21 results on '"Khng AJ"'
Search Results
2. Genomic Insights into Idiopathic Granulomatous Mastitis through Whole-Exome Sequencing: A Case Report of Eight Patients.
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Ong SS, Ho PJ, Khng AJ, Tan BKT, Tan QT, Tan EY, Tan SM, Putti TC, Lim SH, Tang ELS, Li J, and Hartman M
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- Humans, Female, Adult, Mutation, Genomics methods, Middle Aged, Genetic Predisposition to Disease, Granulomatous Mastitis genetics, Granulomatous Mastitis pathology, Granulomatous Mastitis diagnosis, Exome Sequencing
- Abstract
Idiopathic granulomatous mastitis (IGM) is a rare condition characterised by chronic inflammation and granuloma formation in the breast. The aetiology of IGM is unclear. By focusing on the protein-coding regions of the genome, where most disease-related mutations often occur, whole-exome sequencing (WES) is a powerful approach for investigating rare and complex conditions, like IGM. We report WES results on paired blood and tissue samples from eight IGM patients. Samples were processed using standard genomic protocols. Somatic variants were called with two analytical pipelines: nf-core/sarek with Strelka2 and GATK4 with Mutect2 . Our WES study of eight patients did not find evidence supporting a clear genetic component. The discrepancies between variant calling algorithms, along with the considerable genetic heterogeneity observed amongst the eight IGM cases, indicate that common genetic drivers are not readily identifiable. With only three genes, CHIT1 , CEP170 , and CTR9 , recurrently altering in multiple cases, the genetic basis of IGM remains uncertain. The absence of validation for somatic variants by Sanger sequencing raises further questions about the role of genetic mutations in the disease. Other potential contributors to the disease should be explored.
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- 2024
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3. Alterations to DNA methylation patterns induced by chemotherapy treatment are associated with negative impacts on the olfactory pathway.
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Ho PJ, Khng AJ, Tan BK, Lim GH, Tan SM, Tan VKM, Tan RSYC, Lim EH, Iau PT, Chew YJ, Lim YY, Hartman M, Tan EY, and Li J
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- Humans, Female, Olfactory Pathways, CpG Islands, DNA Methylation, Breast Neoplasms
- Abstract
Background: Exposure to cytotoxic chemotherapy treatment may alter DNA methylation (DNAm) in breast cancer patients., Methods: We performed DNAm analysis in 125 breast cancer patients with blood drawn before and after chemotherapy, using the Illumina MethylationEPIC array. DNAm changes of 588,798 individual CpGs (including 41,207 promoter regions) were evaluated using linear regression models adjusted for monocyte proportion. Gene set enrichment analyses (GSEA) were conducted to identify key Gene Ontology (GO) biological processes or Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with chemotherapy. Results were validated in a separate cohort of breast cancer patients who were treated (n = 1273) and not treated (n = 872) by chemotherapy (1808 blood, 337 saliva)., Results: A total of 141 differentially methylated CpGs and 11 promoters were significantly associated with chemotherapy after multiple testing corrections in both the paired sample and single time point analyses. GSEA of promoter regions (pre-ranked by test statistics) identified six suppressed biological processes (p < 4.67e-8) related to sensory perception and detection of chemical stimuli, including smell perception (GO:0007606, GO:0007608, GO:0009593, GO:0050906, GO:0050907, and GO:0050911). The same six biological processes were significantly suppressed in the validation dataset (p < 9.02e-14). The KEGG pathway olfactory transduction (hsa04740) was also found to be significantly suppressed (p
paired-samples = 1.72e-9, psingle-timepoint-blood = 2.03e-15 and psingle-timepoint-saliva = 7.52e-56)., Conclusion: The enrichment of imprinted genes within biological processes and pathways suggests a biological mechanism by which chemotherapy could affect the perception of smell., (© 2023. The Author(s).)- Published
- 2023
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4. Profiling Microbial Communities in Idiopathic Granulomatous Mastitis.
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Ong SS, Xu J, Sim CK, Khng AJ, Ho PJ, Kwan PKW, Ravikrishnan A, Tan KB, Tan QT, Tan EY, Tan SM, Putti TC, Lim SH, Tang ELS, Nagarajan N, Karnani N, Li J, and Hartman M
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- Humans, Female, RNA, Ribosomal, 16S genetics, Immunoglobulin M, Suppuration complications, Granulomatous Mastitis complications, Granulomatous Mastitis microbiology, Microbiota genetics
- Abstract
Idiopathic granulomatous mastitis (IGM) is a rare and benign inflammatory breast disease with ambiguous aetiology. Contrastingly, lactational mastitis (LM) is commonly diagnosed in breastfeeding women. To investigate IGM aetiology, we profiled the microbial flora of pus and skin in patients with IGM and LM. A total of 26 patients with IGM and 6 patients with LM were included in the study. The 16S rRNA sequencing libraries were constructed from 16S rRNA gene amplified from total DNA extracted from pus and skin swabs in patients with IGM and LM controls. Constructed libraries were multiplexed and paired-end sequenced on HiSeq4000. Metagenomic analysis was conducted using modified microbiome abundance analysis suite customised R-resource for paired pus and skin samples. Microbiome multivariable association analyses were performed using linear models. A total of 21 IGM and 3 LM paired pus and skin samples underwent metagenomic analysis. Bray−Curtis ecological dissimilarity distance showed dissimilarity across four sample types (IGM pus, IGM skin, LM pus, and LM skin; PERMANOVA, p < 0.001). No characteristic dominant genus was observed across the IGM samples. The IGM pus samples were more diverse than corresponding IGM skin samples (Shannon and Simpson index; Wilcoxon paired signed-rank tests, p = 0.022 and p = 0.07). Corynebacterium kroppenstedtii, reportedly associated with IGM in the literature, was higher in IGM pus samples than paired skin samples (Wilcoxon, p = 0.022). Three other species and nineteen genera were statistically significant in paired IGM pus−skin comparison after antibiotic treatment adjustment and multiple comparisons correction. Microbial profiles are unique between patients with IGM and LM. Inter-patient variability and polymicrobial IGM pus samples cannot implicate specific genus or species as an infectious cause for IGM.
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- 2023
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5. Relevance of the MHC region for breast cancer susceptibility in Asians.
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Ho PJ, Khng AJ, Tan BK, Tan EY, Tan SM, Tan VKM, Lim GH, Aronson KJ, Chan TL, Choi JY, Dennis J, Ho WK, Hou MF, Ito H, Iwasaki M, John EM, Kang D, Kim SW, Kurian AW, Kwong A, Lophatananon A, Matsuo K, Mohd-Taib NA, Muir K, Murphy RA, Park SK, Shen CY, Shu XO, Teo SH, Wang Q, Yamaji T, Zheng W, Bolla MK, Dunning AM, Easton DF, Pharoah PDP, Hartman M, and Li J
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- Alleles, Asian People genetics, Female, Genetic Predisposition to Disease, Genotype, Humans, Polymorphism, Single Nucleotide, Breast Neoplasms genetics, HLA Antigens genetics
- Abstract
Background: Human leukocyte antigen (HLA) genes play critical roles in immune surveillance, an important defence against tumors. Imputing HLA genotypes from existing single-nucleotide polymorphism datasets is low-cost and efficient. We investigate the relevance of the major histocompatibility complex region in breast cancer susceptibility, using imputed class I and II HLA alleles, in 25,484 women of Asian ancestry., Methods: A total of 12,901 breast cancer cases and 12,583 controls from 12 case-control studies were included in our pooled analysis. HLA imputation was performed using SNP2HLA on 10,886 quality-controlled variants within the 15-55 Mb region on chromosome 6. HLA alleles (n = 175) with info scores greater than 0.8 and frequencies greater than 0.01 were included (resolution at two-digit level: 71; four-digit level: 104). We studied the associations between HLA alleles and breast cancer risk using logistic regression, adjusting for population structure and age. Associations between HLA alleles and the risk of subtypes of breast cancer (ER-positive, ER-negative, HER2-positive, HER2-negative, early-stage, and late-stage) were examined., Results: We did not observe associations between any HLA allele and breast cancer risk at P < 5e-8; the smallest p value was observed for HLA-C*12:03 (OR = 1.29, P = 1.08e-3). Ninety-five percent of the effect sizes (OR) observed were between 0.90 and 1.23. Similar results were observed when different subtypes of breast cancer were studied (95% of ORs were between 0.85 and 1.18)., Conclusions: No imputed HLA allele was associated with breast cancer risk in our large Asian study. Direct measurement of HLA gene expressions may be required to further explore the associations between HLA genes and breast cancer risk., (© 2022. The Author(s).)
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- 2022
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6. Mammography screening is associated with more favourable breast cancer tumour characteristics and better overall survival: case-only analysis of 3739 Asian breast cancer patients.
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Lim ZL, Ho PJ, Khng AJ, Yeoh YS, Ong ATW, Tan BKT, Tan EY, Tan SM, Lim GH, Lee JA, Tan VK, Hu J, Li J, and Hartman M
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- Cohort Studies, Female, Humans, Mammography, Mass Screening, Breast Neoplasms diagnostic imaging, Early Detection of Cancer
- Abstract
Background: Early detection of breast cancer (BC) through mammography screening (MAM) is known to reduce mortality. We examined the differential effect that mammography has on BC characteristics and overall survival and the sociodemographic determinants of MAM utilization in a multi-ethnic Asian population., Methods: This study included 3739 BC patients from the Singapore Breast Cancer Cohort (2010-2018). Self-reported sociodemographic characteristics were collected using a structured questionnaire. Clinical data were obtained through medical records. Patients were classified as screeners (last screening mammogram ≤ 2 years before diagnosis), non-screeners (aware but did not attend or last screen > 2years), and those unaware of MAM. Associations between MAM behaviour (MB) and sociodemographic factors and MB and tumour characteristics were examined using multinomial regression. Ten-year overall survival was modelled using Cox regression., Results: Patients unaware of screening were more likely diagnosed with late stage (OR
stage III vs stage I (Ref) [95% CI]: 4.94 [3.45-7.07], p < 0.001), high grade (ORpoorly vs well-differentiated (reference) : 1.53 [1.06-2.20], p = 0.022), nodal-positive, large size (OR>5cm vs ≤2cm (reference) : 5.06 [3.10-8.25], p < 0.001), and HER2-positive tumours (ORHER2-negative vs HER2-positive (reference) : 0.72 [0.53-0.97], p = 0.028). Similar trends were observed between screeners and non-screeners with smaller effect sizes. Overall survival was significantly shorter than screeners in the both groups (HRnon-screeners : 1.89 [1.22-2.94], p = 0.005; HRunaware : 2.90 [1.69-4.98], p < 0.001). Non-screeners and those unaware were less health conscious, older, of Malay ethnicity, less highly educated, of lower socioeconomic status, more frequently ever smokers, and less physically active. Among screeners, there were more reported personal histories of benign breast surgeries or gynaecological conditions and positive family history of breast cancer., Conclusions: Mammography attendance is associated with more favourable BC characteristics and overall survival. Disparities in the utility of MAM services suggest that different strategies may be needed to improve MAM uptake., (© 2022. The Author(s).)- Published
- 2022
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7. Association between Breast Cancer Polygenic Risk Score and Chemotherapy-Induced Febrile Neutropenia: Null Results.
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Ong SS, Ho PJ, Khng AJ, Lim EH, Wong FY, Tan BK, Lim SH, Tan EY, Tan SM, Tan VKM, Dent R, Tan TJY, Ngeow J, Madhukumar P, Hamzah JLB, Sim Y, Lim GH, Pang JS, Alcantara VS, Chan PMY, Chen JJC, Kuah S, Seah JCM, Buhari SA, Tang SW, Ng CWQ, Li J, and Hartman M
- Abstract
Background: The hypothesis that breast cancer (BC) susceptibility variants are linked to chemotherapy-induced toxicity has been previously explored. Here, we investigated the association between a validated 313-marker-based BC polygenic risk score (PRS) and chemotherapy-induced neutropenia without fever and febrile neutropenia (FNc) in Asian BC patients., Methods: This observational case-control study of Asian BC patients treated with chemotherapy included 161 FNc patients, 219 neutropenia patients, and 936 patients who did not develop neutropenia. A continuous PRS was calculated by summing weighted risk alleles associated with overall, estrogen receptor- (ER-) positive, and ER-negative BC risk. PRS distributions neutropenia or FNc cases were compared to controls who did not develop neutropenia using two-sample t -tests. Odds ratios (OR) and corresponding 95% confidence intervals were estimated for the associations between PRS (quartiles and per standard deviation (SD) increase) and neutropenia-related outcomes compared to controls., Results: PRS distributions were not significantly different in any of the comparisons. Higher PRS
overall quartiles were negatively correlated with neutropenia or FNc. However, the associations were not statistically significant (PRS per SD increase OR neutropenia: 0.91 [0.79-1.06]; FNc: 0.87 [0.73-1.03]). No dose-dependent trend was observed for the ER-positive weighted PRS (PRSER-pos ) and ER-negative weighted PRS (PRSER-neg )., Conclusion: BC PRS was not strongly associated with chemotherapy-induced neutropenia or FNc.- Published
- 2022
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8. Predicting the Likelihood of Carrying a BRCA1 or BRCA2 Mutation in Asian Patients With Breast Cancer.
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Ang BH, Ho WK, Wijaya E, Kwan PY, Ng PS, Yoon SY, Hasan SN, Lim JMC, Hassan T, Tai MC, Allen J, Lee A, Taib NAM, Yip CH, Hartman M, Lim SH, Tan EY, Tan BKT, Tan SM, Tan VKM, Ho PJ, Khng AJ, Dunning AM, Li J, Easton DF, Antoniou AC, and Teo SH
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- BRCA1 Protein genetics, BRCA2 Protein genetics, Cross-Sectional Studies, Female, Genes, BRCA2, Genetic Predisposition to Disease, Germ-Line Mutation, Humans, Middle Aged, Mutation, Breast Neoplasms genetics, Breast Neoplasms pathology, Ovarian Neoplasms genetics
- Abstract
Purpose: With the development of poly (ADP-ribose) polymerase inhibitors for treatment of patients with cancer with an altered BRCA1 or BRCA2 gene, there is an urgent need to ensure that there are appropriate strategies for identifying mutation carriers while balancing the increased demand for and cost of cancer genetics services. To date, the majority of mutation prediction tools have been developed in women of European descent where the age and cancer-subtype distributions are different from that in Asian women., Methods: In this study, we built a new model (Asian Risk Calculator) for estimating the likelihood of carrying a pathogenic variant in BRCA1 or BRCA2 gene, using germline BRCA genetic testing results in a cross-sectional population-based study of 8,162 Asian patients with breast cancer. We compared the model performance to existing mutation prediction models. The models were evaluated for discrimination and calibration., Results: Asian Risk Calculator included age of diagnosis, ethnicity, bilateral breast cancer, tumor biomarkers, and family history of breast cancer or ovarian cancer as predictors. The inclusion of tumor grade improved significantly the model performance. The full model was calibrated (Hosmer-Lemeshow P value = .614) and discriminated well between BRCA and non- BRCA pathogenic variant carriers (area under receiver operating curve, 0.80; 95% CI, 0.75 to 0.84). Addition of grade to the existing clinical genetic testing criteria targeting patients with breast cancer age younger than 45 years reduced the proportion of patients referred for genetic counseling and testing from 37% to 33% ( P value = .003), thereby improving the overall efficacy., Conclusion: Population-specific customization of mutation prediction models and clinical genetic testing criteria improved the accuracy of BRCA mutation prediction in Asian patients., Competing Interests: Andrew LeeEmployment: IlluminaPatents, Royalties, Other Intellectual Property: I am an inventor of the BOADICEA model that is licensed to Cambridge Enterprise (part of the University of Cambridge) for commercialization. I have received royalties from Cambridge Enterprise Nur Aishah Mohd TaibConsulting or Advisory Role: Roche, AstraZeneca, MSD Veronique K.M. TanHonoraria: AstraZeneca (Inst), Roche (Inst)Consulting or Advisory Role: Bertis (Inst) Douglas F. EastonPatents, Royalties, Other Intellectual Property: Royalties from Boadicea risk prediction tool (Inst) Antonis C. AntoniouPatents, Royalties, Other Intellectual Property: Inventor of the BOADICEA model, which has been licensed to Cambridge Enterprise for commercialization. I may receive royalties if commercialization is realized (Inst) Soo Hwang TeoSpeakers' Bureau: AstraZeneca, Pfizer, RocheNo other potential conflicts of interest were reported.
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- 2022
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9. Overlap of high-risk individuals predicted by family history, and genetic and non-genetic breast cancer risk prediction models: implications for risk stratification.
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Ho PJ, Ho WK, Khng AJ, Yeoh YS, Tan BK, Tan EY, Lim GH, Tan SM, Tan VKM, Yip CH, Mohd-Taib NA, Wong FY, Lim EH, Ngeow J, Chay WY, Leong LCH, Yong WS, Seah CM, Tang SW, Ng CWQ, Yan Z, Lee JA, Rahmat K, Islam T, Hassan T, Tai MC, Khor CC, Yuan JM, Koh WP, Sim X, Dunning AM, Bolla MK, Antoniou AC, Teo SH, Li J, and Hartman M
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- Asian People, Female, Genetic Predisposition to Disease genetics, Humans, Risk Assessment, Breast Neoplasms diagnosis, Breast Neoplasms epidemiology, Breast Neoplasms genetics
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Background: Family history, and genetic and non-genetic risk factors can stratify women according to their individual risk of developing breast cancer. The extent of overlap between these risk predictors is not clear., Methods: In this case-only analysis involving 7600 Asian breast cancer patients diagnosed between age 30 and 75 years, we examined identification of high-risk patients based on positive family history, the Gail model 5-year absolute risk [5yAR] above 1.3%, breast cancer predisposition genes (protein-truncating variants [PTV] in ATM, BRCA1, BRCA2, CHEK2, PALB2, BARD1, RAD51C, RAD51D, or TP53), and polygenic risk score (PRS) 5yAR above 1.3%., Results: Correlation between 5yAR (at age of diagnosis) predicted by PRS and the Gail model was low (r=0.27). Fifty-three percent of breast cancer patients (n=4041) were considered high risk by one or more classification criteria. Positive family history, PTV carriership, PRS, or the Gail model identified 1247 (16%), 385 (5%), 2774 (36%), and 1592 (21%) patients who were considered at high risk, respectively. In a subset of 3227 women aged below 50 years, the four models studied identified 470 (15%), 213 (7%), 769 (24%), and 325 (10%) unique patients who were considered at high risk, respectively. For younger women, PRS and PTVs together identified 745 (59% of 1276) high-risk individuals who were not identified by the Gail model or family history., Conclusions: Family history and genetic and non-genetic risk stratification tools have the potential to complement one another to identify women at high risk., (© 2022. The Author(s).)
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- 2022
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10. BREAst screening Tailored for HEr (BREATHE)-A study protocol on personalised risk-based breast cancer screening programme.
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Liu J, Ho PJ, Tan THL, Yeoh YS, Chew YJ, Mohamed Riza NK, Khng AJ, Goh SA, Wang Y, Oh HB, Chin CH, Kwek SC, Zhang ZP, Ong DLS, Quek ST, Tan CC, Wee HL, Li J, Iau PTC, and Hartman M
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- Cohort Studies, Early Detection of Cancer methods, Female, Humans, Mammography methods, Mass Screening, Breast Neoplasms diagnosis, Breast Neoplasms genetics, Breast Neoplasms prevention & control
- Abstract
Routine mammography screening is currently the standard tool for finding cancers at an early stage, when treatment is most successful. Current breast screening programmes are one-size-fits-all which all women above a certain age threshold are encouraged to participate. However, breast cancer risk varies by individual. The BREAst screening Tailored for HEr (BREATHE) study aims to assess acceptability of a comprehensive risk-based personalised breast screening in Singapore. Advancing beyond the current age-based screening paradigm, BREATHE integrates both genetic and non-genetic breast cancer risk prediction tools to personalise screening recommendations. BREATHE is a cohort study targeting to recruit ~3,500 women. The first recruitment visit will include questionnaires and a buccal cheek swab. After receiving a tailored breast cancer risk report, participants will attend an in-person risk review, followed by a final session assessing the acceptability of our risk stratification programme. Risk prediction is based on: a) Gail model (non-genetic), b) mammographic density and recall, c) BOADICEA predictions (breast cancer predisposition genes), and d) breast cancer polygenic risk score. For national implementation of personalised risk-based breast screening, exploration of the acceptability within the target populace is critical, in addition to validated predication tools. To our knowledge, this is the first study to implement a comprehensive risk-based mammography screening programme in Asia. The BREATHE study will provide essential data for policy implementation which will transform the health system to deliver a better health and healthcare outcomes., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2022
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11. Associations between Pre-Diagnostic Physical Activity with Breast Cancer Characteristics and Survival.
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Lim ZL, Lim GH, Ho PJ, Khng AJ, Yeoh YS, Ong ATW, Tan BKT, Tan EY, Tan SM, Tan VK, Li J, and Hartman M
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Physical activity (PA) is known to reduce breast cancer (BC) risk and improve patient prognosis. However, the association between pre-diagnostic PA and the aggressiveness of BC is unclear. We investigated the associations between PA, BC tumour characteristics, and survival. This retrospective observational study included 7688 BC patients from the Singapore Breast Cancer Cohort (2010−2016). PA information from the questionnaire included intensity (light/moderate/vigorous) and duration (<1 h/1−2 h/>2 h per week). A PA score (1−5) incorporating intensity and duration was calculated. Associations between PA score and tumour characteristics such as stage, histological grade, nodal and hormone receptor status were examined using multinomial regression. Moreover, 10-year overall survival was estimated using Cox regression analysis in 6572 patients after excluding patients with invalid survival data and stage IV disease. Breast tumours associated with higher PA score were more likely to be non-invasive (ORinvasive vs. non-invasive(reference) [95% CI]: 0.71 [0.58−0.87], p-trend = 0.001), of lower grade (ORpoorly vs. well differentiated(reference): 0.69 [0.52−0.93], p = 0.014), ER-positive (ORER-negative vs. ER-positive(reference): 0.94 [0.89−1.00], p-trend = 0.049), PR-positive (ORPR-negative vs. PR-positive(reference): 0.82 [0.67−0.99], p = 0.041), HER2-negative (ORHER2-negative vs. HER2-positive(reference): 1.29 [1.02−1.62], p-trend = 0.002), and less likely to be of HER2-overexpressed subtype (ORHER2-overexpressed vs. Luminal A(reference): 0.89 [0.81−0.98], p-trend = 0.018). These associations (odds ratios) were more pronounced among post-menopausal patients. A higher PA score did not improve survival. Higher levels of pre-diagnostic PA were associated with less aggressive tumours in BC patients. This illustrated another benefit of PA in addition to its known role in BC risk reduction.
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- 2022
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12. Germline breast cancer susceptibility genes, tumor characteristics, and survival.
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Ho PJ, Khng AJ, Loh HW, Ho WK, Yip CH, Mohd-Taib NA, Tan VKM, Tan BK, Tan SM, Tan EY, Lim SH, Jamaris S, Sim Y, Wong FY, Ngeow J, Lim EH, Tai MC, Wijaya EA, Lee SC, Chan CW, Buhari SA, Chan PMY, Chen JJC, Seah JCM, Lee WP, Mok CW, Lim GH, Woo E, Kim SW, Lee JW, Lee MH, Park SK, Dunning AM, Easton DF, Schmidt MK, Teo SH, Li J, and Hartman M
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- BRCA1 Protein genetics, Female, Genetic Predisposition to Disease, Genetic Testing, Germ Cells, Germ-Line Mutation, Humans, Odds Ratio, Breast Neoplasms pathology
- Abstract
Background: Mutations in certain genes are known to increase breast cancer risk. We study the relevance of rare protein-truncating variants (PTVs) that may result in loss-of-function in breast cancer susceptibility genes on tumor characteristics and survival in 8852 breast cancer patients of Asian descent., Methods: Gene panel sequencing was performed for 34 known or suspected breast cancer predisposition genes, of which nine genes (ATM, BRCA1, BRCA2, CHEK2, PALB2, BARD1, RAD51C, RAD51D, and TP53) were associated with breast cancer risk. Associations between PTV carriership in one or more genes and tumor characteristics were examined using multinomial logistic regression. Ten-year overall survival was estimated using Cox regression models in 6477 breast cancer patients after excluding older patients (≥75years) and stage 0 and IV disease., Results: PTV
9genes carriership (n = 690) was significantly associated (p < 0.001) with more aggressive tumor characteristics including high grade (poorly vs well-differentiated, odds ratio [95% confidence interval] 3.48 [2.35-5.17], moderately vs well-differentiated 2.33 [1.56-3.49]), as well as luminal B [HER-] and triple-negative subtypes (vs luminal A 2.15 [1.58-2.92] and 2.85 [2.17-3.73], respectively), adjusted for age at diagnosis, study, and ethnicity. Associations with grade and luminal B [HER2-] subtype remained significant after excluding BRCA1/2 carriers. PTV25genes carriership (n = 289, excluding carriers of the nine genes associated with breast cancer) was not associated with tumor characteristics. However, PTV25genes carriership, but not PTV9genes carriership, was suggested to be associated with worse 10-year overall survival (hazard ratio [CI] 1.63 [1.16-2.28])., Conclusions: PTV9genes carriership is associated with more aggressive tumors. Variants in other genes might be associated with the survival of breast cancer patients. The finding that PTV carriership is not just associated with higher breast cancer risk, but also more severe and fatal forms of the disease, suggests that genetic testing has the potential to provide additional health information and help healthy individuals make screening decisions., (© 2021. The Author(s).)- Published
- 2021
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13. Integrative Profiling of T790M-Negative EGFR-Mutated NSCLC Reveals Pervasive Lineage Transition and Therapeutic Opportunities.
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Chua KP, Teng YHF, Tan AC, Takano A, Alvarez JJS, Nahar R, Rohatgi N, Lai GGY, Aung ZW, Yeong JPS, Lim KH, Naeini MM, Kassam I, Jain A, Tan WL, Gogna A, Too CW, Kanesvaran R, Ng QS, Ang MK, Rajasekaran T, Anantham D, Phua GC, Tan BS, Lee YY, Wang L, Teo ASM, Khng AJ, Lim MJ, Suteja L, Toh CK, Lim WT, Iyer NG, Tam WL, Tan EH, Zhai W, Hillmer AM, Skanderup AJ, and Tan DSW
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- ErbB Receptors genetics, Humans, Protein-Tyrosine Kinases genetics, Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Non-Small-Cell Lung genetics, Lung Neoplasms drug therapy, Lung Neoplasms genetics, Mutation
- Abstract
Purpose: Despite the established role of EGFR tyrosine kinase inhibitors (TKIs) in EGFR -mutated NSCLC, drug resistance inevitably ensues, with a paucity of treatment options especially in EGFR
T790M -negative resistance., Experimental Design: We performed whole-exome and transcriptome analysis of 59 patients with first- and second-generation EGFR TKI-resistant metastatic EGFR -mutated NSCLC to characterize and compare molecular alterations mediating resistance in T790M-positive (T790M+ ) and -negative (T790M- ) disease., Results: Transcriptomic analysis revealed ubiquitous loss of adenocarcinoma lineage gene expression in T790M- tumors, orthogonally validated using multiplex IHC. There was enrichment of genomic features such as TP53 alterations, 3q chromosomal amplifications, whole-genome doubling and nonaging mutational signatures in T790M- tumors. Almost half of resistant tumors were further classified as immunehot , with clinical outcomes conditional on immune cell-infiltration state and T790M status. Finally, using a Bayesian statistical approach, we explored how T790M- and T790M+ disease might be predicted using comprehensive genomic and transcriptomic profiles of treatment-naïve patients., Conclusions: Our results illustrate the interplay between genetic alterations, cell lineage plasticity, and immune microenvironment in shaping divergent TKI resistance and outcome trajectories in EGFR -mutated NSCLC. Genomic and transcriptomic profiling may facilitate the design of bespoke therapeutic approaches tailored to a tumor's adaptive potential., (©2021 The Authors; Published by the American Association for Cancer Research.)- Published
- 2021
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14. DNA methylation and breast cancer-associated variants.
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Ho PJ, Dorajoo R, Ivanković I, Ong SS, Khng AJ, Tan BK, Tan VKM, Lim SH, Tan EY, Tan SM, Tan QT, Yan Z, Ngeow J, Sim Y, Chan P, Chuan JCJ, Chan CW, Tang SW, Hartman M, and Li J
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- Adolescent, Child, Female, Genome-Wide Association Study, Humans, Middle Aged, Multifactorial Inheritance, Polymorphism, Single Nucleotide, Quantitative Trait Loci, Breast Neoplasms epidemiology, Breast Neoplasms genetics, DNA Methylation
- Abstract
Background: A breast cancer polygenic risk score (PRS) comprising 313 common variants reliably predicts disease risk. We examined possible relationships between genetic variation, regulation, and expression to clarify the molecular alterations associated with these variants., Methods: Genome-wide methylomic variation was quantified (MethylationEPIC) in Asian breast cancer patients (1152 buffy coats from peripheral whole blood). DNA methylation (DNAm) quantitative trait loci (mQTL) mapping was performed for 235 of the 313 variants with minor allele frequencies > 5%. Stability of identified mQTLs (p < 5e-8) across lifetime was examined using a public mQTL database. Identified mQTLs were also mapped to expression quantitative trait loci (eQTLs) in the Genotype-Tissue Expression Project and the eQTLGen Consortium., Results: Breast cancer PRS was not associated with DNAm. A higher proportion of significant cis-mQTLs were observed. Of 822 significant cis-mQTLs (179 unique variants) identified in our dataset, 141 (59 unique variants) were significant (p < 5e-8) in a public mQTL database. Eighty-six percent (121/141) of the matched mQTLs were consistent at multiple time points (birth, childhood, adolescence, pregnancy, middle age, post-diagnosis, or treatment). Ninety-three variants associated with DNAm were also cis-eQTLs (35 variants not genome-wide significant). Multiple loci in the breast cancer PRS are associated with DNAm, contributing to the polygenic nature of the disease. These mQTLs are mostly stable over time., Conclusions: Consistent results from DNAm and expression data may reveal new candidate genes not previously associated with breast cancer., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
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- 2021
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15. Sequencing of E. coli strain UTI89 on multiple sequencing platforms.
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Fenlon SN, Chee YC, Chee JLY, Choy YH, Khng AJ, Liow LT, Mehershahi KS, Ruan X, Turner SW, Yao F, and Chen SL
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- Escherichia coli genetics, High-Throughput Nucleotide Sequencing, Humans, Escherichia coli Infections, Escherichia coli Proteins genetics, Urinary Tract Infections
- Abstract
Objectives: The availability of matched sequencing data for the same sample across different sequencing platforms is a necessity for validation and effective comparison of sequencing platforms. A commonly sequenced sample is the lab-adapted MG1655 strain of Escherichia coli; however, this strain is not fully representative of more complex and dynamic genomes of pathogenic E. coli strains., Data Description: We present six new sequencing data sets for another E. coli strain, UTI89, which is an extraintestinal pathogenic strain isolated from a patient suffering from a urinary tract infection. We now provide matched whole genome sequencing data generated using the PacBio RSII, Oxford Nanopore MinION R9.4, Ion Torrent, ABI SOLiD, and Illumina NextSeq sequencers. Together with other publically available datasets, UTI89 has a nearly complete suite of data generated on most second- and third-generation sequencers. These data can be used as an additional validation set for new sequencing technologies and analytical methods. More than being another E. coli strain, however, UTI89 is pathogenic, with a 10% larger genome, additional pathogenicity islands, and a large plasmid, features that are common among other naturally occurring and disease-causing E. coli isolates. These data therefore provide a more medically relevant test set for development of algorithms.
- Published
- 2020
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16. An integrative model of pathway convergence in genetically heterogeneous blast crisis chronic myeloid leukemia.
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Ko TK, Javed A, Lee KL, Pathiraja TN, Liu X, Malik S, Soh SX, Heng XT, Takahashi N, Tan JHJ, Bhatia R, Khng AJ, Chng WJ, Sia YY, Fruman DA, Ng KP, Chan ZE, Xie KJ, Hoi Q, Chan CX, Teo ASM, Velazquez Camacho O, Meah WY, Khor CC, Ong CTJ, Soon WJW, Tan P, Ng PC, Chuah C, Hillmer AM, and Ong ST
- Subjects
- Cell Differentiation, Chromatin Immunoprecipitation, DNA Methylation, Datasets as Topic, Enhancer of Zeste Homolog 2 Protein physiology, Gene Dosage, Gene Ontology, High-Throughput Nucleotide Sequencing, Humans, Leukemia, Myelogenous, Chronic, BCR-ABL Positive genetics, Mutation, Polycomb Repressive Complex 1 genetics, Polycomb Repressive Complex 2 genetics, Transcriptome, Exome Sequencing, Whole Genome Sequencing, Blast Crisis genetics, Gene Expression Regulation, Leukemic genetics, Leukemia, Myelogenous, Chronic, BCR-ABL Positive pathology, Polycomb Repressive Complex 1 physiology, Polycomb Repressive Complex 2 physiology
- Abstract
Targeted therapies against the BCR-ABL1 kinase have revolutionized treatment of chronic phase (CP) chronic myeloid leukemia (CML). In contrast, management of blast crisis (BC) CML remains challenging because BC cells acquire complex molecular alterations that confer stemness features to progenitor populations and resistance to BCR-ABL1 tyrosine kinase inhibitors. Comprehensive models of BC transformation have proved elusive because of the rarity and genetic heterogeneity of BC, but are important for developing biomarkers predicting BC progression and effective therapies. To better understand BC, we performed an integrated multiomics analysis of 74 CP and BC samples using whole-genome and exome sequencing, transcriptome and methylome profiling, and chromatin immunoprecipitation followed by high-throughput sequencing. Employing pathway-based analysis, we found the BC genome was significantly enriched for mutations affecting components of the polycomb repressive complex (PRC) pathway. While transcriptomically, BC progenitors were enriched and depleted for PRC1- and PRC2-related gene sets respectively. By integrating our data sets, we determined that BC progenitors undergo PRC-driven epigenetic reprogramming toward a convergent transcriptomic state. Specifically, PRC2 directs BC DNA hypermethylation, which in turn silences key genes involved in myeloid differentiation and tumor suppressor function via so-called epigenetic switching, whereas PRC1 represses an overlapping and distinct set of genes, including novel BC tumor suppressors. On the basis of these observations, we developed an integrated model of BC that facilitated the identification of combinatorial therapies capable of reversing BC reprogramming (decitabine+PRC1 inhibitors), novel PRC-silenced tumor suppressor genes (NR4A2), and gene expression signatures predictive of disease progression and drug resistance in CP., (© 2020 by The American Society of Hematology.)
- Published
- 2020
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17. ALPK1 missense pathogenic variant in five families leads to ROSAH syndrome, an ocular multisystem autosomal dominant disorder.
- Author
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Williams LB, Javed A, Sabri A, Morgan DJ, Huff CD, Grigg JR, Heng XT, Khng AJ, Hollink IHIM, Morrison MA, Owen LA, Anderson K, Kinard K, Greenlees R, Novacic D, Nida Sen H, Zein WM, Rodgers GM, Vitale AT, Haider NB, Hillmer AM, Ng PC, Shankaracharya, Cheng A, Zheng L, Gillies MC, van Slegtenhorst M, van Hagen PM, Missotten TOAR, Farley GL, Polo M, Malatack J, Curtin J, Martin F, Arbuckle S, Alexander SI, Chircop M, Davila S, Digre KB, Jamieson RV, and DeAngelis MM
- Subjects
- Exome genetics, Female, Heterozygote, Humans, Hypohidrosis genetics, Hypohidrosis pathology, Male, Migraine Disorders genetics, Migraine Disorders pathology, Mutation, Missense genetics, Optic Nerve metabolism, Pedigree, Phenotype, Retina pathology, Retinal Dystrophies pathology, Splenomegaly genetics, Splenomegaly pathology, Optic Nerve pathology, Protein Kinases genetics, Retina metabolism, Retinal Dystrophies genetics
- Abstract
Purpose: To identify the molecular cause in five unrelated families with a distinct autosomal dominant ocular systemic disorder we called ROSAH syndrome due to clinical features of retinal dystrophy, optic nerve edema, splenomegaly, anhidrosis, and migraine headache., Methods: Independent discovery exome and genome sequencing in families 1, 2, and 3, and confirmation in families 4 and 5. Expression of wild-type messenger RNA and protein in human and mouse tissues and cell lines. Ciliary assays in fibroblasts from affected and unaffected family members., Results: We found the heterozygous missense variant in the ɑ-kinase gene, ALPK1, (c.710C>T, [p.Thr237Met]), segregated with disease in all five families. All patients shared the ROSAH phenotype with additional low-grade ocular inflammation, pancytopenia, recurrent infections, and mild renal impairment in some. ALPK1 was notably expressed in retina, retinal pigment epithelium, and optic nerve, with immunofluorescence indicating localization to the basal body of the connecting cilium of the photoreceptors, and presence in the sweat glands. Immunocytofluorescence revealed expression at the centrioles and spindle poles during metaphase, and at the base of the primary cilium. Affected family member fibroblasts demonstrated defective ciliogenesis., Conclusion: Heterozygosity for ALPK1, p.Thr237Met leads to ROSAH syndrome, an autosomal dominant ocular systemic disorder.
- Published
- 2019
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18. Bystander CD8 + T cells are abundant and phenotypically distinct in human tumour infiltrates.
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Simoni Y, Becht E, Fehlings M, Loh CY, Koo SL, Teng KWW, Yeong JPS, Nahar R, Zhang T, Kared H, Duan K, Ang N, Poidinger M, Lee YY, Larbi A, Khng AJ, Tan E, Fu C, Mathew R, Teo M, Lim WT, Toh CK, Ong BH, Koh T, Hillmer AM, Takano A, Lim TKH, Tan EH, Zhai W, Tan DSW, Tan IB, and Newell EW
- Subjects
- Antigens, Neoplasm immunology, Antigens, Viral immunology, Apyrase analysis, Apyrase deficiency, Apyrase metabolism, CD8-Positive T-Lymphocytes metabolism, Cell Separation, Colorectal Neoplasms genetics, ErbB Receptors genetics, Humans, Lung Neoplasms genetics, Lymphocytes, Tumor-Infiltrating metabolism, Phenotype, Bystander Effect immunology, CD8-Positive T-Lymphocytes cytology, CD8-Positive T-Lymphocytes immunology, Colorectal Neoplasms immunology, Lung Neoplasms immunology, Lymphocytes, Tumor-Infiltrating cytology, Lymphocytes, Tumor-Infiltrating immunology
- Abstract
Various forms of immunotherapy, such as checkpoint blockade immunotherapy, are proving to be effective at restoring T cell-mediated immune responses that can lead to marked and sustained clinical responses, but only in some patients and cancer types
1-4 . Patients and tumours may respond unpredictably to immunotherapy partly owing to heterogeneity of the immune composition and phenotypic profiles of tumour-infiltrating lymphocytes (TILs) within individual tumours and between patients5,6 . Although there is evidence that tumour-mutation-derived neoantigen-specific T cells play a role in tumour control2,4,7-10 , in most cases the antigen specificities of phenotypically diverse tumour-infiltrating T cells are largely unknown. Here we show that human lung and colorectal cancer CD8+ TILs can not only be specific for tumour antigens (for example, neoantigens), but also recognize a wide range of epitopes unrelated to cancer (such as those from Epstein-Barr virus, human cytomegalovirus or influenza virus). We found that these bystander CD8+ TILs have diverse phenotypes that overlap with tumour-specific cells, but lack CD39 expression. In colorectal and lung tumours, the absence of CD39 in CD8+ TILs defines populations that lack hallmarks of chronic antigen stimulation at the tumour site, supporting their classification as bystanders. Expression of CD39 varied markedly between patients, with some patients having predominantly CD39- CD8+ TILs. Furthermore, frequencies of CD39 expression among CD8+ TILs correlated with several important clinical parameters, such as the mutation status of lung tumour epidermal growth factor receptors. Our results demonstrate that not all tumour-infiltrating T cells are specific for tumour antigens, and suggest that measuring CD39 expression could be a straightforward way to quantify or isolate bystander T cells.- Published
- 2018
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19. Elucidating the genomic architecture of Asian EGFR-mutant lung adenocarcinoma through multi-region exome sequencing.
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Nahar R, Zhai W, Zhang T, Takano A, Khng AJ, Lee YY, Liu X, Lim CH, Koh TPT, Aung ZW, Lim TKH, Veeravalli L, Yuan J, Teo ASM, Chan CX, Poh HM, Chua IML, Liew AA, Lau DPX, Kwang XL, Toh CK, Lim WT, Lim B, Tam WL, Tan EH, Hillmer AM, and Tan DSW
- Subjects
- Adenocarcinoma ethnology, Adenocarcinoma pathology, Asian People genetics, Cell Line, Tumor, Drug Resistance, Neoplasm drug effects, Drug Resistance, Neoplasm genetics, Genetic Predisposition to Disease ethnology, Genetic Predisposition to Disease genetics, Humans, Lung Neoplasms ethnology, Lung Neoplasms pathology, Protein Kinase Inhibitors pharmacology, Adenocarcinoma genetics, ErbB Receptors genetics, Genomics methods, Lung Neoplasms genetics, Mutation, Exome Sequencing methods
- Abstract
EGFR-mutant lung adenocarcinomas (LUAD) display diverse clinical trajectories and are characterized by rapid but short-lived responses to EGFR tyrosine kinase inhibitors (TKIs). Through sequencing of 79 spatially distinct regions from 16 early stage tumors, we show that despite low mutation burdens, EGFR-mutant Asian LUADs unexpectedly exhibit a complex genomic landscape with frequent and early whole-genome doubling, aneuploidy, and high clonal diversity. Multiple truncal alterations, including TP53 mutations and loss of CDKN2A and RB1, converge on cell cycle dysregulation, with late sector-specific high-amplitude amplifications and deletions that potentially beget drug resistant clones. We highlight the association between genomic architecture and clinical phenotypes, such as co-occurring truncal drivers and primary TKI resistance. Through comparative analysis with published smoking-related LUAD, we postulate that the high intra-tumor heterogeneity observed in Asian EGFR-mutant LUAD may be contributed by an early dominant driver, genomic instability, and low background mutation rates.
- Published
- 2018
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20. Systems consequences of amplicon formation in human breast cancer.
- Author
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Inaki K, Menghi F, Woo XY, Wagner JP, Jacques PÉ, Lee YF, Shreckengast PT, Soon WW, Malhotra A, Teo AS, Hillmer AM, Khng AJ, Ruan X, Ong SH, Bertrand D, Nagarajan N, Karuturi RK, Miranda AH, and Liu ET
- Subjects
- Base Sequence, Cell Line, Tumor, Female, Gene Amplification, Gene Duplication, Gene Expression Profiling, Gene Expression Regulation, Neoplastic, Humans, MCF-7 Cells, Molecular Sequence Data, Sequence Analysis, DNA, BRCA1 Protein genetics, Breast Neoplasms genetics, Chromosome Aberrations, Chromosomes, Human, Pair 17 genetics, Receptor, ErbB-2 genetics
- Abstract
Chromosomal structural variations play an important role in determining the transcriptional landscape of human breast cancers. To assess the nature of these structural variations, we analyzed eight breast tumor samples with a focus on regions of gene amplification using mate-pair sequencing of long-insert genomic DNA with matched transcriptome profiling. We found that tandem duplications appear to be early events in tumor evolution, especially in the genesis of amplicons. In a detailed reconstruction of events on chromosome 17, we found large unpaired inversions and deletions connect a tandemly duplicated ERBB2 with neighboring 17q21.3 amplicons while simultaneously deleting the intervening BRCA1 tumor suppressor locus. This series of events appeared to be unusually common when examined in larger genomic data sets of breast cancers albeit using approaches with lesser resolution. Using siRNAs in breast cancer cell lines, we showed that the 17q21.3 amplicon harbored a significant number of weak oncogenes that appeared consistently coamplified in primary tumors. Down-regulation of BRCA1 expression augmented the cell proliferation in ERBB2-transfected human normal mammary epithelial cells. Coamplification of other functionally tested oncogenic elements in other breast tumors examined, such as RIPK2 and MYC on chromosome 8, also parallel these findings. Our analyses suggest that structural variations efficiently orchestrate the gain and loss of cancer gene cassettes that engage many oncogenic pathways simultaneously and that such oncogenic cassettes are favored during the evolution of a cancer., (© 2014 Inaki et al.; Published by Cold Spring Harbor Laboratory Press.)
- Published
- 2014
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21. Targeted inactivation and identification of targets of the Gli2a transcription factor in the zebrafish.
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Wang X, Zhao Z, Muller J, Iyu A, Khng AJ, Guccione E, Ruan Y, and Ingham PW
- Abstract
Hedgehog (Hh) signaling is mediated by the Gli transcription factors and, in the zebrafish, plays an important role in patterning both the neural tube and myotome. Using a null allele of the gli2a gene induced by targeted mutagenesis, we show that Gli2a is completely dispensable in the fish but acts redundantly with Gli1 to regulate expression of known Hh targets, such as ptch2, prdm1a and eng2a, in the myotome and neural tube. To identify novel targets of Hh signaling, we performed chromatin immunoprecipitation sequencing (ChIP-seq) of whole embryo extracts. Samples were significantly enriched for 192 genomic regions, some of which are associated with four known Hh target genes, ptch1, ptch2, gli1 and olig2. Sequence analysis of these regions reveals a high level of conservation of Gli-binding sites from fish to mammals in some, but not all, cases. Expression analysis of other transcription units that are closely associated with peaks identified several putative targets not previously implicated as Hh targets, including myl10, hnmt, lrp4, efemp2, fras1, quo, and lamc1. Each of these genes shows loss of, or reduced expression in, embryos homozygous for an antimorphic allele of gli2a, you-too (yot), consistent with their being direct targets of Gli2a.
- Published
- 2013
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