PubMed Health⌕ Search

Biomedical subjects

Louis S Liou

Publications and source records attributed to Louis S Liou.

12 recordsLinked to original sources
PubMed2007

Reflex UroVysion testing of bladder cancer surveillance patients with equivocal or negative urine cytology: a prospective study with focus on the natural history of anticipatory positive findings.

A proportion of patients under surveillance for recurrent bladder carcinoma with no immediate evidence of bladder tumor recurrence have positive multitarget fluorescence in situ hybridization (FISH; UroVysion, Vysis, Downers Grove, IL) results. The course of these "anticipatory positive" cases and the time to bladder tumor recurrence remains unknown. We followed up 250 patients with urine cytologic results, concurrent multitarget FISH, and cystoscopic examination for recurrent urothelial carcinoma. Of 81 cases (32.4%) with FISH-positive results, tumor recurrence developed in 60 (74.0%). Of 169 (67.6%) FISH-negative cases, recurrent urothelial carcinoma developed in 22 (13.0%). Of 211 patients (84.4%) with negative cystoscopic examination results, 56 (26.5%) had positive FISH results, and in 35 (62.5%) of these patients, recurrent urothelial carcinoma developed. Approximately 27% of patients under bladder carcinoma surveillance without immediate evidence of tumor recurrence will have a positive FISH result, defining the anticipatory positive subset. In about 65% of this anticipatory positive group, recurrent bladder urothelial carcinoma developed within 29 months.

Cystoscopy↗
PubMed2006

Urothelial cancer biomarkers for detection and surveillance.

Cancer is a complex process, and the US cancer-specific death rate has not changed in the last 50 years. Cure of the disease usually results from early diagnosis and treatment. Urothelial carcinoma (UC) has the highest recurrence rate of any cancer and is the second most common cancer of the genitourinary tract. It usually does not present at a metastatic stage, but only 50% of patients treated with cystectomy survive > or =5 years. There is a UC surveillance protocol, which includes cystoscopy, imaging, and cytology, to detect progression and allow early treatment of life-threatening UC. Many patients may not complete the surveillance protocol, and the cost of these studies is increasing. In addition, questions about the efficacy of these modalities have been raised. Therefore, bladder urinary tumor markers have been developed to aid in the diagnosis and surveillance of UC. Because urothelial cells are bathed in the urine and are continually shed, UC presents a unique opportunity to monitor bladder neoplasia in a noninvasive fashion. Currently, there are many research bladder tumor markers, but only a few are commercially available US Food and Drug Administration (FDA)-approved products. The commercially available bladder tumor markers and potential future markers are discussed. The ideal urinary bladder tumor test is still unavailable, but the eventual "gold standard" will consist of multiplex assays that analyze nucleic acids and proteins for detection. In addition, these tests would also reveal to the clinician both prognostic information and therapeutic targets for personalized medical treatment.

Biomarkers, Tumor↗
PubMed2004

Effects of resveratrol on gene expression in renal cell carcinoma.

Studies have shown that Resveratrol (RE) can inhibit cancer initiation, promotion, and progression. However the gene expression profile in renal cell carcinoma (RCC) in response to RE treatment has never been reported. To understand the potential anticancer effect of RE on RCC at molecular level, we profiled and analyzed the expression of 2059 cancer-related genes in a RCC cell line RCC54 treated with RE. Biological functions of 633 genes were annotated based on biological process ontology and clustered into functional categories. Twenty-nine highly differentially expressed genes in RE treated RCC54 were identified and the potential implications of some gene expression alterations in RCC carcinogenesis were identified. RE was also shown to inhibit cell growth and induce cell death of RCC cells. The expression alterations of selected genes were validated using reverse transcription polymerase chain reaction. In addition, the gene expression profiles under different RE treatments were analyzed and visualized using singular value decomposition. The findings from this study support the hypothesis that RE induces differential expression of genes that are directly or indirectly related to the inhibition of RCC cell growth and induction of RCC cell death. In addition, it is apparent that the gene expression alterations due to RE treatment depend strongly on RE concentration. This study provides a general understanding of the overall genetic response of RCC54 to RE treatment and yields insights into the understanding of the cancer preventive mechanism of RE in RCC.

Angiogenesis Inhibitors↗
PubMed2004

Microarray gene expression profiling and analysis in renal cell carcinoma.

BACKGROUND: Renal cell carcinoma (RCC) is the most common cancer in adult kidney. The accuracy of current diagnosis and prognosis of the disease and the effectiveness of the treatment for the disease are limited by the poor understanding of the disease at the molecular level. To better understand the genetics and biology of RCC, we profiled the expression of 7,129 genes in both clear cell RCC tissue and cell lines using oligonucleotide arrays. METHODS: Total RNAs isolated from renal cell tumors, adjacent normal tissue and metastatic RCC cell lines were hybridized to affymatrix HuFL oligonucleotide arrays. Genes were categorized into different functional groups based on the description of the Gene Ontology Consortium and analyzed based on the gene expression levels. Gene expression profiles of the tissue and cell line samples were visualized and classified by singular value decomposition. Reverse transcription polymerase chain reaction was performed to confirm the expression alterations of selected genes in RCC. RESULTS: Selected genes were annotated based on biological processes and clustered into functional groups. The expression levels of genes in each group were also analyzed. Seventy-four commonly differentially expressed genes with more than five-fold changes in RCC tissues were identified. The expression alterations of selected genes from these seventy-four genes were further verified using reverse transcription polymerase chain reaction (RT-PCR). Detailed comparison of gene expression patterns in RCC tissue and RCC cell lines shows significant differences between the two types of samples, but many important expression patterns were preserved. CONCLUSIONS: This is one of the initial studies that examine the functional ontology of a large number of genes in RCC. Extensive annotation, clustering and analysis of a large number of genes based on the gene functional ontology revealed many interesting gene expression patterns in RCC. Most notably, genes involved in cell adhesion were dominantly up-regulated whereas genes involved in transport were dominantly down-regulated. This study reveals significant gene expression alterations in key biological pathways and provides potential insights into understanding the molecular mechanism of renal cell carcinogenesis.

Adenocarcinoma, Clear Cell↗
PubMed2004

Differential protein profiling in renal-cell carcinoma.

Characterizing the alterations of protein expression in cancer cells can be very useful in providing insight into the changes in the functional pathways and thus the fundamental mechanisms of cancer development at the molecular level. In this study, we profiled protein expressions in eleven pairs of primary cell cultures derived from renal-cell carcinoma (RCC) tissues and patient-matched normal kidney tissues utilizing two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Together with the immunoblot analysis of proteins from the RCC tissues, the study also demonstrated that the alterations of protein expression observed in RCC primary cell cultures reflected those observed in the original RCC tissues. We analyzed the expression profiles and identified proteins differentially expressed in RCC primary cell cultures by 2-D PAGE and mass spectrometry (MS). We found sixteen proteins were overexpressed and seven proteins underexpressed in RCC. The deregulated expressions of proteins include those involved in metabolism, cellular morphology, heat shock response, cell growth, etc. Overexpression of three proteins, alphabeta-crystallin, manganese superoxide dismutase (MnSOD), and annexin IV, most commonly observed in primary RCC cell cultures, were also observed by immunoblot analysis of proteins from the RCC tissues from which the primary cell cultures were derived. Semi-quantitative reverse transcription (RT)-polymerase chain reaction (PCR) analysis revealed the direct correlation between deregulated gene expression and the corresponding protein abundance in two of the three most commonly upregulated proteins we found in RCC.

Annexin A4↗
PubMed2003

Previously unidentified changes in renal cell carcinoma gene expression identified by parametric analysis of microarray data.

BACKGROUND: Renal cell carcinoma is a common malignancy that often presents as a metastatic-disease for which there are no effective treatments. To gain insights into the mechanism of renal cell carcinogenesis, a number of genome-wide expression profiling studies have been performed. Surprisingly, there is very poor agreement among these studies as to which genes are differentially regulated. To better understand this lack of agreement we profiled renal cell tumor gene expression using genome-wide microarrays (45,000 probe sets) and compare our analysis to previous microarray studies. METHODS: We hybridized total RNA isolated from renal cell tumors and adjacent normal tissue to Affymetrix U133A and U133B arrays. We removed samples with technical defects and removed probesets that failed to exhibit sequence-specific hybridization in any of the samples. We detected differential gene expression in the resulting dataset with parametric methods and identified keywords that are overrepresented in the differentially expressed genes with the Fisher-exact test. RESULTS: We identify 1,234 genes that are more than three-fold changed in renal tumors by t-test, 800 of which have not been previously reported to be altered in renal cell tumors. Of the only 37 genes that have been identified as being differentially expressed in three or more of five previous microarray studies of renal tumor gene expression, our analysis finds 33 of these genes (89%). A key to the sensitivity and power of our analysis is filtering out defective samples and genes that are not reliably detected. CONCLUSIONS: The widespread use of sample-wise voting schemes for detecting differential expression that do not control for false positives likely account for the poor overlap among previous studies. Among the many genes we identified using parametric methods that were not previously reported as being differentially expressed in renal cell tumors are several oncogenes and tumor suppressor genes that likely play important roles in renal cell carcinogenesis. This highlights the need for rigorous statistical approaches in microarray studies.

Aged↗
PubMed2003

Multitarget fluorescence in situ hybridization assay detects transitional cell carcinoma in the majority of patients with bladder cancer and atypical or negative urine cytology.

PURPOSE: The multitarget fluorescence in situ hybridization (FISH) probe set UroVysion (Vysis, Downers Grove, Illinois), containing probes to chromosomes 3, 7 and 17, and to the 9p21 band, has been recently shown to have high sensitivity and specificity for detecting transitional cell carcinoma. In this study we retrospectively tested 120 urine samples from patients with atypical, suspicious and negative cytology for whom concurrent and followup bladder biopsy data were available. We evaluated the ability of FISH to identify malignant cells in cytologically equivocal or negative cases. MATERIALS AND METHODS: Archived slides from 120 voided (47) or instrumented (73) urine cytology specimens from patients with concurrent bladder biopsy and a minimum of 12 months of biopsy followup were subjected to hybridization with UroVysion. The cohort included patients with biopsy proven transitional cell carcinoma, which was grades 1 to 3 in 23, 35 and 24, respectively, and stages pTis in 3, pTa in 64, pT1 in 6, pT2 in 6 and pT4 in 3, while it showed negative histology in 38. Cytology findings were suspicious, atypical and negative for transitional cell carcinoma in 31, 49 and 40 cases, respectively. A positive FISH result was defined as 5 transitional cells or greater with a gain of 2 or more of chromosomes 3, 7 or 17, 12 cells or greater with 9p21 deletion, or 10% or greater of cells with isolated trisomy of 1 of chromosomes 3, 7 and 17. RESULTS: All except 12 of the 82 biopsy proven transitional cell carcinoma cases (11 pTa and 1 pT1 tumors) were positive by FISH (85% sensitivity). Sensitivity in patients with suspicious, atypical and negative cytology was 100%, 89% and 60%, respectively. Nine patients with atypical cytology had positive FISH in the setting of a negative concurrent bladder biopsy. However, 8 of these 9 patients (89%) had biopsy proven transitional cell carcinoma within 12 months following the date when the sample tested by FISH was obtained. The last of these patients with false-positive results had previously documented pTis disease, which was also present in the next bladder biopsy 15 months following the positive FISH result. The remaining 29 specimens from patients with negative biopsy and a negative 12-month followup tested negative by FISH (97% overall specificity). CONCLUSIONS: The UroVysion FISH assay provides high sensitivity and specificity to detect transitional cell carcinoma in cytologically equivocal and negative urine samples. These results emphasize the important role of this assay in the management of bladder cancer.

Biopsy↗
PubMed2002

Interphase fluorescence in-situ hybridization in the diagnosis of bladder cancer.

Interphase FISH is a technique that uses fluorescent molecules to detect chromosomes or specific regions of DNA. It is a rapid and powerful technique for detection of cytogenetic abnormalities in malignant cells independent of their cell cycle status. Using variety of pericentromeric and locus-specific probes, numerical chromosomal changes (aneusomy) as well as loss or gain/amplification of specific genetic regions can be detected in clinical samples. Numerous studies have identified genetic alterations at the DNA level, occurring in the pathogenesis of variety of human neoplasms including bladder cancer, some of which can be used for detection, prognosis, and as intermediate endpoints for evaluating the response to therapy. Recently, sensitivity and specificity of a multicolor FISH assay consisting of four probes (3, 7, 17 and 9p21) was analyzed in several prospective and retrospective studies. The data suggest that this method applicable to voided urine specimens may allow safe extension of the interval between cystoscopies in routine surveillance of patients with transitional cell carcinoma of the bladder. FISH analysis of cells isolated from bladder washings or voided urine is also holding promise for monitoring of treatment outcome and predicting recurrence and progression of the disease. Therefore, this technique can be an important aid in the efforts to reduce mortality from transitional cell carcinoma of the bladder, since it increases our ability to prevent progression to incurable muscle invasive disease.

In Situ Hybridization, Fluorescence↗
PubMed2002

Prognostic importance of resection margin width after nephron-sparing surgery for renal cell carcinoma.

OBJECTIVES: To examine the relationship between the width of the resection margin and disease progression in renal cell carcinoma (RCC) after nephron-sparing surgery (NSS). During NSS for RCC, it is standard practice to excise the tumor along with a surrounding margin of normal parenchyma (margin of resection) to ensure complete resection of the neoplasm. However, no agreement has been reached on how wide the margin of resection should be. METHODS: We retrospectively reviewed the histopathologic sections and medical records of 69 patients with localized RCC who had undergone NSS between 1976 and 1988 to determine whether the resection margin, tumor size, TNM stage, and Fuhrman nuclear grade were associated with disease progression (defined as local tumor recurrence or metastasis). The mean postoperative follow-up interval was 8.5 years. RESULTS: No association was found between the width of the resection margin and disease progression (P = 0.98, log-rank test). Both TNM stage and Fuhrman nuclear grade correlated with disease progression. Patients with T1-T2 tumors had lower progression (P <0.001, log-rank test), and increased Fuhrman nuclear grade correlated with more disease progression (P <0.001, log-rank test). CONCLUSIONS: The width of the resection margin after NSS for RCC does not correlate with long-term disease progression. A histologic tumor-free margin of resection, irrespective of the width of the margin is sufficient to achieve complete local excision of RCC.

Adult↗