 of 23 papillary carcinomas (52%) and 10 of 11 follicular carcinomas (91%). The cancers that are negative for telomerase activity are mostly in early stage (stage I or II). These results suggest that telomerase reactivation plays a role during the development of thyroid cancer.     

喉癌及喉良性病变中HPV不同亚型的检测

目的：检测喉癌、癌前病变及喉良性病变HPVDNA表达的阳性率,探讨HPV感染与喉癌发的相关性。方法：运用流式荧光杂交法以及型特异性PCR方法对于46例喉癌组织、14例喉癌前病变组织及19例喉良性病变组织中HPVDNA进行检测分型。结果：运用流式荧光杂交法在79例喉病变标本中检测HPVDNA阳性率为10．13％,其中46例喉癌阳性率为6．52％;癌前病变组阳性率为35．71％;喉良f生病变均为阴性。型特异性PCR方法检测出2例喉癌HPV16阳性,与流式荧光杂交法所检测到的2例相同。结论：HPV是喉乳头状瘤的一个独立的致病因素,而与喉癌的发生关系似乎不是很密切,但尚待进一步大样本研究。     

Telomerase activity and telomere length in benign and malignant human thyroid tissues

Several studies have demonstrated that telomerase is activated and telomere length is altered in various types of tumors. In this study, we investigated telomerase activities and telomere length in 21 thyroid tumors. Telomerase activity was detected in 11 of 12 thyroid cancers and three of nine follicular adenomas. The mean telomere lengths in the cancers tissue and follicular adenomas were lower than in the respective background tissues, the differences being significant (P=0.0055 and P<0.006), respectively. Our findings suggest that change in telomerase activity and telomere length may be important for development of thyroid tumors.     

Telomerase activity in benign and malignant cytologic fluids

BACKGROUND: Telomerase is a ribonucleoprotein that maintains telomeric base pair repeats at the ends of mammalian chromosomes during DNA replication. Telomerase is expressed in various human tumors, some normal tissues, and immortalized cell lines. The assay of telomerase activity has potential as an adjunct for cancer detection in cytologic fluids. METHODS: Twenty-four unfixed cytologic fluids, including 13 ascitic fluids, 7 pleural fluids, 3 pelvic washings, and 1 bronchial washing, were prepared for polymerase chain reaction (PCR)-based telomeric repeat amplification protocol (Oncor, Inc., Gaithersburg, MD). Telomerase activity was determined by PCR. The presence of a ladder of products with 6 base pair increments, separated by polyacrylamide gel electrophoresis and detected by phosphoimaging, was considered a positive result. Results were compared with cytologic evaluation of alcohol fixed, Papanicolaou stained smears. RESULTS: Of the 14 cytologically malignant specimens, 11 (79%) contained detectable telomerase activity. Two cytologically malignant samples could not be evaluated for telomerase activity due to the presence of inhibitory substances of PCR reaction. Of the 10 cytologically negative specimens, 1 (10%) was positive for telomerase activity; this specimen was from a patient with history of both endometrial and lung carcinomas. CONCLUSIONS: Telomerase activity can be detected in malignant cytologic specimens and thus has potential as a diagnostic adjunct in cytopathology.     

Telomerase activity and human papillomavirus (HPV) infection in human uterine cervical cancers and cervical smears

Telomerase activity and human papillomavirus (HPV) infection were investigated in uterine cervical samples using molecular biology techniques. Thirteen cervical carcinomas and corresponding normal tissue from the same patient, and 102 cervical swabs were examined. Telomerase activity was detected in 12 of 13 cervical cancer tissues (92%). Of the 12 cases that showed telomerase activity, all were HPV positive, and the one case that did not show telomerase activity was HPV negative. A telomeric repeat amplification protocol assay detected telomerase activity in one out of seven normal cervical tissues (14%), and this one case was HPV positive. In cervical smear samples, telomerase activity was detected in two out of 36 normal smears (6%; both HPV positive), in 10 of 32 (31%) CIN1 (cervical intra-epithelial neoplasia) cases (three HPV positive), in four of five (80%) CIN2 cases (two HPV positive), in 15 of 21 (71%) CIN3 cases, (seven HPV positive) and in seven of eight (88%) squamous cell carcinoma cases (six HPV positive). These results suggest that telomerase activity may play some role in cervical carcinogenesis, and telomerase activity is associated with HPV infection in uterine cervical lesions.     

Incidence of human papillomavirus type 33 in premalignant and malignant skin lesions from organ transplant recipients

Human papillomavirus (HPV) type 33 belongs to potentially oncogenic types in genital cancers, but its infection corresponds to an intermediate risk for progression towards malignancy. We studied by in situ hybridization with biotinylated probes the incidence of HPV 33 infection in a series of 106 skin lesions and 12 mucosal lesions from heart and renal transplant recipients, 34 skin lesions and 17 mucosal lesions from normal population. We have shown that skin lesions from both populations could harbor HPV 33. In transplant recipients, HPV 33 was identified in 12/77 premalignant and malignant lesions and one oral leukoplakia; in the normal population, HPV 33 was detected in 2/13 warts and 2/15 mucosal lesions. The analysis of in sial hybridization signal pattern of the 17 HPV 33 positive samples suggests that a strong viral DNA signal was uniformly distributed in the nuclei of positive cell foci in 11 cases and punctate signals were seen in the nuclei of dispersed cells of 6 skin biopsies. The significance of the presence of HPV 33 DNA in skin lesions is not clear; the hybridization signal pattern may be important, mainly in premalignant actinic keratodses of organ transplant recipients although other factors are most likely involved to change the epithelial environment.     

Real-time quantitative PCR demonstrates low prevalence of human papillomavirus type 16 in premalignant and malignant lesions of the oral cavity.

PURPOSE: Human papillomavirus (HPV) type-16 has been associated with invasive squamous cell carcinoma of the head and neck. This study examines the role of HPV-16 in the progression of oral head and neck cancer by determining the quantity of HPV-16 DNA in premalignant and malignant lesions, using real-time quantitative PCR, to more accurately determine the role of HPV-16 in oral head and neck squamous cell carcinogenesis. EXPERIMENTAL DESIGN: We examined 102 microdissected premalignant head and neck lesions (85 from the oral cavity), 34 invasive oral cavity squamous cell carcinomas, as well as 18 invasive tumors known to be HPV positive by traditional molecular technology for the presence of HPV-16 DNA using real-time quantitative PCR. RESULTS: HPV DNA was detected in 1 of 102 premalignant lesions (0.98%), 1 of 34 (2.9%) invasive oral cavity carcinomas, and 14 of 18 (78%) known HPV-positive tumors. CONCLUSIONS: HPV-16 infection and integration is seldom found in oral premalignant lesions and invasive carcinoma, and therefore rarely contributes to malignant progression in the oral cavity. Furthermore, quantitative PCR is a useful technique that reliably excludes contaminated samples and those with minimal HPV DNA content that is unlikely to be significant in carcinogenesis.     

The relative distribution of oncogenic types of human papillomavirus in benign, pre-malignant and malignant cervical biopsies. A study with human papillomavirus deoxyribonucleic acid sequence analysis

The aim of the present investigation was to define the spectrum of oncogenic types of human papillomavirus (HPV) present in benign, pre-malignant (low-grade and high-grade squamous intraepithelial lesions, LSIL and HSIL) and malignant cervical lesions. The study comprises 215 HPV-positive biopsies, analysed with PCR, followed by sequence analyses of the HPV DNA. Fifeteen oncogenic types of HPV were identified. In 170 benign or pre-maligant alterations, the most common being HPV 16 (51%), HPV 31 (8%), HPV 18 (7%) and HPV 45 (6%). HPV 33, 35, 51, 56, 58, 66, and 70 occurred in about 1-4%. The prevalence of HPV 39, 52, 56, 59 and 73 was <1%. All the observed types of HPV, except 39 and 52, occurred in SIL lesions. The most common oncogenic HPV types (16 and 18), occurring in 45 invasive squamous carcinomas, comprised 76 per cent of the tumours, whereas less frequent HPV types (31, 33, 52, 56, 67, 70 and 73) were each found in about 2-4%. Double HPV infections were not observed. In conclusion, a total of 15 different oncogenic HPV types were identified, of which 13 types were present in pre-malignant cervical lesions and 9 in malignant lesions. This information may have some relevance when HPV analyses are considered as an adjunct to the organised screening of cervical cancer and for those working with the development of HPV vaccines for the prevention of cervical cancer.     

Estrogen and progesterone receptors in cervical human papillomavirus related lesions.

According to recent studies showing that human papillomavirus (HPV) infections can be influenced by sex steroid hormones, we performed estrogen (ER) and progesterone (PgR) receptor assays in fresh frozen biopsies of genital-HPV-related lesions. Seventy-three women with normal cervix, condyloma, low- and high-grade CIN and squamous carcinoma were evaluated in comparison with 15 persons with vulvar and 9 with penile papillomavirus-associated lesions. HPV genotypes were determined by dot-blot hybridization. Non-cervical lesions did not express HR. Condyloma on squamous metaplasia of the cervix and high-grade CIN expressed high levels of HR, particularly PgR (mean 4,086 and 4,518 fmoles/g tissue, respectively). Cervical squamous carcinoma expressed very low concentrations of PgR in a limited number of cases. High levels of PgR were correlated with high-grade CIN (p less than 0.05), HPV16-18-associated lesions (p less than 0.01) and ER were correlated to HPV6-11-related lesions (p less than 0.01). The levels were independent of age, cycle stage and oral contraception. Morphological localization of PgR, using an immunocytochemical method using a monoclonal antibody (MAb) (PR-ICA), showed intense homogeneous staining in the nuclei of the stromal fibroblasts underlying dysplastic epithelium and condyloma on squamous metaplasia. These results suggest that, under in vivo conditions, sex steroid hormones, particularly progesterone, may act indirectly on HPV-infected epithelial cells and be implicated as co-factors in HPV-related cervical neoplasia. They could explain the relative predisposition to malignant transformation of the cervix as compared with vulvar and penile mucosa.     

The prevalence of human papillomavirus in oral premalignant lesions and squamous cell carcinoma in comparison to cervical lesions used as a positive control

Background  

Previous reports concerning the prevalence of human papillomavirus (HPV) in oral squamous cell carcinoma (OSCC) have observed varied results. The aim of this study was to evaluate the prevalence of HPV in oral premalignant lesions (OPL) and OSCC. For accurate HPV detection in oral lesions, comparative analysis was performed on cervical lesions as positive controls.     

Management of cervical premalignant lesions

Treatment of cervical premalignant lesions (cervical intraepithelial neoplasia; CIN) of different grades is very effective, simple, and safe. The entire transformation zone of the cervix needs to be treated either by an ablative technique (cryotherapy or thermal ablation) or an excisional technique (large loop excision of transformation zone or cold knife conization); the choice of treatment depends on the size and location of the lesion and the type of the transformation zone. The cure rate after ablative treatment of high-grade CIN may be little lower than that after excisional treatment. The simplicity of the technique, low complication rate, and lesser cost make ablative technique the treatment of choice in the low resourced settings for the eligible lesions. In situations where organizing colposcopy and histopathology services is challenging, simple algorithms like screening with visual inspection with acetic acid test and immediate ablative treatment of the visual inspection with acetic acid-positive women has been recommended by the World Health Organization. Such a strategy is effective in preventing subsequent development of high-grade CIN and also ensures high compliance of the screen positive women to treatment.     

K-ras activation in premalignant and malignant epithelial lesions of the human uterus

We previously reported (Cancer Res., 50:6139-6145, 1990) a significant frequency of activating point mutations in codon 12 of the K-ras oncogene in endometrial adenocarcinomas of the uterine corpus (series 1). To further define the role of ras activation in the development of endometrial adenocarcinoma, we surveyed cystic, adenomatous, and atypical hyperplasias of uterine endometrium and additional cases of endometrial and cervical carcinoma (series 2) for the presence of activating mutations in cellular protooncogenes of the ras family. Polymerase chain reaction was performed from deparaffinized sections of formalin-fixed paraffin-embedded tissue. We screened for point mutations in codons 12, 13, and 61 of the K-, H-, and N-ras genes by dot blot hybridization analysis with mutation-specific oligomers. Mutations in K-ras were also confirmed by direct genomic DNA sequencing. Of 19 endometrial adenocarcinomas in series 2, point mutations in ras genes were found in 7 tumors. Six contained single-base substitutions, five in codon 12 of K-ras and one in codon 12 of N-ras. The seventh tumor contained two different point mutations in codon 12 of K-ras. In one endometrial adenocarcinoma, tumor cells with point mutations in K-ras were predominantly localized to a portion that had a more aggressive histological pattern. In endometrial hyperplasia, K-ras mutations, one in codon 12 and one in codon 13, were found in 2 of 16 hyperplasias histologically classified as atypical and clinically considered premalignant. None of 6 adenomatous hyperplasias and none of 12 cystic hyperplasias, the latter of which is considered clinically benign, contained any detectable ras mutations. No mutations in H-ras were detected in either carcinomas or hyperplastic tissue.     

Human papillomavirus: its identity and controversial role in oral oncogenesis, premalignant and malignant lesions (review)

Human papillomaviruses (HPVs) are a group of host-specific DNA viruses, with a remarkable epithelial cell specificity: they have been reported principally in the ano-genital tract, urethra, skin, larynx, tracheo-bronchial and oral mucosa. More than 100 different HPV types have been identified and classified as high (e.g. 16, 18, 31) or low (e.g. 11, 42, 36) -risk (HR and LR), based on their association with cervical carcinoma. The carcinogenic role of HR-HPV revolves mainly around two of its oncoproteins: HPV-E6 which promotes degradation of the p53 tumour suppressor gene product and HPV-E7 which modifies the pRb tumour suppressor gene product, inhibiting the activity of TGF-beta2. Since these viral oncoproteins are capable of transforming primary human keratinocytes from either genital or upper respiratory tract epithelia, they have been considered to play a role in disrupting cell-cycle regulatory pathways leading to a genetic progression to ano-genital cancer and, possibly, also to oral squamous cell carcinoma (OSCC). Recently, the oncogene HPV-E5 has also been found to transform cells by modulating growth factor receptors. On the basis of the high, although very variable, frequency of HR-HPV in OSCC, an oral malignant potential of HPV infection has been hypothesised but not definitively confirmed. Major aims of this review are to update the understanding of HPV activities with respect to oral oncology and to comment on the HPV DNA reported frequencies in OSCC and potentially malignant oral lesions. A computer database search was performed, through the use of MEDLINE (PubMED) and Cochrane Library, for the last three decades. Search key words used were: human papillomavirus, HPV and cancer, HPV and oral lesions, HPV and oral premalignant lesions, HPV and oral cancer, HPV and HNSCC, HPV and oral mucosa. The search was of all fields, all languages and all dates available.     

Glutathione localisation in benign and malignant human breast lesions

Reduced glutathione (GSH) has been demonstrated in benign and malignant human breast lesions using a newly developed histofluorescence technique. GSH was present in every lesion and in each case was localised to the epithelium. A semi-quantitative assessment revealed a moderate amount of GSH in normal epithelium and fibroadenoma and a high level in apocrine metaplasia, epitheliosis and intraduct carcinoma. Invasive ductal carcinoma contained a variable amount of GSH. Correlation between fluorescence intensity and histological grade of ductal carcinomas was almost statistically significant but a relationship to oestrogen receptor status was not detected. The rapid assessment of GSH in breast cancer may aid in the selection of optimum chemotherapeutic regimens.     

Expression of tropomyosin isoforms in benign and malignant human breast lesions.

High molecular weight tropomyosins (tms) are commonly down-regulated in fibroblasts transformed by oncogenes. Previous studies have also demonstrated that specific tm isoforms are down-regulated in human breast carcinoma cell lines. We examined tropomyosin isoforms in cells prepared from non-cancerous breast lesions and primary human breast carcinomas. The average level of expression of all three high molecular weight tm isoforms (tm 1-3) in carcinomas was generally found to be less than 25% of that observed in non-cancerous breast lesions. Interestingly, the expression of tm 1 was found to be 1.7-fold higher in primary tumours with metastatic spread to axillary lymph nodes compared with primary tumours with no evidence of metastasis (p<0.05). Similarly, tm 1 expression was higher in two 12V-H-ras transformed fibroblast cell lines capable of experimental metastasis compared with three weakly metastatic cell lines. We conclude from these studies that expression of high molecular weight tm isoforms is low in primary breast carcinomas, and that metastatic tumours express relatively high levels of tm 1.     

Detection of human papillomavirus DNA in benign and malignant sinonasal neoplasms

Infections with human papillomaviruses are divided basically into three different infection types: those producing specific clinically visible lesions, those remaining subclinical, and those being latent. The assumed infection type thought to be present in tissue specimens has influence on the conclusions that can be made from an analysis, i.e. whether or not the HPV infection has a causal relationship with other epidemiological or molecular investigation observations. To determine whether HPV DNA detection in different entities of the upper aerodigestive tract represents a coincidental, persistent/latent or specific infection, 20 clinically intact mucosa specimens of the upper aerodigestive tract, 20 sinonasal polyps, 26 inverted papillomas, and 20 squamous cell carcinomas of the paranasal sinuses were investigated. HPV DNA was not detectable in specimens derived from clinically intact mucosa or in nasal polyps. Yet, three out of 26 inverted papillomas were HPV-positive, each showing double infection with HPV6 and 11. Four out of 20 squamous cell carcinomas were HPV16 positive. To our knowledge, we are presenting the first study contemporaneously analyzing benign as well as malignant non-proliferative and proliferative mucosal entities whilst applying identical methodical standards. The data corroborate the hypothesis that HPV DNA demonstration in tissue specimens represents a specific infection of the mucosa of the upper aerodigestive tract. It can thus be assumed that there is a causative involvement of HPV infections in the alteration of cell proliferation and in the case of infection with high risk HPV types even on progression to malignant transformation.     

人乳头瘤病毒DNA甲基化与宫颈病变程度的关系

高危型人乳头瘤病毒（human papillomaviruses,HPV）持续性感染是导致宫颈病变及宫颈癌的必要条件。高危型HPV 表观遗传学的改变在宿主细胞癌变中起一定作用。目前研究表明高危型 HPV 甲基化可作为宫颈病变筛查的预测生物标志物,且其检测的有效方法主要包括甲基化特异性PCR、亚硫酸盐测序、焦磷酸测序等。本文重点阐述了高危型 HPV甲基化导致宫颈癌的主要机制,描述了宫颈病变筛查标志物,并综述了高危型 HPV DNA甲基化的检测方法。