Jeeyun Lee

Samsung Medical Center, Sŏul, Seoul, South Korea

Are you Jeeyun Lee?

Claim your profile

Publications (218)901.83 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The present study was aimed at discovering DNA copy number alterations (CNAs) involved in the carcinogenesis of stomach and at understanding their clinicopathological significances in the Korean population. DNA copy numbers were analyzed using Agilent 244K or 400K array comparative genomic hybridization (aCGH) in fresh-frozen tumor and matched normal tissues from 40 gastric cancer patients. Some of the detected CNA regions were validated using multiplex ligation-dependent probe amplification (MLPA) in six of the 40 patients and customized Agilent 60K aCGH in an independent set of 48 gastric cancers. The mRNA levels of genes at common CNA regions were analyzed using quantitative real-time PCR. Copy number gains were more common than losses across the entire genome in tumor tissues compared to matched normal tissues. The mean number of alterations per case was 64 for gains and 40 for losses, and the median aberration length was 44016 bp for gains and 4732 bp for losses. Copy number gains were frequently detected at 7p22.1 (20%), 8q24.21 (27%-30%), 8q24.3 (22%-48%), 13q34 (20%-31%), and 20q11-q13 (25%-30%), and losses at 3p14.2 (43%), 4q35.2 (27%), 6q26 (23%), and 17p13.3 (20%-23%). CNAs at 7p22.1, 13q34, and 17p13.3 have not been reported in other populations. Most of the copy number losses were associated with down-regulation of mRNA levels, but the correlation between copy number gains and mRNA expression levels varied in a gene-dependent manner. In addition, copy number gains tended to occur more commonly in intestinal-type cancers than in diffuse-type cancers. In conclusion, the present study suggests that copy number gains at 8q24 and 20q11-q13 and losses at 3p14.2 may be common events in gastric cancer but CNAs at 7p22.1, 13q34, and 17p13.3 may be Korean-specific.
    Preview · Article · Sep 2015 · PLoS ONE
  • [Show abstract] [Hide abstract]
    ABSTRACT: The efficacy of erlotinib, the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, has been demonstrated in patients with non-small cell lung cancer (NSCLC) and pancreatic cancer (PC). In the present study, we evaluated the effect of epidermal growth factor (EGF) ointment on erlotinib-related skin effects (ERSEs). This was an open-label, non-comparative, multicenter, phase II trial. The patients included those diagnosed with NSCLC or PC who were treated with erlotinib. The effectiveness of the ointment was defined as follows: (1) grade 2, 3, or 4 ERSEs downgraded to ≤grade 1 or (2) grade 3 or 4 ERSEs downgraded to grade 2 and persisted for at least 2 weeks. Fifty-two patients from seven institutes in Korea were enrolled with informed consent. The final assessment included 46 patients (30 males, 16 females). According to the definition of effectiveness, the EGF ointment was effective in 36 (69.2 %) intention to treat patients. There were no statistically significant differences in the effectiveness of the EGF ointment by gender (p = 0.465), age (p = 0.547), tumor type (p = 0.085), erlotinib dosage (p = 0.117), and number of prior chemotherapy sessions (p = 0.547). The grading for the average National Cancer Institute's Common Terminology Criteria for Adverse Events (NCI-CTCAE) rating of rash/acne and itching improved from 2.02 ± 0.83 to 1.13 ± 0.89 and 1.52 ± 0.84 to 0.67 ± 0.90, respectively (p < 0.001). The most common reason for discontinuing the study was progression of cancer (37 %). Based on the results, the EGF ointment is effective for ERSEs, regardless of gender, age, type of tumor, and dosage of erlotinib. The EGF ointment evenly improved all kinds of symptoms of ERSEs. ClinicalTrials.gov identifier: NCT01593995.
    No preview · Article · Jun 2015 · Supportive Care in Cancer
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study was aimed at understanding the functional and clinicopathological significance of MAPK15 alteration in gastric cancer. Genome-wide copy number alterations (CNAs) were first investigated in 40 gastric cancers using Agilent aCGH-244K or aCGH-400K, and copy number gains of MAPK15 found in aCGH were validated in another set of 48 gastric cancer tissues. The expression of MAPK15 was analyzed using immunohistochemistry in concurrent lesions of normal, adenoma, and carcinoma from additional 45 gastric cancer patients. The effects of MAPK15 on cell cycle, c-Jun phosphorylation, and mRNA stability were analyzed in gastric cancer cells. Copy number gains of MAPK15 were found in 15 (17%) of 88 tumor tissues. The mRNA levels of MAPK15 were relatively high in the gastric cancer tissues and gastric cancer cells with higher copy number gains than those without. Knockdown of MAPK15 using siRNA in gastric cancer cells significantly suppressed cell proliferation and resulted in cell cycle arrest at G1-S phase. Reduced c-Jun phosphorylation and c-Jun half-life were observed in MAPK15-knockdowned cells. In addition, transient transfection of MAPK15 into AGS gastric cancer cells with low copy number resulted in an increase of c-Jun phosphorylation and stability. The overexpression of MAPK15 occurred at a high frequency in carcinomas (37%) compared to concurrent normal tissues (2%) and adenomas (21%). In conclusion, the present study suggests that MAPK15 overexpression may contribute to the malignant transformation of gastric mucosa by prolonging the stability of c-Jun. And, patients with copy number gain of MAPK15 in normal or premalignant tissues of stomach may have a chance to progress to invasive cancer.
    Preview · Article · May 2015 · Oncotarget
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The role of MerTK has not been assessed in gastric cancer (GC). The aim of this study was to identify a subgroup of GC patients with MerTK tumor overexpression, and to evaluate MerTK as a potential therapeutic target in this disease. Protein and mRNA expression of MerTK were evaluated, and other various in vitro analyses including shRNA transfection, cell cycle anslysis, MTS assay and colony forming assay were carried out with GC cell lines and GC patient-derived cells (PDCs). shRNA-mediated knockdown of MerTK resulted in inhibition of cell growth, as well as increased cellular apoptosis in MerTK positive GC cells. Out of 192 GC patients, 16 (8.3%) patients showed strong protein expression and they had a significantly shorter overall survival compared to those with no MerTK expression. In 54 cases of GC PDCs, 4 cases (7.4%) showed mRNA overexpression, which was comparable to the protein expression rate. When we administered UNC1062, a novel MerTK-selective small molecular tyrosine kinase inhibitor, proliferation of MerTK overexpressing GC cells and PDCs were considerably inhibited. MerTK may be involved in GC carcinogenesis, and it could be a potential novel therapeutic target in GC patients.
    Preview · Article · Apr 2015 · Oncotarget
  • [Show abstract] [Hide abstract]
    ABSTRACT: Gastric cancer, a leading cause of cancer-related deaths, is a heterogeneous disease. We aim to establish clinically relevant molecular subtypes that would encompass this heterogeneity and provide useful clinical information. We use gene expression data to describe four molecular subtypes linked to distinct patterns of molecular alterations, disease progression and prognosis. The mesenchymal-like type includes diffuse-subtype tumors with the worst prognosis, the tendency to occur at an earlier age and the highest recurrence frequency (63%) of the four subtypes. Microsatellite-unstable tumors are hyper-mutated intestinal-subtype tumors occurring in the antrum; these have the best overall prognosis and the lowest frequency of recurrence (22%) of the four subtypes. The tumor protein 53 (TP53)-active and TP53-inactive types include patients with intermediate prognosis and recurrence rates (with respect to the other two subtypes), with the TP53-active group showing better prognosis. We describe key molecular alterations in each of the four subtypes using targeted sequencing and genome-wide copy number microarrays. We validate these subtypes in independent cohorts in order to provide a consistent and unified framework for further clinical and preclinical translational research.
    No preview · Article · Apr 2015 · Nature medicine
  • [Show abstract] [Hide abstract]
    ABSTRACT: To assess the efficacy and safety of weekly docetaxel plus a fixed-dose rate (FDR) of gemcitabine in metastatic esophageal squamous cell carcinoma (SCC). A multi-center, open-label, prospective phase II study was designed. Thirty-three esophageal SCC patients with documented progression after fluoropyrimidine/platinum-based first-line chemotherapy were enrolled and treated with docetaxel 35 mg/m(2) and gemcitabine 1000 mg/m(2) iv at a FDR (10 mg/m(2) per minute) on days 1 and 8. Treatment was repeated every twenty-one days until disease progression, unacceptable toxicity, or consent withdrawal. The primary endpoint was response rate (RR), and secondary endpoints were safety, progression-free survival (PFS) and overall survival (OS). Combination of weekly docetaxel and FDR gemcitabine was well tolerated: the most common treatment-related adverse events were anemia (97%), fatigue (64%) and neutropenia (55%). One patient with multiple lung and lymph node metastases died of respiratory failure after receiving four cycles of chemotherapy, and the possibility of drug-induced pneumonitis could not be completely excluded. Disease control (objective response plus stable disease) in the ITT population was achieved in 88% of patients, and the overall RR was 30% (95%CI: 15%-46%). The median PFS and OS were 4.0 (95%CI: 3.4-4.6) and 8.8 mo (95%CI: 7.8-9.8 mo), respectively. A combination of weekly docetaxel and FDR gemcitabine showed promising antitumor activity and tolerability in previously treated, metastatic esophageal SCC.
    No preview · Article · Apr 2015
  • [Show abstract] [Hide abstract]
    ABSTRACT: Growth factor receptors, often carrying tyrosine kinase activities in their cytoplasmic domains, are overexpressed in many cancers. Coactivation of receptor tyrosine kinases (RTKs) plays a critical role in tumor response to targeted therapeutics. We examined concomitant overexpression of EGFR and MET in patients with HER2+ and HER2- gastric cancers (GCs). Tissue microarray samples obtained from 1,589 GC patients who received R0 gastrectomy with extensive node dissection and adjuvant chemoradiationtherapy were analyzed by immunohistochemistry and fluorescence in situ hybridization. HER2+ was observed in 169 patients (11%). Out of 169 HER2+ patients, 15 (9%) were EGFR+ and MET+, 29 (17%) were EGFR+, 37 (22%) were MET+, and the remaining 88 patients (52%) were HER2+ only, without concomitant EGFR or MET overexpression. Greater number of overexpressed RTKs correlated with younger age (p<0.001), larger tumor size (p=0.027), intestinal histology (p<0.001), and shorter overall survival (p=0.002). The mean overall survival was 113 months for HER2-/EGFR-/MET- and 63 months for HER2+/EGFR+/MET+ subgroups. Patients with HER2+/EGFR+/MET+ GCs had a substantial risk of death with a hazard ratio of 3.01 (95% CI, 1.54–5.90), compared to HER2-/EGFR-/MET- GC patients. Using patient-derived tumor cell models isolated from pericardial effusion of HER2+ and MET+ GC cases, we demonstrated that the combination of HER2-inhibitor (lapatinib) and MET-inhibitor offered a more profound inhibition in the ERK/AKT pathway and cell proliferation than lapatinib alone. Co-overexpression of RTKs was demonstrated in small subsets of GC associated with aggressive behavior, and in these cases, combination therapy may be considered as potential treatment options. © 2014 Wiley Periodicals, Inc.
    No preview · Article · Apr 2015 · International Journal of Cancer
  • [Show abstract] [Hide abstract]
    ABSTRACT: Clinical benefit from trastuzumab and other anti-human epidermal growth factor receptor-2 (HER2) therapies in patients with HER2-positive gastric cancer (GC) remains limited by primary or acquired resistance. We aimed to investigate the impact of concomitant molecular alterations to HER2 amplification on the clinical outcome of trastuzumab-treated patients. Using immunohistochemistry (IHC), copy number variations (CNVs), and Ion Ampliseq Cancer Panel, we analyzed the status of concomitant alterations in 50 HER2-positive advanced GC patients treated with trastuzumab in combination with other chemotherapeutic agents. The percentage of tumor samples with at least one concomitant alteration was 40% as assessed by IHC, 16% by CNVs, and 64% by Ampliseq sequencing. Median progression-free survival (PFS) was 8.0 months (95% confidence interval, 4.8-11.3). Patients were divided into two subgroups according to PFS values with a cutoff point of 8 months; results show that concomitant genomic alterations do not correlate with trastuzumab response. However, CNVs of CCNE1 significantly correlated (p < 0.05) with a shorter survival time. Our findings indicate that additional alterations implemented for prediction of clinical benefit from HER2-targeting agents in GC remained unclear. Further studies will be needed to elucidate the role of each specific biomarker and to optimize therapeutic approaches.
    No preview · Article · Mar 2015 · Scientific Reports
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We retrospectively reviewed outcomes of treatment with pazopanib, an oral multi-tyrosine kinase angiogenesis inhibitor, in patients with advanced soft tissue sarcoma, a rare and heterogeneous tumor group with limited treatment options. Between 2009 and 2013, 43 patients with metastatic soft tissue sarcoma received pazopanib as salvage chemotherapy after one or more cytotoxic regimens. Response rate, progression-free survival, and overall survival were analyzed according to histological subtype, Eastern Cooperative Oncology Group performance status, and metastatic site. Common histological subtypes included leiomyosarcoma (n = 9), angiosarcoma (n = 6), malignant fibrous histiocytoma/undifferentiated pleomorphic sarcoma (MFH/UPS, n = 5), malignant peripheral nerve sheath tumor (MPNST, n = 5), and synovial sarcoma (n = 4). Nineteen patients (44.2%) received more than two chemotherapy regimens before pazopanib. At the time of analysis, 208 treatment cycles of pazopanib had been administered (median, 4.8 cycles per patient), and no treatment-related mortality occurred. The disease control rate was 61.0% (95% confidence interval [CI], 46.1-75.9%), and the overall response rate was 17.1% (partial response, n = 7; complete response, n = 0). Partial response was achieved in two patients with synovial sarcoma, two with MFH/UPS, one with MPNST, one with leiomyosarcoma, and one with angiosarcoma. The median lengths of progression-free survival and overall survival were 5.0 months (95% CI, 3.6-6.4 months) and 8.2 months (95% CI, 5.8-10.6 months), respectively. Progression-free survival was shorter in the patients with liposarcoma and rhabdomyosarcoma (1.3 and 0.9 months, respectively) than in those with leiomyosarcoma, MPNST, MFH/UPS, and synovial sarcoma (5.6, 6.5, 7.1, and 7.7 months, respectively). Pazopanib demonstrated acceptable antitumor activity in the Asian patients who had been heavily pretreated for sarcoma, with seemingly more favorable results in the patients with leiomyosarcoma, MPNST, MFH/UPS, and synovial sarcoma than in those with liposarcoma and rhabdomyosarcoma.
    Full-text · Article · Mar 2015 · BMC Cancer
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Chromogranin A (CgA) has been considered to be valuable not only in the diagnosis but also in monitoring the disease response to treatment. However, only a few studies have been published on this issue. We purposed to evaluate whether biochemical response using plasma CgA level is reliable in concordance with the clinical response of grade 1-3 nonfunctiong gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Between March 2011 and September 2013, a total of 27 cases in 18 patients were analysed, clinically and radiologically while serial CgA tests were also conducted during treatment. Tumor responses were defined by both RECIST criteria 1.1 and biochemical criteria based on the CgA level. Among the 27 cases analysed, no difference in the basal CgA level was observed with regard to gender, primary tumor site, tumor grade (WHO classification), liver metastasis, number of metastatic site, and line of chemotherapy. The overall response rate (RR) by RECIST criteria 1.1 was 6 out of the 27 cases (22.2%) and 8 out of the 27 cases (29.6%) for biochemical RR. The overall concordance rates of the response based on RECIST and biochemical criteria were 74%. In grades 1 and 2 GEP-NETs (n=17), the concordance rate of the disease control was 94.1%. There was a significant difference for progression free survival (PFS) between responders and non-responder in accordance to biochemical criteria (35.73 months vs. 5.93 months, p=0.05). s This study revealed that changes of the plasma CgA levels were associated with tumour response. Additionally, biochemical response based on serial CgA may be a predictive marker for PFS in GEP-NETs.
    Full-text · Article · Mar 2015 · Neuroendocrinology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Management of gastroenteropancreatic (GEP) neuroendocrine tumors with liver metastases (NETLM) presents many clinical challenges. Assessment of the extent of disease and primary tumor site is crucial for management. In this study, we investigated the primary tumor sites and prognostic factors in GEP NETLM among Korean patients. We reviewed the medical records of 72 Korean patients diagnosed with GEP NETLM between January 1999 and May 2013, focusing on their clinical and pathologic characteristics. The most frequently encountered primary tumor sites were the pancreas (N=25, 35%), stomach (N=8, 11%), gall bladder (N=4, 6%) and rectum (N=3, 4%). Twenty-five patients (35%) had occult primary tumor. Twelve patients (17%) had histological grade G1 tumors, 30 patients (42%) had G2 tumors, and 30 patients (42%) had G3 tumors. The mean follow-up period after histological confirmation of hepatic metastases was 11.30 ± 2.44 months for G3 tumors, 19.67 ± 4.09 months for G2 tumors, and 30.67 ± 6.51 months for G1 tumors. Multivariate analyses revealed that an unknown primary tumor site (P=0.001) and higher histological grade (P<0.001) were independent prognostic indicators for shorter overall survival (OS). Most long-term survivors (OS >24 months) had received antitumor treatment. The primary tumor site most frequently associated with GEP NETLM was the pancreas. Unknown primary tumor and higher histological grade were independent prognostic indicators for shorter OS. Patients identified as being at a risk of shorter OS should be followed closely.
    Preview · Article · Feb 2015 · Cancer Research and Treatment
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We previously reported that the addition of erlotinib to gemcitabine and oxaliplatin (GEMOX) resulted in greater antitumor activity and might be a treatment option for patients with biliary tract cancers (BTCs). Molecular subgroup analysis of treatment outcomes in patients who had specimens available for analysis was undertaken. Epidermal growth factor receptor (EGFR), KRAS, and PIK3CA mutations were evaluated using peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp reactions. Survival and response rates (RRs) were analyzed according to the mutational status. Sixty-four patients (48.1%) were available for mutational analysis in the chemotherapy alone group and 61 (45.1%) in the chemotherapy plus erlotinib group. 1.6% (2/116) harbored an EGFR mutation (2 patients; exon 20), 9.6% (12/121) harbored a KRAS mutation (12 patients; exon 2), and 9.6% (12/118) harbored a PIK3CA mutation (10 patients, exon 9 and 2 patients, exon 20). The addition of erlotinib to GEMOX in patients with KRAS wild-type disease (n = 109) resulted in significant improvements in overall response compared with GEMOX alone (30.2% vs 12.5%, P = .024). In 95 patients with both wild-type KRAS and PIK3CA, there was evidence of a benefit associated with the addition of erlotinib to GEMOX with respect to RR as compared with GEMOX alone (P = .04). This study demonstrates that KRAS mutational status might be considered a predictive biomarker for the response to erlotinib in BTCs. Additionally, the mutation status of PIK3CA may be a determinant for adding erlotinib to chemotherapy in KRAS wild-type BTCs. Copyright © 2014 Neoplasia Press, Inc. Published by Elsevier Inc. All rights reserved.
    Full-text · Article · Feb 2015 · Translational oncology
  • [Show abstract] [Hide abstract]
    ABSTRACT: The Adjuvant Chemoradiotherapy in Stomach Tumors (ARTIST) trial tested whether the addition of radiotherapy to adjuvant chemotherapy improved disease-free survival (DFS) in patients with D2-resected gastric cancer (GC). Between November 2004 and April 2008, 458 patients with GC who received gastrectomy with D2 lymph node dissection were randomly assigned to either six cycles of adjuvant chemotherapy with capecitabine and cisplatin (XP) or to two cycles of XP followed by chemoradiotherapy and then two additional cycles of XP (XPRT). This final update contains the first publication of overall survival (OS), together with updated DFS and subset analyses. With 7 years of follow-up, DFS remained similar between treatment arms (hazard ratio [HR], 0.740; 95% CI, 0.520 to 1.050; P = .0922). OS also was similar (HR, 1.130; 95% CI, 0.775 to 1.647; P = .5272). The effect of the addition of radiotherapy on DFS and OS differed by Lauren classification (interaction P = .04 for DFS; interaction P = .03 for OS) and lymph node ratio (interaction P < .01 for DFS; interaction P < .01 for OS). Subgroup analyses also showed that chemoradiotherapy significantly improved DFS in patients with node-positive disease and with intestinal-type GC. There was a similar trend for DFS and OS by stage of disease. In D2-resected GC, both adjuvant chemotherapy and chemoradiotherapy are tolerated and equally beneficial in preventing relapse. Because results suggest a significant DFS effect of chemoradiotherapy in subsets of patients, the ARTIST 2 trial evaluating adjuvant chemotherapy and chemoradiotherapy in patients with node-positive, D2-resected GC is under way. © 2015 by American Society of Clinical Oncology.
    No preview · Article · Jan 2015 · Journal of Clinical Oncology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To investigate the prognostic role of the estrogen receptor (ER) in gastric cancer (GC) patients, tumor tissues from 932 patients with advanced GC were assessed for ER expression using immunohistochemistry, and their clinicopathologic features were evaluated. Forty patients (4.3%) had ER expression and they were more frequently associated with diffuse type gastric cancer and shorter disease free survival. Furthermore, we carried out in vitro analysis to evaluate the effect of ER modulation on the proliferation of GC cell lines. Estradiol enhanced proliferation of ER positive GC cells while it did not show any effect on ER negative GC cells. When ER was inhibited by fulvestrant and ER siRNA, estradiol-induced proliferation of ER positive GC cell was suppressed. Paclitaxel showed synergistic anti-proliferative impacts with fulvestrant. Suppressing ER by fulvestrant, paclitaxel and ER siRNA showed increased expression of E-cadherin, which is a crucial factor in diffuse-type carcinogenesis.
    Full-text · Article · Dec 2014 · Scientific Reports
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: The granisetron transdermal system (GTS) showed non-inferior efficacy to oral granisetron to control chemotherapy-induced nausea and vomiting (CINV) during multiday chemotherapy. We compared the efficacy and safety of GTS with that of intravenous and oral granisetron in Korean patients receiving moderately emetogenic chemotherapy (MEC). Patients and methods: A total of 276 patients were randomized into GTS (n = 139, one patch on days 1-4) or control group (n = 137, intravenous on day 1 and oral on days 2-4). The primary endpoint was the percentage of patients achieving complete response (CR) from chemotherapy initiation until 24 h after the final administration. Results: Out of 234 patients (112 in GTS and 122 in control group) included in the per protocol analysis, 97.9 % had gastrointestinal cancer and 76.9 % received 3-day chemotherapy. The GTS showed non-inferior efficacy achieving CR in 75.0 % of the patients; 74.6 % of the patients in the control group achieved CR (95 % confidence interval -10.73 to 11.55 %). The CR rate did not change after subgroup analyses by sex, age, and chemotherapy naivety and analysis per day and overall days of treatment. The GTS group showed sustained CR from day 1 to day 4. Patients' satisfaction, assessed using Functional Living Index-Emesis (FLI-E), showed no difference. Both treatments were well tolerated and safe. Conclusion: The GTS showed non-inferior efficacy to intravenous and oral granisetron. The safety, tolerability, and FLI-E scores of the GTS were comparable to those of control group. The GTS offers a convenient alternative option for relieving CINV in patients receiving MEC.
    No preview · Article · Dec 2014 · Supportive Care Cancer
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aims of this study were to demonstrate the tumorigenicity of CD133+ colon cancer cells in vitro, analyze the correlations between spheroid formation and clinicopathologic variables, and screen for overexpressed genes in CD133+ colon cancer stem cells. Moreover, the aim of this study was to establish a living tumor tissue bank using surgically resected specimens. Using LoVo cell line, we isolated CD133+ cells and performed clonogenic assay and animal experiment to test tumorigenicity of CD133+ cells. Twenty-nine surgical samples were freshly collected from 27 patients who received curative or palliative surgery, and the samples were mechanically and enzymatically dissociated into single cells. We confirmed the enhanced tumorigenicity of CD133+ cells isolated from LoVo cell line both in vitro and in vivo. Of these 29 samples, 8 (28%) contained >3% CD133+ cells. Sphere formation was significantly higher in samples from patients with lymphatic invasion than in those without lymphatic invasion [54.5% (6/11) vs. 12.5% (2/16); P=0.033] and in samples containing >3% of CD133+ cells than in those containing ≤3% of CD133+ cells [36.4% (4/11) vs. 0% (0/16); P=0.019]. These findings indicate that CD133 is a valid marker for identifying cancer stem cells from fresh surgically resected colorectal cancer tissues. Furthermore, we successfully established a living tumor tissue bank using surgically resected colorectal tissues with a viability of >70%.
    No preview · Article · Dec 2014 · Journal of gastrointestinal oncology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report updated progression-free survival (PFS) and overall survival (OS) data from a trial that compared capecitabine plus oxaliplatin (CapeOX) versus S-1 plus oxaliplatin (SOX) for the first-line treatment of metastatic colorectal cancer. This trial was a randomized, two-armed, non-inferiority phase 3 comparison of CapeOX (capecitabine 1000 mg/m2 twice daily on days 1-14 and oxaliplatin 130 mg/m2 on day 1) versus SOX (S-1 40mg/m2 twice daily on days 1-14 and oxaliplatin 130 mg/m2 on day 1). The primary end point was to show non-inferiority of SOX relative to CapeOX in terms of PFS. Thus, a follow-up exploratory analysis of PFS and OS was performed. The intention to treat (ITT) population was comprised of 340 patients (SOX arm: 168 and CapeOX arm: 172). The updated median PFS was 7.1 months (95% CI 6.4-8.0) in the SOX group and 6.3 months (95% CI 4.9-6.7) in the CapeOX group (hazard ratio [HR], 0.83 [0.66-1.04], p = .10). The median OS was 19.0 months (95% CI 15.3-23.0) in the SOX group and 18.4 months (95% CI 14.1-20.7) in the CapeOX group (HR, 0.86 [0.68-1.08], p = .19). Subgroup analyses according to principal demographic factors such as sex, age, ECOG (Eastern Cooperative Oncology Group) performance status, primary tumor location, measurability, previous adjuvant therapy, number of metastatic organs, and liver metastases showed no interaction between any of these characteristics and the treatment. Updated survival analysis shows that SOX is similar to CapeOX, confirming the initial PFS analysis. Therefore, the SOX regimen could be an alternative first-line doublet chemotherapy strategy for patients with metastatic colorectal cancer.Trial registration: NCT00677443 and May 12 2008.
    Full-text · Article · Nov 2014 · BMC Cancer
  • [Show abstract] [Hide abstract]
    ABSTRACT: Gastric cancer (GC) is the second most common cause of cancer-related deaths. It is known to be a heterogeneous disease with several molecular and histological subtypes. Here we perform whole-genome sequencing of 49 GCs with diffuse (N=31) and intestinal (N=18) histological subtypes and identify three mutational signatures, impacting TpT, CpG and TpCp[A/T] nucleotides. The diffuse-type GCs show significantly lower clonality and smaller numbers of somatic and structural variants compared with intestinal subtype. We further divide the diffuse subtype into one with infrequent genetic changes/low clonality and another with relatively higher clonality and mutations impacting TpT dinucleotide. Notably, we discover frequent and exclusive mutations in Ephrins and SLIT/ROBO signalling pathway genes. Overall, this study delivers new insights into the mutational heterogeneity underlying distinct histologic subtypes of GC that could have important implications for future research in the diagnosis and treatment of GC.
    No preview · Article · Nov 2014 · Nature Communications
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Patients with gastric and esophageal (GE) adenocarcinoma tumors in which the oncogene ERBB2 has been amplified are routinely treated with a combination of cytotoxic chemotherapy and the ERBB2-directed antibody trastuzumab; however, the addition of trastuzumab, even when tested in a selected biomarker-positive patient population, provides only modest survival gains. To investigate the potential reasons for the modest impact of ERBB2-directed therapies, we explored the hypothesis that secondary molecular features of ERBB2-amplified GE adenocarcinomas attenuate the impact of ERBB2 blockade. We analyzed genomic profiles of ERBB2-amplified GE adenocarcinomas and determined that the majority of ERBB2-amplified tumors harbor secondary oncogenic alterations that have the potential to be therapeutically targeted. These secondary events spanned genes involved in cell-cycle regulation as well as phosphatidylinositol-3 kinase and receptor tyrosine kinase signaling. Using ERBB2-amplified cell lines, we demonstrated that secondary oncogenic events could confer resistance to ERBB2-directed therapies. Moreover, this resistance could be overcome by targeting the secondary oncogene in conjunction with ERBB2-directed therapy. EGFR is commonly coamplified with ERBB2, and in the setting of ERBB2 amplification, higher EGFR expression appears to mark tumors with greater sensitivity to dual EGFR/ERBB2 kinase inhibitors. These data suggest that combination inhibitor strategies, guided by secondary events in ERBB2-amplified GE adenocarcinomas, should be evaluated in clinical trials.
    Full-text · Article · Nov 2014 · Journal of Clinical Investigation
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective Differences in gastric cancer (GC) clinical outcomes between patients in Asian and non-Asian countries has been historically attributed to variability in clinical management. However, recent international Phase III trials suggest that even with standardised treatments, GC outcomes differ by geography. Here, we investigated gene expression differences between Asian and non-Asian GCs, and if these molecular differences might influence clinical outcome. Design We compared gene expression profiles of 1016 GCs from six Asian and three non-Asian GC cohorts, using a two-stage meta-analysis design and a novel biostatistical method (RUV-4) to adjust for technical variation between cohorts. We further validated our findings by computerised immunohistochemical analysis on two independent tissue microarray (TMA) cohorts from Asian and non-Asian localities (n=665). Results Gene signatures differentially expressed between Asians and non-Asian GCs were related to immune function and inflammation. Non-Asian GCs were significantly enriched in signatures related to T-cell biology, including CTLA-4 signalling. Similarly, in the TMA cohorts, non-Asian GCs showed significantly higher expression of T-cell markers (CD3, CD45R0, CD8) and lower expression of the immunosuppressive T-regulatory cell marker FOXP3 compared to Asian GCs (p<0.05). Inflammatory cell markers CD66b and CD68 also exhibited significant cohort differences (p<0.05). Exploratory analyses revealed a significant relationship between tumour immunity factors, geographic locality-specific prognosis, and postchemotherapy outcomes. Conclusions Analyses of >1600 GCs suggest that Asian and non-Asian GCs exhibit distinct tumour immunity signatures related to T-cell function. These differences may influence geographical differences in clinical outcome, and the design of future trials particularly in immuno-oncology.
    Full-text · Article · Nov 2014 · Gut

Publication Stats

4k Citations
901.83 Total Impact Points

Institutions

  • 2005-2015
    • Samsung Medical Center
      • Department of Hematology and Oncology
      Sŏul, Seoul, South Korea
  • 2004-2015
    • Sungkyunkwan University
      • • School of Medicine
      • • Samsung Medical Center
      Sŏul, Seoul, South Korea
  • 2010
    • Hallym University Medical Center
      • Department of Internal Medicine
      Seoul, Seoul, South Korea