Biomedical subjects

S Y Liao

Publications and source records attributed to S Y Liao.

At least 19 recordsLinked to original sources

PubMed2005

Approximation of flammability region for natural gas-air-diluent mixture.

The growing implementation of exhaust gas recirculation (EGR) in reducing NO(x) emissions of engine is of paramount motivation to perform a fundamental research on the flammability characteristics of fuel-air-diluent mixtures. In this work, the influences of EGR on the flammability region of natural gas-air-diluent flames were experimentally studied in a constant volume bomb. An assumption of critical burning velocity at flammability limit is proposed to approximately determine the flammability region of these mixtures. Based on this assumption, an estimation of the flammability map for natural gas-air-diluent mixtures was obtained by using the empirical formula of burning velocity data. The flammability regions of natural gas-air mixtures with EGR are plotted versus the EGR rate. From the comparison of estimated results and experimental measurements, it is suggested that the accuracy of prediction is largely dependent upon the formula of burning velocity used. Meanwhile, the influence of pressure on the critical burning velocity at flammability limit is also investigated. On the basis of the pressure dependence criterion, the estimation was performed for the circumstance of high temperature and pressure, and the prediction results still agree well with those of experiments.

Air↗

PubMed2005

Experimental study of flammability limits of natural gas-air mixture.

Flammability limits data are essential for a quantitative risk assessment of explosion hazard associated with the use of combustible gas. The present work is to obtain the fundamental flammability data for prevention of the hazards in the practical applications. Experiments have been conducted in a constant volume combustion bomb, and the fuel considered here is natural gas (NG). The pressure histories in the combustion bomb are recorded and a criterion of 7% pressure rise has been used to judge a flammable mixture. The effects of ethane on NG-air flammability limits have been investigated. By adding diluent (carbon dioxide, nitrogen or their mixture) into NG-air mixture, the dilution effects on the flammability limits have been explored as well, and the results are plotted as functions of diluent ratio.

Air↗

PubMed2005

Intratumoral oxygenation of invasive squamous cell carcimoma of the vulva is not correlated with regional lymph node metastasis.

INTRODUCTION: Tumour hypoxia has been found to be associated with tumour aggressiveness. Our primary aim was to explore the relationship between pretreatment tumour oxygenation in primary vulvar carcinoma and nodal status. Our secondary objective was to assess if there was a relationship between the clinical and biological variables. METHODS: 20 women with ISCC of the vulva were assessed with pretreatment primary tumour oxygenation with an Eppendorf pO2 probe. Patients underwent standard surgical management. Pathological assessment of the primary and nodal tissues was then performed. Primary tumour specimens were also stained for microvessel density and carbonic anhydrase IX. The relationship between smoking, preoperative Hgb, tumour CAIX expression, MVD, and Eppendorf pO2 measurements vs nodal metastasis and between these clinical and biological variables was assessed. RESULTS: Seven patients had positive lymph nodes, 13 had negative nodes. While neither current smoking status, tumour size, tumour oxygen measurements, MVD and CAIX expression correlated with metastatic nodal disease, a low preoperative Hgb correlated with pathological nodal status (p < 0.027). CONCLUSIONS: Although this analysis failed to demonstrate a strong correlation between various measures of tumour oxygenation with nodal metastasis, it may be due to the small number of patients. Only preoperative anaemia is correlated with nodal metastasis in early ISCC of the vulva.

Aged↗

PubMed2001

Carbonic anhydrase 9 as an endogenous marker for hypoxic cells in cervical cancer.

The presence of radiation-resistant hypoxic cells in some solid tumors is known to predict for relapse after radiotherapy. Use of an endogenous marker of hypoxia would be a convenient alternative to current methods that measure tumor oxygenation, provided the marker could be shown to reliably identify viable, radiation-resistant, hypoxic cells. Carbonic anhydrase 9 (CA9) is a transmembrane protein overexpressed in a wide variety of tumor types and induced by hypoxia. Using a monoclonal antibody and cell sorting, CA9-positive cells in SiHa cervical carcinoma xenografts growing in immunodeficient mice were found to be clonogenic, resistant to killing by ionizing radiation, and preferentially able to bind the hypoxia marker pimonidazole. CA9 and pimonidazole immunostaining were compared in formalin-fixed sections from tumors of 18 patients undergoing treatment for cancer of the cervix. Excellent colocalization was observed, although the area of the tumor section that bound anti-CA9 antibodies represented double the number of cells that bound anti-pimonidazole antibodies. Occasional regions staining with pimonidazole but not CA9 could be indicative of transient changes in tumor perfusion. Results support the hypothesis that CA9 is a useful endogenous marker of tumor hypoxia.

Animals↗

PubMed2001

Expression of hypoxia-inducible cell-surface transmembrane carbonic anhydrases in human cancer.

An acidic extracellular pH is a fundamental property of the malignant phenotype. In von Hippel-Lindau (VHL)-defective tumors the cell surface transmembrane carbonic anhydrase (CA) CA9 and CA12 genes are overexpressed because of the absence of pVHL. We hypothesized that these enzymes might be involved in maintaining the extracellular acidic pH in tumors, thereby providing a conducive environment for tumor growth and spread. Using Northern blot analysis and immunostaining with specific antibodies we analyzed the expression of CA9 and CA12 genes and their products in a large sample of cancer cell lines, fresh and archival tumor specimens, and normal human tissues. Expression was also analyzed in cultured cells under hypoxic conditions. Expression of CA IX and CA XII in normal adult tissues was detected only in highly specialized cells and for most tissues their expression did not overlap. Analysis of RNA samples isolated from 87 cancer cell lines and 18 tumors revealed high-to-moderate levels of expression of CA9 and CA12 in multiple cancers. Immunohistochemistry revealed high-to-moderate expression of these enzymes in various normal tissues and multiple common epithelial tumor types. The immunostaining was seen predominantly on the cell surface membrane. The expression of both genes was markedly induced under hypoxic conditions in tumors and cultured tumor cells. We conclude that the cell surface trans-membrane carbonic anhydrases CA IX and CA XII are overexpressed in many tumors suggesting that this is a common feature of cancer cells that may be required for tumor progression. These enzymes may contribute to the tumor microenvironment by maintaining extracellular acidic pH and helping cancer cells grow and metastasize. Our studies show an important causal link between hypoxia, extracellular acidification, and induction or enhanced expression of these enzymes in human tumors.

Biomarkers, Tumor↗

PubMed2000

Facilitation of recovery from inactivation by external Na+ and location of the activation gate in neuronal Na+ channels.

Fast inactivation of the Na(+) channel presumably is produced by binding of the inactivating peptide (the "hinged lid") to the internal pore mouth of the activated channel. It has been shown that recovery from inactivation in Na(+) channels begins with a delay, which corresponds to deactivation of the channel, and is then followed by an exponential phase, which corresponds to unbinding of the inactivating peptide. We found that the exponential phase is approximately 1.6-fold faster in 150 mm than in 0 mm external Na(+), but the initial delays are the same. External Na(+) also increases the late steady-state Na(+) current during a step depolarization and shifts the inactivation curve accordingly but has no effect on the activation and deactivation kinetics of the current. Quantitative analysis of the data reveals that external Na(+) has the same facilitation effect on the unbinding of the bound inactivating peptide whether the channel is activated or deactivated but has no effect on the other gating processes of the channel. These findings suggest that permeating Na(+) ions directly knock off the bound inactivating peptide and that channel activation or deactivation does not affect the accessibility of the bound inactivation peptide to external Na(+). The activation gate (the key gating change transforming a Na(+)-nonconducting pore into a Na(+)-conducting one) therefore should not be located external to the inactivation gate, which presumably is already located close to the internal end of the pore.

Animals↗

PubMed2000

Expression of MN/CA9 protein in Papanicolaou smears containing atypical glandular cells of undetermined significance is a diagnostic biomarker of cervical dysplasia and neoplasia.

BACKGROUND: Despite the enormous impact that Papanicolaou (Pap) smear screening has had on the incidence of cervical carcinoma in developed countries, there is still an unacceptably high frequency of occurrence of this cancer. In part, this is due to human error associated with cytologic diagnoses of Pap smears. Also, the use of new sampling devices, such as the cytobrush, has increased the complexity of diagnosing benign and neoplastic cervical cytology. This is particularly apparent in the diagnosis of atypical glandular cells of undetermined significance (AGUS). Approximately 40% of AGUS diagnoses have a corresponding significant lesion at biopsy follow-up, and 60% do not. There is clearly a need for an adjunct to cytologic diagnosis that can readily identify AGUS smears that are diagnostic of significant lesions. The authors have identified the MN/CA9 antigen as a strong candidate for an adjunct biomarker. METHODS: A total of 245 Pap smears of all AGUS diagnostic categories with histologic confirmation were studied. The median age of the patients was 39 years. The Bethesda system classification (AGUS-favor reactive, AGUS-not otherwise specified, and AGUS-favor neoplastic) was used. All of the Pap smears were decolorized and immunostained with monoclonal antibody to MN/CA9 antigen by the immunoperoxidase technique. The results of MN/CA9 immunoreactivity were correlated with the histologic data in a semiblinded fashion. RESULTS: The follow-up biopsies showed that a high percentage (70%) of patients had low and high grade cervical intraepithelial neoplasia lesions, respectively (CIN I and CIN II or III). Clinically significant lesions-adenocarcinoma in situ/carcinoma (AIS/CA) and CIN II or III-were found in 50% of the cases. Among these, 11% were AIS/CA. In the three subcategories of AGUS diagnosis, the AGUS-not otherwise specified showed the broadest range of lesions in the follow-up biopsies. Three patterns of MN/CA9 immunoreactivity were observed in the Pap smears: 1) atypical cells, 2) normal endocervical cells only, and 3) all cells negative. All Pap smears that were MN/CA9 positive were histologically confirmed to be clinically significant lesions or CIN I; in addition, there were a very small number (n = 12) of cases of atypia. None of the benign lesions showed MN/CA9 expression in the corresponding Pap smears. Furthermore, the pattern of atypical cell immunostaining identified all cases with significant lesions (AIS/CA and CIN II or III) in the cervices. Conversely, the majority of CIN I cases (82%) and all cases of atypia showed positive immunostaining restricted to normal endocervical cells only. CONCLUSIONS: There is a clear association between MN/CA9 immunostaining of atypical cells and the presence of significant lesions in the cervix. Similarly, there is a clear association between lack of expression of MN/CA9 and the absence of cervical lesions. However, the screen does not allow discrimination between CIN I and atypia. The authors also found that, based on the combined patterns of morphology and immunostaining, they are able to discriminate between AIS and CIN II or III in AGUS Pap smear diagnoses. Thus, expression of the MN/CA9 antigen is indeed a discriminator of significant lesions in AGUS Pap smear diagnoses.

Adult↗

PubMed2000

Development and assessment of a general theory of cervical carcinogenesis utilizing a severe combined immunodeficiency murine-human xenograft model.

OBJECTIVE: Currently, we lack a theoretical explanation for why squamous cell cervical cancer develops predominantly in specific sites (i.e., along the squamocolumnar junction). We therefore implanted human cervical tissues containing the transformation zone in severe combined immunodeficiency (SCID) mice and studied morphology, steroid effects, gene expression, and human papillomavirus (HPV) factors. METHODS: Normal and dysplastic human cervical tissues (3 x 2 mm) were placed subcutaneously in SCID-beige mice and later assessed by in situ hybridization for HPV 16/18 DNA and by immunohistochemistry for expression of CD31, keratin, proliferating-cell nuclear antigen, HPV 16 E6, p53, and Notch-1 (a binary cell fate determination protein). Some normal tissues were implanted with either a 90-day release 1.7-mg 17beta-estradiol pellet or a 5-mg tamoxifen pellet; others were infected prior to implantation with human recombinant adenovirus 5 vector containing a human cytomegalovirus promoter-driven beta-galactosidase gene and later assessed by X-gal staining. RESULTS: Murine and human vessels formed anastomoses by 3 weeks. For at least 11 weeks, normal tissue retained the transformation zone and normal cell-type-specific keratin expression and exhibited normal proliferation; Notch-1 was present only in the basal cell layer. Dysplastic tissues exhibited koilocytosis, increased levels of cellular proliferation, and aberrant keratin, p53, and Notch-1 expression; HPV 16/18 DNA and HPV 16 E6 protein were detected for at least 6 weeks. Squamous metaplasia of normal cervical epithelium resulted from estrogen exposure, and a predominant columnar differentiation pattern was associated with tamoxifen administration. Through stable adenovirus infection, beta-galactosidase was expressed for at least 6 weeks. CONCLUSIONS: This small manipulatable xenograft model maintains normal and dysplastic human cervical epithelium through neovascularization. Neoplastic tissue retains HPV 16/18 DNA and a premalignant phenotype, including elevated levels of cellular proliferation and aberrant keratin, p53, and Notch-1 expression. These attributes constitute essential features of a biologic model through which one may study HPV-mediated human disease and may be superior to cell culture and transgenic murine systems. Furthermore, this may serve as a model for gene therapy. Finally, we suggest that the normal cervical epithelium is maintained through putative interactions between the Notch locus and cell cycle growth regulators such as p53 and pRb. Neoplastic cervical epithelium may arise through disruption of this pathway. This theory may be testable in our animal model.

Animals↗

PubMed2000

Breast cancer, heterocyclic aromatic amines from meat and N-acetyltransferase 2 genotype.

Breast cancer risk has been hypothesized to increase with exposure to heterocyclic aromatic amines (HAAs) formed from cooking meat at high temperature. HAAs require enzymatic activation to bind to DNA and initiate carcinogenesis. N-acetyltransferase 2 (NAT2) enzyme activity may play a role, its rate determined by a polymorphic gene. We examined the effect of NAT2 genetic polymorphisms on breast cancer risk from exposure to meat by cooking method, doneness and estimated HAA [2-amino-1-methyl-6-phenylimidazole[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (DiMeIQx)] intake. Women were recruited with suspicious breast masses and questionnaire data were collected prior to biopsy to blind subjects and interviewers to diagnoses. For 114 cases with breast cancer and 280 controls with benign breast disease, NAT2 genotype was determined using allele-specific PCR amplification to detect slow acetylator mutations. HAAs were estimated from interview data on meat type, cooking method and doneness, combined with a quantitative HAA database. Logistic regression models controlled for known risk factors, first including all controls, then 108 with no or low risk (normal breast or no hyperplasia) and finally 149 with high risk (hyperplasia, atypical hyperplasia, complex fibroadenomas). Meat effects were examined within NAT2 strata to assess interactions. We found no association between NAT2 and breast cancer. These Californian women ate more white than red meat (control median 46 versus 8 g/day). There were no significant associations of breast cancer with red meat for any doneness. White meat was significantly protective (>67 versus <26 g/day, OR 0.46, 95% CI 0.23-0.94, P for trend = 0.02), as was chicken, including well done, pan fried and barbecued chicken. MeIQx and DiMeIQx were not associated with breast cancer. A protective effect of PhIP was confounded after controlling for well done chicken. Results were unchanged using low or high risk controls or dropping 30 in situ cases. There was no interaction between NAT2 and HAAs. These findings do not support a role for HAAs from meat or NAT2 in the etiology of breast cancer. Further research is needed to explain the white meat association.

Adult↗

PubMed2000

Breast cancer, passive and active cigarette smoking and N-acetyltransferase 2 genotype.

The relationship of breast cancer to cigarette smoking is inconsistent in the literature, possibly due in part to heterogeneity in carcinogen metabolism. N-acetyltransferase 2 (NAT2) enzyme activity is believed to play a role in the activation of tobacco smoke carcinogens. We examined the effect of NAT2 genetic polymorphisms on risk of breast cancer from active and passive smoking. Women were recruited from those who had suspicious breast masses detected clinically and/or mammographically. Questionnaire data were collected prior to biopsy diagnosis to blind subjects and interviewers. Histopathology showed 113 cases with mammary carcinoma (30 carcinoma in situ) and 278 controls with benign breast disease. NAT2 genotype was determined using allele-specific polymerase chain reaction amplification to detect slow acetylator mutations. Effects of passive and active tobacco smoke and of NAT2 genotype on breast cancer risk were examined with logistic regression controlling for known risk factors. Models first included all controls, and subsequently 107 with no or low risk (normal breast or no hyperplasia), and finally 148 with high risk (hyperplasia, atypical hyperplasia, complex fibroadenomas). Referents had no active or passive smoke exposure. We found no association between breast cancer risk and NAT2, smoking status (never, former, current), smoking duration, or cigarettes per day. There were no effects of passive exposure among never-smokers. Models were unchanged across control groups. There were no statistical interactions between tobacco smoke exposure and NAT2. The results were similar when restricting the analysis to invasive cancers. These findings do not support the hypothesis that NAT2 is a risk factor for breast cancer or that it alters susceptibility to tobacco smoke.

Adult↗

PubMed2000

Cancer risk estimates for family members of a population-based family registry for breast and ovarian cancer.

Population-based breast and ovarian cancer family registries can facilitate studies to evaluate genetic and environmental factors in the etiology of these malignancies. The purpose of this study is to describe what is, as far as we know, the first population-based breast and ovarian cancer family registry and to estimate breast and ovarian cancer risk in relatives of breast and ovarian cancer probands. Population-based consecutive incident cases of breast and ovarian cancer were invited to participate in the University of California, Irvine breast and ovarian family registry. In this study, we report data on 1567 breast cancer and 328 ovarian cancer probands. The operational components of this family registry include enrollment of probands, family history interviewing, confidentiality, pathology, verification and review, biospecimen bank, statistical/genetic analysis, and special studies on positional cloning of known genes. All of the components are tracked through the University of California, Irvine Genetic Research Information System. In non-Hispanic-white breast cancer probands, relative risk (RR) of breast cancer in mothers and sisters is significantly elevated [RR = 1.7 and 95% confidence interval (CI) = 1.4-2.0 and RR = 2.8 and 95% CI = 2.3-3.3, respectively]. In families of ovarian cancer probands, mothers are at increased risk of ovarian cancer (RR = 4.6; 95% CI, 2.1-8.7). RR of breast cancer in mothers of Hispanic breast cancer probands is significantly elevated (RR = 4.9; 95% CI, 2.6-8.5). No elevation of breast or ovarian cancer risk was observed among relatives of Asian probands. In general, there is a decrease in RR among mothers and sisters with increase in age of onset of probands. In second-degree relatives and first cousins, the breast cancer hazards ratios increase with increase in the number of affected first-degree relatives and decrease with increase in age at onset of the proband.

Adult↗

PubMed1999

Surgical outcome of traumatic intracranial hematoma at a regional hospital in Taiwan.

BACKGROUND: To report the experience in the management of 489 consecutive patients with traumatic intracranial hematoma and determine the prognostic factors. METHODS: All patients were classified into three groups based on the number of operations for each case. A total of 538 operations were performed for evacuation of 720 intracranial hematomas. RESULTS: The most common cause of injury was motor vehicular traffic crashes (68.7%) and most victims were motorcyclists (40.1%). The most common type of lesion was acute epidural hematoma (31.0%). The overall mortality rate was 9.6%, and the complication rate was 11.2%. Follow-up assessment of 480 patients revealed that 270 (56.2%) patients made a good recovery, 99 (20.6%) were moderately disabled, 32 (6.7%) were severely disabled, 21 (4.4%) were vegetative, and 58 (12.1%) had died. CONCLUSION: The surgical outcome was significantly correlated with the score of the Glasgow Coma Scale, pupillary reactivity, number of operations, and type of lesion.

Adolescent↗

PubMed1999

Immunohistochemical analysis, human papillomavirus DNA detection, hormonal manipulation, and exogenous gene expression of normal and dysplastic human cervical epithelium in severe combined immunodeficiency mice.

The cervical squamocolumnar junction of normal and dysplastic human xenografts was maintained in SCID-beige mice. Dysplastic tissue maintained a dysplastic morphology, irregular pattern of keratin expression, elevated levels of cellular proliferation, and human papillomavirus type 16 and/or type 18 DNA. Hyperplastic changes of normal xenografts occurred via high-dose estrogen exposure, and through recombinant adenovirus infection, the introduction and stable expression of an exogenous gene was accomplished.

Adenoviridae↗

PubMed1999

Randomized comparison of fluorouracil plus cisplatin versus hydroxyurea as an adjunct to radiation therapy in stage IIB-IVA carcinoma of the cervix with negative para-aortic lymph nodes: a Gynecologic Oncology Group and Southwest Oncology Group study.

PURPOSE: In 1986, a protocol comparing primary radiation therapy (RT) plus hydroxyurea (HU) to irradiation plus fluorouracil (5-FU) and cisplatin (CF) was activated by the Gynecologic Oncology Group (GOG) for the treatment of patients with locally advanced cervical carcinoma. The goals were to determine the superior chemoradiation regimen and to quantitate the relative toxicities. METHODS: All patients had biopsy-proven invasive squamous cell carcinoma, adenocarcinoma, or adenosquamous carcinoma of the uterine cervix. Patients underwent standard clinical staging studies and their tumors were found to be International Federation of Gynaecology and Obstetrics stages IIB, III, or IVA. Negative cytologic washings and para-aortic lymph nodes were required for entry. Patients were randomized to receive either standard whole pelvic RT with concurrent 5-FU infusion and bolus CF or the same RT plus oral HU. RESULTS: Of 388 randomized patients, 368 were eligible; 177 were randomized to CF and 191 to HU. Adverse effects were predominantly hematologic or gastrointestinal in both regimens. Severe or life-threatening leukopenia was more common in the HU group (24%) than in the CF group (4%). The difference in progression-free survival (PFS) was statistically significant in favor of the CF group (P = .033). The sites of progression in the two treatment groups were not substantially different. Survival was significantly better for the patients randomized to CF (P = .018). CONCLUSION: This study demonstrates that for patients with locally advanced carcinoma of the cervix, the combination of 5-FU and CF with RT offers patients better PFS and overall survival than HU, and with manageable toxicity.

Adenocarcinoma↗

PubMed1999

Intracerebral hemorrhage caused by cerebral amyloid angiopathy: a case report.

Cerebral amyloid angiopathy (CAA) accounts for approximately 10% of spontaneous intracerebral hemorrhages (ICH), and typically occurs in the cortex and subcortical white matter. It is characterized by the deposition of amyloid fibrils in the leptomeningeal, cortical and subcortical arteries. Pathologically, amyloid is stained pink with Congo red and shows yellow-green birefringence when viewed under polarized light. Although there have been many reports of CAA in the literature, it has rarely been described in Taiwan. This is the report of a case of a 75-year-old man with ICH caused by CAA. The postoperative course was uneventful. The incidence of this disease increases with age. The authors, therefore, suggest conducting a brain biopsy and special stain for CAA in each operative case of spontaneous ICH, especially in the elderly.

Aged↗

PubMed1998

Loss of the tight junction MAGUK ZO-1 in breast cancer: relationship to glandular differentiation and loss of heterozygosity.

Membrane-associated guanylate kinase homologs (MAGUKs) may play a role in cellular functions preventing tumorigenesis as indicated by the neoplastic phenotype caused by genetic loss of the MAGUK Dlg in Drosophila. To test this possibility, we examined the expression and subcellular localization of the tight junction MAGUK ZO-1, as well as the cell adhesion molecule E-cadherin, in paraffin-embedded breast cancer samples, using immunohistochemistry and confocal microscopy. As expected, normal tissue showed intense staining for ZO-1 at the position of the epithelial tight junctions, but this staining was reduced or lost in 69% of breast cancers analyzed (n = 48). In infiltrating ductal carcinomas (n = 38) there was a reduction in staining in 42% of well differentiated, in 83% of moderately differentiated and 93% of poorly differentiated tumors. ZO-1 staining was positively correlated with tumor differentiation (P = .011) and more specifically with the glandular differentiation of tumors (P = .0019). Reduction in ZO-1 staining was strongly correlated with reduced E-cadherin staining (P = 4.9 x 10(-5)). The results suggest that down-regulation of ZO-1 expression and its failure to accumulate at cell junctions may be causally related to cancer progression. To detect loss of heterozygosity, the ZO-1 gene tjp-1 was mapped relative to other markers in 15q13 and polymorphic markers flanking tjp-1 were identified. The marker D15S1019 showed loss of heterozygosity in 23% of informative tumors (n = 13). Loss of a tjp-1-linked marker suggests that genetic loss may, in some cases, be responsible for the reduction in ZO-1 expression in breast cancer.

Breast Neoplasms↗

PubMed1997

Genetic alterations accumulate during cervical tumorigenesis and indicate a common origin for multifocal lesions.

Carcinomas of the uterine cervix are thought to arise from preinvasive dysplastic lesions, termed cervical intraepithelial neoplasias (CIN), grades I-III. Patients may present clinically with two or more distinct lesions of differing histological severity; however, the genesis of these multifocal lesions is unknown. Despite infection with high-risk human papilloma virus subtypes, which is a major etiological factor in disease pathogenesis, only a small and unpredictable number of dysplastic lesions progress to invasive cancer. Several lines of evidence suggest that additional somatic events, such as tumor suppressor gene inactivation, are required for malignant transformation. In support of this, loss of heterozygosity (LOH) analyses of invasive cervical carcinomas have identified several chromosomal arms likely to harbor tumor suppressor genes, of which regions on 3p, 4p, 4q, and 11q have been validated extensively. To evaluate the potential role of tumor suppressor gene inactivation in dysplastic progression, loci distributed on these four chromosomal regions were assessed for LOH in 42 CIN lesions of varying histological grade obtained from 17 patients. Analysis of at least 16 microsatellite loci in each lesion revealed allelic losses involving one or more of these chromosomal regions in 0% of CIN I lesions; 25% of CIN II lesions; and 88% of CIN III lesions, with 41% of CIN III lesions exhibiting LOH for three or more chromosomal regions. In addition, where LOH was scored for the same locus at a particular chromosomal region in all of the multiple lesions from a single patient, the same allele was lost at each locus, without exception. Statistical analysis of these allele-specific losses strongly suggests that topologically distinct lesions are related and likely arise from a common precursor cell.

Cell Transformation, Neoplastic↗

PubMed1997

Identification of the MN/CA9 protein as a reliable diagnostic biomarker of clear cell carcinoma of the kidney.

The MN/CA9 protein is a tumor-associated antigen that has been shown to have diagnostic utility in identifying cervical dysplasia and carcinoma. MN/CA9 expression is limited to very few normal tissues. We have now extended those observations to further investigate expression of the MN/CA9 protein in histological sections and fine-needle aspiration biopsy smears of normal kidney, benign renal cell lesions, all categories of renal cell carcinomas (clear/granular/spindle cell, chromophilic cell, chromophobic cell, and collecting duct cell RCCs), metastatic RCCs, and non-renal cell clear cell adenocarcinomas. We have found that high levels of MN/CA9 expression is seen in all primary RCCs, cystic RCCs, and metastatic RCCs, with the exception of two cases of the chromophobe cell type, which were MN/CA9 negative. Identical MN/CA9 immunostaining was also observed in the aspiration cytological smears. In contrast, all benign lesions, including pyelonephritis, renal cysts, adenomas, oncocytomas, and normal kidney, did not express the MN/CA9 protein. Thus, we conclude that MN/CA9 protein expression could serve as a valuable adjunct to the cytological and histological diagnosis of benign renal cysts versus cystic RCC, adenoma versus RCC, and oncocytoma versus granular cell RCC. Diffuse membraneous staining of all RCCs (with the exception of chromophobic cell RCC) suggests that MN/CA9 protein expression might have an important clinical utility in the early detection and treatment of RCC. Absence of MN/CA9 expression in non-renal cell clear cell adenocarcinoma also indicates that MN/CA9 protein expression may be used as a differential diagnostic biomarker of metastatic clear cell RCC.

Adult↗