Biomedical subjects

Christopher Umbricht

Publications and source records attributed to Christopher Umbricht.

4 recordsLinked to original sources

PubMed2005

A six-gene model for differentiating benign from malignant thyroid tumors on the basis of gene expression.

BACKGROUND: Thyroid nodules are common; fine-needle aspirations commonly are read as indeterminate, necessitating surgery to exclude carcinoma. We developed a 6-gene array-based predictor model to diagnose benign versus malignant thyroid lesions. In this study, we verified whether quantitative reverse transcription-polymerase chain reaction (qRT-PCR) using this model reliably can differentiate benign from malignant thyroid nodules. METHODS: Molecular profiles of benign (follicular adenomas, hyperplastic nodules) and malignant tumors (papillary thyroid carcinomas, follicular variants of papillary thyroid carcinomas) were analyzed using qRT-PCR from our 6-gene model (kit, Hs.296031, Hs.24183, LSM7, SYNGR2, C21orf4). The gold standard was standard pathologic criteria. A diagnosis-predictor model was built by using the training samples and was then used to predict the class of 10 additional samples analyzed as unknowns. RESULTS: Our predictor model using 47 training samples correctly predicted 9/10 unknowns. One sample diagnosed as benign by standard histologic criteria was diagnosed as malignant by our model (sensitivity 75%; specificity, 100%; positive predictive value, 100%; negative predictive value, 85.7%). CONCLUSIONS: Molecular diagnosis with our 6-gene model can differentiate between benign and malignant thyroid tumors with high sensitivity and specificity. In combination, these genetic markers may be a reliable test to preoperatively diagnose the malignant potential of thyroid nodules.

Adenoma↗

PubMed2004

Using gene expression profiling to differentiate benign versus malignant thyroid tumors.

DNA microarrays allow quick and complete evaluation of a cell's transcriptional activity. Expression genomics is very powerful in that it can generate expression data for a large number of genes simultaneously across multiple samples. In cancer research, an intriguing application of expression arrays includes assessing the molecular components of the neoplastic process and utilizing the data for cancer classification (Miller LD, et al. Cancer Cell 2002;2:353-61). Classification of human cancers into distinct groups based on their molecular profile rather than their histological appearance may prove to be more relevant to specific cancer diagnoses and cancer treatment regimes. Several attempts to formulate a consensus about classification and treatment of thyroid carcinoma based on standard histopathological analysis have resulted in published guidelines for diagnosis and initial disease management (Sherman SI. Lancet 2003;361:501-11). In the past few decades, no improvement has been made in the differential diagnosis of thyroid tumors by fine needle aspiration biopsy, specifically suspicious or indeterminate thyroid lesions, suggesting that a new approach to this should be explored. Therefore, in this study, we developed a gene expression approach to diagnose benign versus malignant thyroid lesions in 73 patients with thyroid tumors. We successfully built a 10 and 6 gene model able to differentiate benign versus malignant thyroid tumors. Our results support the premise that a molecular classification system for thyroid tumors is possible, and this in turn may provide a more accurate diagnostic tool for the clinician managing patients with suspicious thyroid lesions.

Diagnosis, Differential↗

PubMed2003

Molecular pathogenesis of thyroid cancer.

A number of molecular abnormalities have been described in association with the progression from normal thyroid tissue to benign adenomas to well-differentiated and finally anaplastic epithelial thyroid cancer. These include upregulation of proliferative factors, such as growth hormones and oncogenes, downregulation of apoptotic and cell-cycle inhibitory factors, such as tumor suppressors, disruption of normal cell-to-cell interactions, and cellular immortalization. The progression model for thyroid carcinoma has not been proven, but evidence suggests that an evolutionary molecular process is involved, especially in the development of follicular thyroid cancers for which there are distinct intermediate phenotypes. We present a comprehensive evaluation of factors involved in thyroid tumorigenesis and attempt to describe preliminary attributes of a progression model. The organization of this model should also provide a template for the incorporation of new information as it is derived from large-scale genomic studies.

Apoptosis↗

PubMedDate not supplied

Beyond the suspicious thyroid fine needle aspirate. A review.

Fine needle aspiration (FNA) is currently the best diagnostic tool for thyroid nodules. However, the cytologic category of indeterminate or suspicious lesion, which is found in 10-15% of cases, remains a challenge. Since neither clinical presentation nor intraoperative frozen section is often helpful in differentiating these lesions and since surgical procedures for benign and malignant lesions differ, there is a clear need to develop ancillary tests. In this review we identify 12 potential markers of thyroid malignancy that have been examined in thyroid cytologic samples. Although many of these markers hold promise as adjuncts to FNA cytology, multicenter studies have often shown limitations in the predictive value of these assays due to lack of specificity, sensitivity or both. The recent development, however, of tissue microarray techniques to validate promising new markers suggests that improvements in the approach to indeterminate thyroid FNA samples may soon be at hand. This review presents a summary of the issues facing the development of a clinically useful diagnostic test in the differential diagnosis of thyroid nodules.

Biomarkers, Tumor↗