Biomedical subjects

Ie-Ming Shih

Publications and source records attributed to Ie-Ming Shih.

17 recordsLinked to original sources

PubMed2026

The Pathogenesis of Epithelial Ovarian Cancer.

Epithelial ovarian cancer is not a single disease but a group of biologically distinct malignancies that include serous (high-grade and low-grade), endometrioid, clear cell, and mucinous carcinomas, along with other rare subtypes. Integrating clinicopathological analyses, genomic and multiomic data, and experimental investigations in model systems has revealed the pathogenesis of the various histologic subtypes. A unique feature of epithelial ovarian cancer is that most of these tumors are now recognized to arise not from ovarian tissue but from the fallopian tube or endometrium, the latter in the context of ovarian endometriosis. Studies of precursor lesions have revealed complex evolutionary trajectories and the earliest molecular events in their development. Recent single-cell and spatial technologies further elucidate the roles of intratumoral heterogeneity and the tumor microenvironment in disease progression. This review summarizes these advances from the perspective of tissue of origin and highlights their implications for prevention, early detection, and therapeutic development.

Journal Article↗

PubMed2003

Increased plasma DNA integrity in cancer patients.

Tumor-released DNA in blood represents a promising biomarker for cancer detection. It has been postulated that tumor necrosis causes release of DNA of varying sizes, which contrasts apoptosis in normal tissue that releases smaller and more uniform DNA fragments. To test the hypothesis that increased DNA integrity, i.e., a longer DNA strand, is a tumor-associated marker in plasma, we determined the genomic DNA integrity index in plasma DNA using real-time PCR assays. A DNA integrity index and DNA concentration in plasma were determined in 61 patients with gynecological and breast cancers and 65 female patients without neoplastic diseases. We found that the area under the receiver-operating characteristic curve for DNA integrity index was 0.911 for cancer versus nonneoplastic patients. Given 100% specificity, the highest sensitivity achieved in detecting the cancer group was 62% (95% confidence interval = 0.50-0.74) at the index cutoff of 0.59. Fifty percent of stage I cancers had a DNA integrity index above this cutoff. All 11 patients with benign adnexal masses that clinically can be confused with malignant gynecological neoplasms demonstrated DNA integrity index < 0.59. Our findings suggest that increased DNA integrity in plasma DNA is associated with cancer, and measurement of DNA integrity may provide a simple and inexpensive measure for cancer detection.

Case-Control Studies↗

PubMed2003

Identifying tumor origin using a gene expression-based classification map.

Identifying the primary site in cases of metastatic carcinoma of unknown origin has profound clinical importance in managing cancer patients. Although transcriptional profiling promises molecular solutions to this clinical challenge, simpler and more reliable methods for this purpose are needed. A training set of 11 serial analysis of gene expression (SAGE) libraries was analyzed using a combination of supervised and unsupervised computational methods to select a small group of candidate genes with maximal power to discriminate carcinomas of different tissue origins. Quantitative real-time PCR was used to measure their expression levels in an independent validation set of 62 samples of ovarian, breast, colon, and pancreatic adenocarcinomas and normal ovarian surface epithelial controls. The diagnostic power of this set of genes was evaluated using unsupervised cluster analysis methods. From the training set of 21,321 unique SAGE transcript tags derived from 11 libraries, five genes were identified with expression patterns that distinguished four types of adenocarcinomas. Quantitative real-time PCR expression data obtained from the validation set clustered tumor samples in an unsupervised manner, generating a self-organized map with distinctive tumor site-specific domains. Eighty-one percent (50 of 62) of the carcinomas were correctly allocated in their corresponding diagnostic regions. Metastases clustered tightly with their corresponding primary tumors. A classification map diagnostic of tumor types was generated based on expression patterns of five genes selected from the SAGE database. This expression map analysis may provide a reliable and practical approach to determine tumor type in cases of metastatic carcinoma of clinically unknown origin.

Adenocarcinoma↗

PubMed2003

Mutations in BRAF and KRAS characterize the development of low-grade ovarian serous carcinoma.

Activating mutations in KRAS and in one of its downstream mediators, BRAF, have been identified in a variety of human cancers. To determine the role of mutations in BRAF and KRAS in ovarian carcinoma, we analyzed both genes for three common mutations (at codon 599 of BRAF and codons 12 and 13 of KRAS). Mutations in either codon 599 of BRAF or codons 12 and 13 of KRAS occurred in 15 of 22 (68%) invasive micropapillary serous carcinomas (MPSCs; low-grade tumors) and in 31 of 51 (61%) serous borderline tumors (precursor lesions to invasive MPSCs). None of the tumors contained a mutation in both BRAF and KRAS. In contrast, none of the 72 conventional aggressive high-grade serous carcinomas analyzed contained the BRAF codon 599 mutation or either of the two KRAS mutations. The apparent restriction of these BRAF and KRAS mutations to low-grade serous ovarian carcinoma and its precursors suggests that low-grade and high-grade ovarian serous carcinomas develop through independent pathways.

Codon↗

PubMed2003

Mel-CAM (CD146) expression in parotid mucoepidermoid carcinoma.

Mel-CAM (CD146) is a cell-cell adhesion protein found in normal and tumoral tissues. The aim of this study was to analyse Mel-CAM expression in mucoepidermoid carcinoma (MEC), and assess its importance in prognosis and its utility in differentiating high-grade MEC from squamous cell carcinoma (SCC). Immunohistochemical expression of Mel-CAM in 41 parotid MEC was correlated with clinical parameters. Ten cases of oral cavity SCC were included for comparison. Mel-CAM expression was found in 92.7% of the MEC but was not expressed by the SCC. Mel-CAM expression was greater in intermediate/high grade tumors, was weaker in patients that presented local recurrence, regional and distant metastasis, but no correlation between Mel-CAM and clinical stage and survival of the patients was found. Decreased Mel-CAM expression can impair cellular contact properties, facilitating growth, cell spreading and metastasis in MEC. Mel-CAM can also be useful in differentiating high grade MEC from SCC.

Adolescent↗

PubMed2003

Mutational analysis of K-ras segregates ovarian serous carcinomas into two types: invasive MPSC (low-grade tumor) and conventional serous carcinoma (high-grade tumor).

We previously proposed a dualistic model for ovarian serous carcinogenesis. One pathway involves the stepwise development of invasive micropapillary serous carcinoma (MPSC) from serous borderline tumor (atypical proliferative serous tumor) to noninvasive and then invasive MPSC. The carcinomas that develop in this fashion are characterized by low-grade nuclei and frequent K-ras mutations. They generally pursue an indolent course. In the other pathway conventional serous carcinoma (CSC) develops from the ovarian surface epithelium without what appears to be intermediate stages. These tumors display high-grade nuclei, wild-type K-ras, and are very aggressive. Some of these CSCs display micropapillary architecture and simulate invasive MPSCs. This raises the possibility that these CSCs develop from an invasive MPSC. To address this question we reviewed 31 moderately and poorly differentiated CSCs and identified 7 with morphological features of invasive MPSC. These seven tumors exhibited micropapillary architecture in at least 25% of the tumor but contained high-grade nuclei. The 31 tumors were assessed for K-ras mutations using digital polymerase chain reaction-based analysis. Despite their micropapillary architecture, all 7 CSCs with micropapillary features contained wild-type K-ras as did the other 24 pure CSCs. The results indicate that CSCs with micropapillary features are not derived from invasive MPSCs. The molecular findings also support the view that ovarian serous carcinomas should be graded as low- and high-grade tumors.

Cystadenocarcinoma, Serous↗

PubMed2002

The role of chromosomal instability in tumor initiation.

Chromosomal instability (CIN) is a defining characteristic of most human cancers. Mutation of CIN genes increases the probability that whole chromosomes or large fractions of chromosomes are gained or lost during cell division. The consequence of CIN is an imbalance in the number of chromosomes per cell (aneuploidy) and an enhanced rate of loss of heterozygosity. A major question of cancer genetics is to what extent CIN, or any genetic instability, is an early event and consequently a driving force for tumor progression. In this article, we develop a mathematical framework for studying the effect of CIN on the somatic evolution of cancer. Specifically, we calculate the conditions for CIN to initiate the process of colorectal tumorigenesis before the inactivation of tumor suppressor genes.

Animals↗

PubMed2002

Assessment of plasma DNA levels, allelic imbalance, and CA 125 as diagnostic tests for cancer.

BACKGROUND: Allelic imbalance (AI), the loss or gain of chromosomal regions, is found in many cancers. AI can be detected in genomic tumor DNA released into the blood after necrosis or apoptosis. We evaluated plasma DNA concentration, allelic status in plasma DNA, and serum CA 125 level as screening tests for ovarian and other cancers. METHODS: Plasma samples were obtained from 330 women (44 normal healthy control individuals, 122 patients with various cancers, and 164 control patients with non-neoplastic diseases). Plasma DNA concentration was determined in all samples. Allelic status was determined by digital single nucleotide polymorphism (SNP) analysis with eight SNP markers in plasma DNA from 54 patients with ovarian cancer and 31 control patients. CA 125 was determined in 63 samples. Receiver-operating characteristic (ROC) curves were plotted, and the areas under the ROC curves--a measure of the overall ability of a diagnostic test with multiple cutoffs to distinguish between diseased and nondiseased individuals--were determined. RESULTS: The area under the ROC curve for plasma DNA concentration was 0.90 for patients with neoplastic disease versus healthy control individuals and 0.74 for patients with neoplastic diseases versus control patients with non-neoplastic diseases. For control subjects given a specificity of 100% (95% confidence interval [CI] = 92% to 100%), the highest sensitivity achieved was 57% (95% CI = 49% to 67%). AI in at least one SNP was found in 87% (95% CI = 60% to 98%) of patients with stage I/II ovarian cancer and 95% (95% CI = 83% to 99%) of patients with stage III/IV ovarian cancer, but AI was not found in 31 patients with non-neoplastic diseases (specificity = 100%, 95% CI = 89% to 100%). The area under the ROC curve assessing AI was 0.95. Combining the serum CA 125 level with the plasma DNA concentration increased the area under the ROC curve from 0.78 (CA 125 alone) to 0.84. CONCLUSION: Plasma DNA concentration may not be sensitive or specific enough for cancer screening or diagnosis, even when combined with CA 125. AI was detected with high specificity in plasma DNA from patients with ovarian cancer and should be studied further as a screening tool.

Adult↗

PubMed2002

APC/CTNNB1 (beta-catenin) pathway alterations in human prostate cancers.

Genetic alterations serve as beacons for the involvement of specific pathways in tumorigenesis. It was previously shown that 5% of prostate tumors harbor CTNNB1 mutations, suggesting that this tumor type may involve a deregulated APC/CTNNB1 pathway. To explore this possibility further, we searched for mutations in genes implicated in this pathway in 22 samples that included cell lines, xenografts, and primary tumors. We identified seven alterations: two in CTNNB1, three in APC, and two in hTRCP1 (also known as BTRC) which controls the degradation of CTNNB1. Alterations in the CTNNB1 regulatory domain, APC, and hTRCP1 were mutually exclusive, consistent with their equivalent effects on CTNNB1 stability. These results suggest that CTNNB1 signaling plays a critical role in the development of a significant fraction of prostate cancers. Moreover, they provide the first evidence that hTRCP1 plays a role in human neoplasia.

Animals↗

PubMed2002

Diverse tumorigenic pathways in ovarian serous carcinoma.

This study was undertaken to analyze genetic alterations in 108 sporadic serous ovarian neoplasms to elucidate ovarian serous carcinogenesis. Our results demonstrate that K-ras mutations occur in approximately 50% of serous borderline tumors (SBTs), non-invasive micropapillary serous carcinomas (MPSCs), and invasive micropapillary serous carcinomas, which represent a morphological continuum of tumor progression. Moreover, progressive increase in the degree of allelic imbalance of chromosomes 1p, 5q, 8p, 18q, 22q, and Xp was observed comparing serous borderline tumors to noninvasive and invasive micropapillary serous carcinomas. In contrast, high-grade (conventional serous carcinoma) tumors contained wild-type K-ras in all 23 cases studied and a high frequency of allelic imbalance even in small (early) primary tumors similar to that found in advanced stage tumors. Based on these findings, we propose a dualistic model for ovarian serous carcinogenesis. One pathway involves a stepwise progression from SBT to noninvasive and then invasive MPSC. The other pathway is characterized by rapid progression from the ovarian surface epithelium or inclusion cysts to a conventional (high-grade) serous carcinoma.

Allelic Imbalance↗

PubMed2002

Molecular genetic analysis of placental site trophoblastic tumors and epithelioid trophoblastic tumors confirms their trophoblastic origin.

Trophoblastic tumors represent a unique group of human neoplasms because they are derived from fetal tissue. Except for choriocarcinoma, the neoplasms that develop from human trophoblast are poorly characterized. Placental site trophoblastic tumors and epithelioid trophoblastic tumors are thought to arise from intermediate (extravillous) trophoblasts based on histopathological studies, but direct molecular evidence of a trophoblastic origin has not been established. In this study, we performed molecular analysis in an attempt to confirm their presumable trophoblastic origin. We demonstrated that such tumors contain a Y-chromosomal locus and/or new (paternal) alleles not present in adjacent normal uterine tissue in all 31 informative cases. Loss of heterozygosity was found in 60% of tumors and all 42 tumors assessed contained wild-type K-ras. All of the trophoblastic tumors were heterozygous in at least 1 of 10 single-nucleotide polymorphism markers studied in contrast to homozygosity in all 10 single-nucleotide polymorphism markers in most complete hydatidiform moles indicating that these tumors are not related to complete hydatidiform moles. This study provides the first molecular evidence that placental site trophoblastic tumors and epithelioid trophoblastic tumors are of fetal (trophoblastic) origin.

Embryonal Carcinoma Stem Cells↗

PubMed2002

The Role of E-cadherin in the Motility and Invasion of Implantation Site Intermediate Trophoblast.

During early pregnancy, intermediate (extravillous) trophoblast infiltrates the basal plate and invades the spiral arteries, a physiological process required to establish the maternal-fetal circulation. Immunostaining studies have shown that differentiation of trophoblast into this invasive subpopulation is associated with down-regulation of E-cadherin expression. To study the function of E-cadherin in trophoblast in vitro, we restored E-cadherin expression in an E-cadherin negative human implantation site intermediate trophoblastic cell line, IST-1, using a recombinant adenovirus, E-cad/Ad5 which constitutively expresses E-cadherin. In contrast to the control IST-1 cells which were individual and pleomorphic in shape, E-cad/Ad5 transduced cells were cohesive, uniform, and round. The motility and invasiveness of E-cad/Ad5 transduced IST-1 cells, as compared with the control cells, was significantly reduced. These effects were contact-dependent and were attenuated by a function-perturbing anti-E-cadherin antibody. In conclusion, our results indicate that expression of E-cadherin in IST-1 cells results in a contact-mediated inhibition of motility and invasion and suggest an important role for E-cadherin down-regulation in the intermediate trophoblast during implantation.

Adenoviridae↗

PubMed2002

HLA-G immunoreactivity is specific for intermediate trophoblast in gestational trophoblastic disease and can serve as a useful marker in differential diagnosis.

HLA-G is a nonclassical MHC class I antigen that has been shown to be a specific marker for normal intermediate trophoblast (IT). In this study HLA-G immunoreactivity assessed with an HLA-G specific antibody (4H84) was detected in all 14 cases of choriocarcinoma, 14 placental site trophoblastic tumors, 13 epithelioid trophoblastic tumors, 16 placental site nodules, and nine exaggerated placental sites. In contrast, HLA-G immunoreactivity was not detected in 34 nontrophoblastic uterine neoplasms. HLA-G immunoreactivity was present in all the IT cells of exaggerated placental sites and placental site trophoblastic tumors and in 70-100% of IT cells in placental site nodules and epithelioid trophoblastic tumors. The pattern of distribution of HLA-G in different subpopulations of IT confirms the relationship of various trophoblastic lesions to different types of IT (exaggerated placental site and placental site trophoblastic tumor to implantation site IT and placental site nodule and epithelioid trophoblastic tumor to chorionic-type IT) and suggests that choriocarcinoma is related to villous-type IT because the majority of mononucleate cells in this neoplasm were HLA-G immunoreactive. In conclusion, HLA-G immunoreactivity appears to be specific for IT in gestational trophoblastic disease and can serve as a useful marker in the differential diagnosis of these lesions.

Antibodies↗

PubMed2002

Molecular basis of gestational trophoblastic diseases.

Gestational trophoblastic disease (GTD) encompasses a diverse group of lesions with specific pathogenesis, morphological characteristics and clinical features. The modified World Health Organization-classification of GTD includes complete and partial hydatidiform mole, invasive mole, choriocarcinoma, placental site trophoblastic tumor, epithelioid trophoblastic tumor, exaggerated placental site, and placental site nodule. The various forms of gestational trophoblastic disease can be defined and related to discrete pathologic aberrations occurring at different stages of trophoblastic differentiation. Some of these lesions are true neoplasms, whereas others represent abnormally formed placentas with a predisposition for neoplastic transformation of the trophoblast. Except hydatidiform moles in which the cytogenetic studies have been extensively reported, the pathogenesis of other trophoblastic lesions is poorly understood. Recent studies have shed light on the molecular mechanisms of trophoblastic function, especially as it relates to trophoblastic disease. This review will focus on these advances with special emphasis on the pathogenesis of each specific form of GTD. In addition, the morphology and clinical behavior of each of these entities will be briefly discussed.

Blastocyst↗

PubMed2002

Proteomic approaches to tumor marker discovery.

CONTEXT: Current tumor markers for ovarian cancer still lack adequate sensitivity and specificity to be applicable in large populations. High-throughput proteomic profiling and bioinformatics tools allow for the rapid screening of a large number of potential biomarkers in serum, plasma, or other body fluids. OBJECTIVE: To determine whether protein profiles of plasma can be used to identify potential biomarkers that improve the detection of ovarian cancer. DESIGN: We analyzed plasma samples that had been collected between 1998 and 2001 from patients with sporadic ovarian serous neoplasms before tumor resection at various International Federation of Gynecology and Obstetrics stages (stage I [n = 11], stage II [n = 3], and stage III [n = 29]) and from women without known neoplastic disease (n = 38) using proteomic profiling and bioinformatics. We compared results between the patients with and without cancer and evaluated their discriminatory performance against that of the cancer antigen 125 (CA125) tumor marker. RESULTS: We selected 7 biomarkers based on their collective contribution to the separation of the 2 patient groups. Among them, we further purified and subsequently identified 3 biomarkers. Individually, the biomarkers did not perform better than CA125. However, a combination of 4 of the biomarkers significantly improved performance (P < or =.001). The new biomarkers were complementary to CA125. At a fixed specificity of 94%, an index combining 2 of the biomarkers and CA125 achieves a sensitivity of 94% (95% confidence interval, 85%-100.0%) in contrast to a sensitivity of 81% (95% confidence interval, 68%-95%) for CA125 alone. CONCLUSIONS: The combined use of bioinformatics tools and proteomic profiling provides an effective approach to screen for potential tumor markers. Comparison of plasma profiles from patients with and without known ovarian cancer uncovered a panel of potential biomarkers for detection of ovarian cancer with discriminatory power complementary to that of CA125. Additional studies are required to further validate these biomarkers.

Adult↗

PubMed2002

Detection of allelic imbalance in ascitic supernatant by digital single nucleotide polymorphism analysis.

PURPOSE: Cytological examination of ascitic fluid is critical for clinical management of patients with peritoneal or pelvic diseases. Such morphological examination can only achieve a sensitivity of <62%, and thus a molecular test that is able to distinguish benign versus malignant ascites could be clinically useful. In this study we determined the presence of allelic imbalance (AI) in tumor-released DNA in ascitic supernatant by directly counting the alleles using a newly developed technology, digital single nucleotide polymorphism (SNP) analysis. EXPERIMENTAL DESIGN: Allelic status was assessed using a total of seven SNP markers that commonly demonstrated AI in ovarian, colorectal, and pancreatic cancers. RESULTS: With digital SNP analysis, AI in at least one SNP marker was found in 19 of 20 (95%) ascitic fluid DNA samples obtained from patients with cytologically proven carcinomas in ascitic fluid. In contrast, AI was detected in only 1 of 20 patients with negative cytology. This latter patient with AI in her ascites had known stage III ovarian carcinoma at the time of cytology sampling. The ascitic specimen of this patient demonstrated the presence of carcinoma cells in culture with an identical AI pattern found in the ascitic supernatant and surgical specimen. CONCLUSIONS: These findings suggest that detection of AI using digital SNP analysis can be a useful adjunct for the detection of ovarian and other types of cancer in ascitic fluid.

Alleles↗

PubMed2002

Genotype analysis using human hair shaft.

Analysis of genotypes for genetic predisposition of diseases has profound and widespread clinical application and has become a fundamental tool in the study of molecular epidemiology. In this study, we report a convenient and completely noninvasive approach to perform genotyping using terminal cephalic hair shaft. The average and median DNA amounts purified from the hair shaft are 112 +/- 180 (1 SD) pg/mg and 66 pg/mg of hair shaft, respectively. Using hybridization with molecular beacons that can reliably distinguish single nucleotide polymorphisms at different alleles, we are able to analyze the genotypes of APO-E and G-protein beta3 (GNB3) subunit C825T loci in DNA samples obtained from hair shaft in a high throughput format. The amount of DNA obtained from 20 mg of hair shaft is sufficient for multiple independent genotyping assays. These findings demonstrate that terminal hair shaft provides a convenient and reliable genomic DNA source for an analysis of genotypes.

DNA↗