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Biomedical subjects

Keyue Ding

Publications and source records attributed to Keyue Ding.

13 recordsLinked to original sources
PubMed2005

Erlotinib in lung cancer - molecular and clinical predictors of outcome.

BACKGROUND: A clinical trial that compared erlotinib with a placebo for non-small-cell lung cancer demonstrated a survival benefit for erlotinib. We used tumor-biopsy samples from participants in this trial to investigate whether responsiveness to erlotinib and its impact on survival were associated with expression by the tumor of epidermal growth factor receptor (EGFR) and EGFR gene amplification and mutations. METHODS: EGFR expression was evaluated immunohistochemically in non-small-cell lung cancer specimens from 325 of 731 patients in the trial; 197 samples were analyzed for EGFR mutations; and 221 samples were analyzed for the number of EGFR genes. RESULTS: In univariate analyses, survival was longer in the erlotinib group than in the placebo group when EGFR was expressed (hazard ratio for death, 0.68; P=0.02) or there was a high number of copies of EGFR (hazard ratio, 0.44; P=0.008). In multivariate analyses, adenocarcinoma (P=0.01), never having smoked (P<0.001), and expression of EGFR (P=0.03) were associated with an objective response. In multivariate analysis, survival after treatment with erlotinib was not influenced by the status of EGFR expression, the number of EGFR copies, or EGFR mutation. CONCLUSIONS: Among patients with non-small-cell lung cancer who receive erlotinib, the presence of an EGFR mutation may increase responsiveness to the agent, but it is not indicative of a survival benefit.

Adenocarcinoma↗
PubMed2005

Vinorelbine plus cisplatin vs. observation in resected non-small-cell lung cancer.

BACKGROUND: We undertook to determine whether adjuvant vinorelbine plus cisplatin prolongs overall survival among patients with completely resected early-stage non-small-cell lung cancer. METHODS: We randomly assigned patients with completely resected stage IB or stage II non-small-cell lung cancer to vinorelbine plus cisplatin or to observation. The primary end point was overall survival; principal secondary end points were recurrence-free survival and the toxicity and safety of the regimen. RESULTS: A total of 482 patients underwent randomization to vinorelbine plus cisplatin (242 patients) or observation (240); 45 percent of the patients had pathological stage IB disease and 55 percent had stage II, and all had an Eastern Cooperative Oncology Group performance status score of 0 or 1. In both groups, the median age was 61 years, 65 percent were men, and 53 percent had adenocarcinomas. Chemotherapy caused neutropenia in 88 percent of patients (including grade 3 febrile neutropenia in 7 percent) and death from toxic effects in two patients (0.8 percent). Nonhematologic toxic effects of chemotherapy were fatigue (81 percent of patients), nausea (80 percent), anorexia (55 percent), vomiting (48 percent), neuropathy (48 percent), and constipation (47 percent), but severe (grade 3 or greater) toxic effects were uncommon (<10 percent). Overall survival was significantly prolonged in the chemotherapy group as compared with the observation group (94 vs. 73 months; hazard ratio for death, 0.69; P=0.04), as was relapse-free survival (not reached vs. 46.7 months; hazard ratio for recurrence, 0.60; P<0.001). Five-year survival rates were 69 percent and 54 percent, respectively (P=0.03). CONCLUSIONS: Adjuvant vinorelbine plus cisplatin has an acceptable level of toxicity and prolongs disease-free and overall survival among patients with completely resected early-stage non-small-cell lung cancer.

Adult↗
PubMed2005

Randomized comparison of ABVD chemotherapy with a strategy that includes radiation therapy in patients with limited-stage Hodgkin's lymphoma: National Cancer Institute of Canada Clinical Trials Group and the Eastern Cooperative Oncology Group.

PURPOSE: We report results of a randomized trial comparing ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine) chemotherapy alone with treatment that includes radiation therapy in patients with limited-stage Hodgkin's lymphoma. PATIENTS AND METHODS: Patients with nonbulky clinical stage I to IIA Hodgkin's lymphoma were stratified into favorable and unfavorable risk cohorts. Patients allocated to radiation-containing therapy received subtotal nodal radiation if favorable risk or combined-modality therapy if unfavorable risk. Patients allocated to ABVD received four to six treatment cycles. RESULTS: We evaluated 399 patients. Median follow-up is 4.2 years. In comparison with ABVD alone, 5-year freedom from disease progression is superior in patients allocated to radiation therapy (P = .006; 93% v 87%); no differences in event-free survival (P = .06; 88% v 86%) or overall survival (P = .4; 94% v 96%) were detected. In a subset analyses comparing patients stratified into the unfavorable cohort, freedom from disease progression was superior in patients allocated to combined-modality treatment (P = .004; 95% v 88%); no difference in overall survival was detected (P = .3; 92% v 95%). Of 15 deaths observed, nine were attributed to causes other than Hodgkin's lymphoma or acute treatment-related toxicity. CONCLUSION: In patients with limited-stage Hodgkin's lymphoma, no difference in overall survival was detected between patients randomly assigned to receive treatment that includes radiation therapy or ABVD alone. Although 5-year freedom from disease progression was superior in patients receiving radiation therapy, this advantage is offset by deaths due to causes other than progressive Hodgkin's lymphoma or acute treatment-related toxicity.

Adult↗
PubMed2005

htSNPer1.0: software for haplotype block partition and htSNPs selection.

BACKGROUND: There is recently great interest in haplotype block structure and haplotype tagging SNPs (htSNPs) in the human genome for its implication on htSNPs-based association mapping strategy for complex disease. Different definitions have been used to characterize the haplotype block structure in the human genome, and several different performance criteria and algorithms have been suggested on htSNPs selection. RESULTS: A heuristic algorithm, generalized branch-and-bound algorithm, is applied to the searching of minimal set of haplotype tagging SNPs (htSNPs) according to different htSNPs performance criteria. We develop a software htSNPer1.0 to implement the algorithm, and integrate three htSNPs performance criteria and four haplotype block definitions for haplotype block partitioning. It is a software with powerful Graphical User Interface (GUI), which can be used to characterize the haplotype block structure and select htSNPs in the candidate gene or interested genomic regions. It can find the global optimization with only a fraction of the computing time consumed by exhaustive searching algorithm. CONCLUSION: htSNPer1.0 allows molecular geneticists to perform haplotype block analysis and htSNPs selection using different definitions and performance criteria. The software is a powerful tool for those focusing on association mapping based on strategy of haplotype block and htSNPs.

Algorithms↗
PubMed2005

Compliance with post-operative adjuvant chemotherapy in non-small cell lung cancer. An analysis of National Cancer Institute of Canada and intergroup trial JBR.10 and a review of the literature.

Resected non-small cell lung cancer (NSCLC) has 5-years survival rates of 30-70%. The role of adjuvant chemotherapy remains unclear with poor compliance reported in most trials. The compliance with adjuvant chemotherapy (ACT) for stage IB and II NSCLC was analyzed using data from a North American multi-centre phase III study (accrual 1994-2001) that compared adjuvant chemotherapy to observation. Planned chemotherapy consisted of cisplatin (CIS) 50 mg/m2 days 1, 8 and vinorelbine (VIN) 25 mg/m2 days 1, 8, 15, 22 for four cycles; the VIN dose had been reduced from 30 mg/m2 after an initial cohort of patients experienced unacceptable toxicity. Four hundred and twenty-four patients were randomized after the amendment, 215 to the chemotherapy arm. Median age was 60 years, 64% were male and 84% had stage II disease. Thirty-seven patients completed one cycle, 14 completed two, 20 completed three and 108 patients completed all four cycles. Ten patients received no therapy. Multivariate analysis demonstrated statistically significant differences in compliance with extent of surgery, gender and age. Patients randomized in Canada were more likely to fail to complete chemotherapy due to refusal of therapy than their American counterparts. Patients who had pneumonectomies were more likely to discontinue therapy due to toxicity than those who had lesser resections. Extent of surgery may play a role in both the compliance and toxicity of ACT. Differences between nations in the perception of the risks and benefits of adjuvant chemotherapy regimens, both between physicians and patients, should be investigated further.

Adult↗
PubMed2004

Results of a multicenter randomized phase II trial of thalidomide and prednisone maintenance therapy for multiple myeloma after autologous stem cell transplant.

We report a multicenter, randomized phase II trial conducted to assess the tolerability of combined thalidomide and prednisone maintenance in multiple myeloma. Eligibility required administration of melphalan (200 mg/m2) with blood stem cell support within 1 year of treatment onset and initiation of maintenance within 60 to 100 days after stem cell infusion. All patients received 50 mg of prednisone by mouth on alternate days and thalidomide at a starting dose of either 200 or 400 mg daily by mouth. The primary end point was the incidence of dropout or dose reduction due to treatment toxicity within 6 months. Sixty-seven patients were enrolled. Median follow-up is 36.8 months. The primary end point was reached by 31% of patients on the 200 mg of thalidomide arm and 64% of patients on the 400 mg of thalidomide arm. Allowing for dose reduction, 76% of patients assigned to the 200 mg of thalidomide arm and 41% of patients assigned to the 400 mg of thalidomide arm remained on any maintenance therapy 18 months after registration. Eighty-eight percent of all patients dose-reduced thalidomide and 72% of all patients dose-reduced prednisone within 2 years of beginning maintenance. The median progression-free survival post-transplant is 32.3 months, or 42.2 months from diagnosis. Only the 200 mg of thalidomide arm of this trial met our definition of a tolerable maintenance therapy, defined as no dose reductions or discontinuation due to toxicity in at least 65% of patients for a minimum of 6 months, thus establishing a dosing schedule for phase III trials.

Aged↗
PubMed2004

Gemcitabine, dexamethasone, and cisplatin in patients with recurrent or refractory aggressive histology B-cell non-Hodgkin lymphoma: a Phase II study by the National Cancer Institute of Canada Clinical Trials Group (NCIC-CTG).

BACKGROUND: Gemcitabine has been shown to have activity as a single agent in lymphoma and, when combined with cisplatin, is effective therapy for a number of solid tumors. The authors wished to determine the response rate and toxicity of gemcitabine, dexamethasone, and cisplatin for recurrent or refractory non-Hodgkin lymphoma (NHL). METHODS: Patients with recurrent or refractory diffuse large B-cell NHL or variants (REAL classification), measurable disease, and one previous chemotherapy regimen were eligible. Treatment consisted of gemcitabine 1000 mg/m(2) intravenously (i.v.) on Days 1 and 8, dexamethasone 40 mg orally on Days 1-4, and cisplatin 75 mg/m(2) i.v. on Day 1 (GDP), every 21 days as an outpatient. The primary end point was a response after two cycles. Patients could then proceed to stem cell transplantation (SCT) or receive up to six treatment cycles. RESULTS: Fifty-one eligible patients were evaluable for toxicity and response. The median age of the patients was 57 years (range, 18-84 years) and most had diffuse large-cell lymphoma. After 2 cycles, there were 8 complete responses (CR; 16%) and 17 partial responses (PR; 33%). There was an overall response rate (RR) of 49% (95% confidence interval = 37-63%). The RR afer completion of all protocol chemotherapy (including those who received > 2 cycles of GDP) was 53% (11 CR, 16 PR). Grade 3 and 4 neutropenia occurred in 33% and 39% of patients, respectively. Grade 3 and 4 thrombocytopenia occurred in 24% and 4% of patients, respectively. Seven patients (14%) experienced febrile neutropenia. Of the 35 patients < 66 years, 22 (63%) proceeded to SCT. CONCLUSIONS: GDP is an active regimen in B-cell NHL and can be administered with acceptable toxicity to outpatients. A Phase III trial comparing GDP with standard cisplatin-based chemotherapy is now ongoing through the National Cancer Institute of Canada Clinical Trials Group.

Administration, Oral↗
PubMed2004

The effect of haplotype-block definitions on inference of haplotype-block structure and htSNPs selection.

It has been recently suggested that the human genome is organized as a series of haplotype blocks, and efforts to create a genome-wide haplotype map are already underway. Several computational algorithms have been proposed to partition the genome. However, little is known about their behaviors in relation to the haplotype-block partitioning and haplotype-tagging SNPs selection. Here, we present a systematic comparison of three classes of haplotype-block partition definitions, a diversity-based method, a linkage-disequilibrium (LD)-based method, and a recombination-based method. The data used were derived from a coalescent simulation under both a uniform recombination model and one that assumes recombination hotspots. There were considerable differences in haplotype information loss in the measure of entropy when the partition methods were compared under different population-genetics scenarios. Under both recombination models, the results from the LD-based definition and the recombination-based definition were more similar to each other than were the results from the diversity-based definition. This work demonstrates that when undertaking haplotype-based association mapping, the choice of haplotype-block definition and SNP selection requires careful consideration.

Algorithms↗
PubMed2003

LDA--a java-based linkage disequilibrium analyzer.

UNLABELLED: We describe an integrated java-based program that provides elaborate graphic and plain-text output of pairwise linkage disequilibrium (LD) analysis of single nucleotide polymorphisms genotypic data. It is most suitable for molecular geneticists, who are focusing on LD measures estimation, statistical significance test and extent prediction. AVAILABILITY: The software is available at: http://www.chgb.org.cn/lda/lda.htm. SUPPLEMENTARY INFORMATION: Detailed tutorials, LDA help system and examples are distributed within LDA software. For Macintosh OS X user, the Jre version 1.4 can be downloaded from http://connect.apple.com.

Algorithms↗
PubMed2003

Association between genetic variation of CACNA1H and childhood absence epilepsy.

Direct sequencing of exons 3 to 35 and the exon-intron boundaries of the CACNA1H gene was conducted in 118 childhood absence epilepsy patients of Han ethnicity recruited from North China. Sixty-eight variations have been detected in the CACNA1H gene, and, among the variations identified, 12 were missense mutations and only found in 14 of the 118 patients in a heterozygous state, but not in any of 230 unrelated controls. The identified missense mutations occurred in the highly conserved residues of the T-type calcium channel gene. Our results suggest that CACNA1H might be an important susceptibility gene involved in the pathogenesis of childhood absence epilepsy.

Age of Onset↗
PubMed2002

Mutation screen of the GABA(A) receptor gamma 2 subunit gene in Chinese patients with childhood absence epilepsy.

Childhood absence epilepsy (CAE) is considered to be a genetic disease, the genes responsible for which have not yet been identified. To investigate whether or not GABA(A) receptor gamma 2 subunit gene (GABRG2) is the susceptibility gene for CAE in the Chinese population, we screened 68 CAE patients of Han ethnicity from North China for mutations in the nine exons of GABRG2. Although we found no mutation in the exons of GABRG2, we did identify two single nucleotide polymorphisms (SNPs) in exon 3 and exon 5. Using the two SNPs as markers, we carried out a transmission/disequilibrium test (TDT) in 68 trios with CAE. TDT results showed that there were no significant discrepancies between the CAE patients and 'internal controls' in allele frequencies of the two SNPs. We postulate that the GABRG2 gene might be neither a susceptibility gene for CAE nor in linkage disequilibrium with disease-predisposing sites in the Chinese population.

Adolescent↗
PubMed2002

Genome sequence of Shigella flexneri 2a: insights into pathogenicity through comparison with genomes of Escherichia coli K12 and O157.

We have sequenced the genome of Shigella flexneri serotype 2a, the most prevalent species and serotype that causes bacillary dysentery or shigellosis in man. The whole genome is composed of a 4 607 203 bp chromosome and a 221 618 bp virulence plasmid, designated pCP301. While the plasmid shows minor divergence from that sequenced in serotype 5a, striking characteristics of the chromosome have been revealed. The S.flexneri chromosome has, astonishingly, 314 IS elements, more than 7-fold over those possessed by its close relatives, the non-pathogenic K12 strain and enterohemorrhagic O157:H7 strain of Escherichia coli. There are 13 translocations and inversions compared with the E.coli sequences, all involve a segment larger than 5 kb, and most are associated with deletions or acquired DNA sequences, of which several are likely to be bacteriophage-transmitted pathogenicity islands. Furthermore, S.flexneri, resembling another human-restricted enteric pathogen, Salmonella typhi, also has hundreds of pseudogenes compared with the E.coli strains. All of these could be subjected to investigations towards novel preventative and treatment strategies against shigellosis.

Amino Acid Sequence↗