Biomedical subjects

I-Shou Chang

Publications and source records attributed to I-Shou Chang.

9 recordsLinked to original sources

PubMed2025

Stratifying Lung Adenocarcinoma Risk with Multi-ancestry Polygenic Risk Scores in East Asian Never-Smokers.

BACKGROUND: Lung adenocarcinoma (LUAD) in never-smokers is a major public health burden, especially among East Asian women. Polygenic risk scores (PRSs) are promising for risk stratification but are primarily developed in European-ancestry populations. We aimed to develop and validate single- and multi-ancestry PRSs for East Asian never-smokers to improve LUAD risk prediction. METHODS: PRSs were developed using genome-wide association study summary statistics from East Asian (8,002 cases; 20,782 controls) and European (2,058 cases; 5,575 controls) populations. Single-ancestry models included PRS-25, PRS-CT, and LDpred2; multi-ancestry models included LDpred2+PRS-EUR128, PRS-CSx, and CT-SLEB. Performance was evaluated in independent East Asian data from the Female Lung Cancer Consortium (FLCCA) and externally validated in the Nanjing Lung Cancer Cohort (NJLCC). We assessed predictive accuracy via AUC, with 10-year and (age 30-80) absolute risks estimates. RESULTS: The best multi-ancestry PRS, using East Asian and European data via CT-SLEB (clumping and thresholding, super learning, empirical Bayes), outperformed the best East Asian-only PRS (LDpred2; AUC=0.629, 95% CI:0.618,0.641), achieving an AUC of 0.640 (95% CI:0.629,0.653) and odds ratio of 1.71 (95% CI:1.61,1.82) per SD increase. NJLCC Validation confirmed robust performance (AUC =0.649, 95% CI: 0.623, 0.676). The top 20% PRS group had a 3.92-fold higher LUAD risk than the bottom 20%. Further, the top 5% PRS group reached a 6.69% lifetime absolute risk. Notably, this group reached the average population 10-year LUAD risk at age 50 (0.42%) by age 41, nine years earlier. CONCLUSIONS: Multi-ancestry PRS approaches enhance LUAD risk stratification in East Asian never-smokers, with consistent external validation, suggesting future clinical utility.

East Asian never smokers↗

PubMed2025

A prognostic signature for lung adenocarcinoma in people who have never smoked.

Knowledge of tumor cell dynamics can inform prognosis and treatment yet is largely lacking for lung adenocarcinoma in people who have never smoked (NS-LUAD). With RNA-seq data from 684 NS-LUAD and validation in an independent dataset, we identified three subtypes with distinct phenotypic traits and cell compositions. Additional genomic and histological data further characterized the subtypes. 'Steady', marked by low proliferation, high alveolar cell fraction, moderate-to-well differentiation, and fewer driver genes' alterations, is linked to prolonged survival and low immune evasion. 'Proliferative' shows high proliferation markers, TP53 mutations, and gene fusions. 'Chaotic', with high epithelial-to-mesenchymal transition markers, has the worst prognosis even within stage I tumors. Lacking known molecular or histological characteristics, this aggressive subtype is solely identified by transcriptomic data. A 60-gene signature recapitulates the overall classification and strongly predicts survival even within subgroups based on tumor stage or known genomic features, emphasizing its potential for improving NS-LUAD prognostication in clinical settings.

Journal Article↗

PubMed2007

Usage of the claim database of national health insurance programme for analysis of cisapride-erythromycin co-medication in Taiwan.

PURPOSE: This study aimed to use the National Health Insurance Research Database, Taiwan for risk analysis of concomitant use of cisapride and erythromycin. METHODS: The sample consisted of subjects identified in the Outpatient Sampling Database (OSD) and Longitudinal Health Insurance Database 2000 (LHID 2000), derived from the original claim data of the National Health Insurance Research Database, Taiwan. RESULTS: According to the LHID 2000, a total of 464 individuals experienced 685 episodes of cisapride-erythromycin co-medication prescribed by 295 physicians, revealing a prevalence of 4.5% concomitant use, with higher prevalence in clinics (9.2%) than in other medical institutes (3.7-5.4%). Among the co-medication episodes, 81.9% and 61.2% were prescribed from the same health institutes and by the same physicians, respectively. No medical record of cardiac arrhythmias was found among these patients in 2001 and 2002, probably due to the fact that 78.9% of the 464 individuals were under age 16, 84.0% had short exposure duration (1-4 days) and 98.0% of the episodes were prescribed with a cisapride dose of less than 0.8 mg/kg/day. CONCLUSIONS: Findings from this study suggest that there exists an urgent need for accreditation in terms of pharmacovigilance of clinical sites and their practicing physicians for the prevention of irrational concomitant prescription in Taiwan. Our findings also indicate that it is necessary to investigate other possible conditions of potentially dangerous co-medication in Taiwan and other developing countries.

Adolescent↗

PubMed2006

A Bayes regression approach to array-CGH data.

This paper develops a Bayes regression model having change points for the analysis of array-CGH data by utilizing not only the underlying spatial structure of the genomic alterations but also the observation that the noise associated with the ratio of the fluorescence intensities is bigger when the intensities get smaller. We show that this Bayes regression approach is particularly suitable for the analysis of cDNA microarray-CGH data, which are generally noisier than those using genomic clones. A simulation study and a real data analysis are included to illustrate this approach.

Bayes Theorem↗

PubMed2006

Incorporating endophenotypes into allele-sharing based linkage tests.

For a genetic study in which there are concordant and discordant sibpairs for a complex disease trait and the measurements of other endophenotypes/intermediate phenotypes for each of the individuals are also available, we describe an allele-sharing based multipoint linkage test that utilizes nonparametrically the additional endophenotypes/intermediate phenotypes. The usefulness of this method is evaluated in simulation studies, which show that the gain in power is influenced by not only the endophenotypic value but also the correlation between the diagnosis-based phenotype and the endophenotype. In addition to reporting p values, our method also provides an index C(E), derived from the coefficients of the weight function associated with the endophenotype in the proposed statistic, to indicate the relevance of a specific endophenotype/intermediate phenotype in the genetic study. The simulation study indicates that a larger power, in general, corresponds to a larger value of the index C(E). The index C(E) is thus suggested as a quantity to be used in the choice of endophenotypes in linkage study. Data from the Stanford Asian Pacific Program in Hypertension and Insulin Resistance (SAPPHIRe) are used to illustrate the method.

Adult↗

PubMed2006

Complications following D3 gastrectomy: post hoc analysis of a randomized trial.

INTRODUCTION: A single institutional surgical trial for gastric cancer had demonstrated increased morbidity but not mortality. This report analyzes risk factors affecting morbidity. METHODS: Risk factors for morbidity in 221 patients treated with curative intent were evaluated in a prospective randomized trial comparing D1 and D3 surgery for curable gastric cancer. RESULTS: The surgeon's experience after 25 nodal dissections had no influence on surgical or overall complications, nor did the patients' co-morbidity (e.g., respiratory system disease, cardiac disease, diabetes mellitus). Distal pancreatectomy negatively affected surgical morbidity [relative risk (RR) 6.21, 95% confidence interval (CI) 1.869-20.626] and overall morbidity (RR 5.50, 95% CI 1.671-18.082). All of the patients with a distal pancreatectomy underwent concomitant splenectomy. Multivariate analysis found splenectomy and nodal dissection to be the only two independent risk factors adversely affecting operative morbidity. The RR of splenectomy for surgical complications was 4.19 (95% CI 1.327-13.208), and for overall complications it was 3.88 (95% CI 1.259-11.973). The RR of nodal dissection for surgical complications was 2.51 (95% CI 1.336-4.730), and for overall complications it was 1.93 (95% CI 1.149-3.255). CONCLUSIONS: Splenectomy (with or without pancreatectomy) and nodal dissection are risk factors for operative morbidity but not mortality.

Aged↗

PubMed2006

Temporal transcription program of recombinant Autographa californica multiple nucleopolyhedrosis virus.

Baculoviruses, a family of large, rod-shaped viruses that mainly infect lepidopteran insects, have been widely used to transduce various cells for exogenous gene expression. Nonetheless, how a virus controls its transcription program in cells is poorly understood. With a custom-made baculovirus DNA microarray, we investigated the recombinant Autographa californica multiple nucleopolyhedrosis virus (AcMNPV) gene expression program in lepidopteran Sf21 cells over the time course of infection. Our analysis of transcription kinetics in the cells uncovered sequential viral gene expression patterns possibly regulated by different mechanisms during different phases of infection. To gain further insight into the regulatory network, we investigated the transcription program of a mutant virus deficient in an early transactivator (pe38) and uncovered several pe38-dependent and pe38-independent genes. This study of baculovirus dynamic transcription programs in different virus genetic backgrounds provides new molecular insights into how gene expression in viruses is regulated.

Animals↗

PubMed2005

Revealing molecular targets for enterovirus type 71 detection by profile hidden Markov models.

The enterovirus infection in 1998 claimed 78 deaths in Taiwan, with an average of 40 fatalities each year after. Traditional serum-based diagnostic methods often fail to detect enteroviruses due to antigenic changes. As a result, many isolates remain untyped and are absent from the enterovirus surveillance and epidemiological investigations. We present a profile hidden Markov model (HMM) method for molecular typing of enterovirus 71 (EV71). Based on the enteroviral sequences retrieved from GenBank, we build a nucleotide-based and an amino acid-based profile HMM for each EV71 gene using the package HMMER. HMMER bit score-based Z-scores for EV71 and non-EV71 sequences are calculated for each of these profile HMMs. In a genome-wide analysis, we find that the distribution of the EV71 Z-scores and that of the non-EV71 Z-scores have disjoint support for nucleotide-based VP1 profile HMM if the sequence is longer than 150 bases; a VP1-based molecular typing method for EV71 is thus proposed. We also report VP4 an alternative molecular target for detecting EV71, while the two UTRs and all the genes coding the internal proteins cannot be used for such purpose. To demonstrate the performance of the nucleotide-based EV71 VP1 profile HMM, 330 enterovirus VP1 nucleotide sequences newly reported to GenBank are typed with this method. All the EV71 sequences are detected with no error.

Amino Acid Sequence↗

PubMed2004

Epidemiologic features of Kawasaki disease in Taiwan, 1996-2002.

OBJECTIVE: Kawasaki disease (KD) is the most common acquired heart disease in children worldwide. The incidence of KD varies among different countries, with Asian countries supposedly having higher incidences than Western countries. However, the incidence of KD in Taiwan has not been well investigated. METHODS: Since the implementation of Taiwan's National Health Insurance (NHI) in 1995, NHI has covered health care for >96% its population. Using the NHI database from 1996 to 2002, we investigated epidemiologic features of KD (International Classification of Diseases, Ninth Revision, code 446.1), the rate of coronary artery aneurysm formation (International Classification of Diseases, Ninth Revision, code 414.11), and the change in incidence during the recent 7 years. We also compared the annual incidences in Taiwan with those reported by other countries. RESULTS: During the 7-year study period, KD occurred most frequently in the summer and least frequently in winter. It is interesting that the highest peak occurred in the summer of 1998 at the same time that Taiwan's enterovirus 71 epidemic was occurring. Ninety-one percent of KD cases occurred in children who were <5 years old, and the male-to-female ratio was 1.70:1. Recurrence of KD was found in 1.3% (94 of 7305) of these children, and coronary artery aneurysm was found in 7.3% (536 of 7305). The annual incidence per 100,000 children was 146 in children <1 year old, 98 in 1-year-old children, 51 in 2-year-old children, 28 in 3-year-old children, 19 in 4-year-old children, and 5.3 in 5- to 9-year-old children; the incidence of KD decreased with increased age. The overall incidence was 66 cases per 100,000 children <5 years old from 1996 to 2002 with the annual incidence not differing significantly during the 7-year study period. CONCLUSIONS: KD in Taiwan occurs more frequently in boys and in the summer months. During the 7-year study period, the annual KD incidence in Taiwan of 66/100000 in children <5 years old was the second highest in the world after Japan.

Adolescent↗