Assoc Prof Yap Yoon Sim

MBBS, FRACP, PhD

Senior Consultant

National Cancer Centre Singapore National Cancer Centre Singapore

Specialty: Medical Oncology

Conditions Treated By This Doctor

Clinical Interests

Breast

Clinical Appointments

Academic Appointments

Associate Professor

About

Dr. Yap is Senior Consultant in the Division of Medical Oncology at the National Cancer Centre Singapore, and Professor at Duke-NUS Medical School. A recipient of the Singapore National Medical Research Council (NMRC) Clinician Scientist Award (CSA), her research focuses primarily on clinical and translational research in breast cancer, including liquid biopsies and predictive biomarkers, development of novel therapeutic strategies, and epidemiologic studies on treatment outcomes in breast cancer. She is the principal investigator of several phase 1 to 3 clinical trials for various compounds, including novel endocrine agents, small molecule inhibitors, radioligand therapy and immunotherapy, in addition to investigator-initiated studies.

Education and Training

  • PhD, University of Adelaide, Australia, in Medicine
  • FRACP, Royal Australasian College of Physicians, in Medical Oncology
  • MBBS, University of Adelaide, Australia, in Medicine and Surgery

Professional Appointments and Committee Memberships

  • 2010-now Senior Consultant in Medical Oncology, NCC Singapore 
  • 2010-now SingHealth Joint Breast Cancer Registry (JBCR) Steering Committee Member 
  • 2014-now Journal of Breast Cancer Editorial Board 
  • 2016-now Asian Breast Cancer Cooperative Group (ABCCG) Steering Committee Member 
  • 2019-2023 Faculty, European Society of Medical Oncology (ESMO), Breast Cancer Track 
  • 2020-2025 Associate Professor, Duke-NUS Medical School 
  • 2021-now Breast Cancer Research and Treatment Editorial Board 
  • 2022-now Therapeutic Advances in Medical Oncology Editorial Board 
  • 2023-now PI, Breast Cancer Translational Research Laboratory, NCCS 
  • 2023-now Breast Tumor Group Co-Lead, Singapore Translational Cancer Consortium (STCC) 
  • 2025-now Professor, Duke-NUS Medical School

Awards

  • National Medical Research Council (NMRC) Clinician Scientist Award (CSA), 2024 
  • Elder Prize, 1992 for overall academic performance (University of Adelaide) 
  • Golden Key National Honour Society, 1998 for overall scholastic performance (University of Adelaide) 
  • Best Trainee Oral Presentation award at Medical Oncology Group of Australia Conference, 2004 
  • Medical Oncology Group of Australia/Baxter Trainee Educational Achievement Award, 2005 
  • National Medical Research Council (NMRC) Clinician Scientist Award (CSA), 2019

Research Interests

  • Clinical research in breast cancer, including early phase and phase III trials using novel therapeutic regimens.
  • Translational research in breast cancer, including prognostic, predictive biomarkers
  • Observational studies in breast cancer

Research Trials

Publications

  • Zhu G, Rahman CR, Getty V, Odinokov D, Baruah P, Carrié H, Lim AJ, Guo YA, Poh ZW, Sim NL, Abdelmoneim A, Cai Y, Lakshmanan LN, Ho D, Thangaraju S, Poon P, Lau YT, Gan A, Ng S, Koo SL, Chong DQ, Tay B, Tan TJ, Yap YS, Chok AY, Ng MCH, Tan P, Tan D, Wong L, Wong PM, Tan IB, Skanderup AJ. A deep-learning model for quantifying circulating tumour DNA from the density distribu-tion of DNA-fragment lengths. Nat Biomed Eng. 2025 Mar;9(3):307-319. 
  • Wan X, Yap J, Chen J, Li Y, Faruk R, Tan NCB, Ma Y, Lim Y, Jubri KB, Hu J, Yuan J, Zhang G, Li Q, Yap YS, Lam P, Wang M, Fu NY, Hu J. Oncogenic non-V600 mutations evade the regulatory ma-chinery of RAF including the Cdc37/Hsp90 chaperone and the 14-3-3 scaffold. Theranostics. 2025 Jan 6;15(5):2035-2051. 
  • Kim J, Kim J, Seo KH, Lee KH, Park YH, Lin CH, Lu YS, Ueno T, Yap YS, Wong FY, Tan VKM, Lim GH, Tan SM, Yeo W, Liu Q, Leung R, Naito Y, Li H, Lee HB, Han W, Im SA; Asian Breast Cancer Co-operative Group. Survival outcomes of young-age female patients with early breast cancer: an interna-tional multicenter cohort study. ESMO Open. 2024 Nov;9(11):103732. doi: 10.1016/j.esmoop.2024.103732. 
  • André F, Solovieff N, Su F, Bardia A, Neven P, Yap YS, Tripathy D, Lu YS, Slamon D, Chia S, Joshi M, Chakravartty A, Lteif A, Taran T, Arteaga CL. Acquired gene alterations in patients treated with ri-bociclib plus endocrine therapy or endocrine therapy alone using baseline and end-of-treatment circu-lating tumor DNA samples in the MONALEESA-2, -3, and -7 trials. Ann Oncol. 2025 Jan;36(1):54-64. doi: 10.1016/j.annonc.2024.09.010. 
  • Noguchi E, Yamanaka T, Mukai H, Yamamoto N, Chung CF, Lu YS, Chang DY, Sohn J, Kim GM, Lee KH, Lee SC, Iwasa T, Iwata H, Watanabe K, Jung KH, Tanabe Y, Kang SY, Yasojima H, Aogi K, To-kunaga E, Sim SH, Yap YS, Matsumoto K, Tseng LM, Umeyama Y, Sudo K, Kojima Y, Hata T, Ku-chiba A, Shibata T, Nakamura K, Fujiwara Y, Tamura K, Yonemori K. A phase 3 study (PATHWAY) of palbociclib plus tamoxifen in patients with HR-positive/HER2-negative advanced breast cancer. NPJ Breast Cancer. 2024 Aug 22;10(1):76. doi: 10.1038/s41523-024-00684-w. 
  • Tan RYC, Ong WS, Lee KH, Park S, Iqbal J, Park YH, Lee JE, Yu JH, Lin CH, Lu YS, Ono M, Ueno T, Naito Y, Onishi T, Lim GH, Tan SM, Lee HB, Koh J, Han W, Im SA, Tan VKM, Phyu N, Wong FY, Tan PH, Yap YS. Outcomes in Nonmetastatic Hormone Receptor-Positive HER2-Negative Pure Mucinous Breast Cancer: A Multicenter Cohort Study. J Natl Compr Canc Netw. 2024 May 14;22(2 D):e237121. doi: 10.6004/jnccn.2023.7121. 
  • Lu YS, Bin Mohd Mahidin EI, Azim H, Eralp Y, Yap YS, Im SA, Rihani J, Gokmen E, El Bastawisy A, Karadurmus N, Lim YN, Lim CS, Duc LT, Chung WP, Babu KG, Penkov K, Bowles J, Alfaro TD, Wu J, Gao M, Slimane K, El Saghir NS. Final results of RIGHT Choice: Ribociclib plus endocrine therapy vs combination chemotherapy in premenopausal women with clinically aggressive HR+/HER2- advanced breast cancer. J Clin Oncol. 2024 Aug 10;42(23):2812-2821. doi: 10.1200/JCO.24.00144. Epub 2024 May 21. 
  • Prat A, Solovieff N, Andre F, O'Shaughnessy J, Cameron DA, Janni W, Sonke GS, Yap YS, Yardley DA, Partridge AH, Thuerigen A, Zarate JP, Lteif A, Su F, Carey LA. Intrinsic subtype and overall sur-vival of patients with advanced HR+/HER2- breast cancer treated with ribociclib and ET: correlative analysis of MONALEESA-2, -3, -7. Clin Cancer Res. 2024 Feb 16;30(4):793-802. doi: 10.1158/1078-0432.CCR-23-0561. 
  • Loh JW, Lim AH, Chan JY, Yap YS. Classification of HER2-negative breast cancers by ERBB2 copy number alteration status reveals molecular differences associated with chromosome 17 gene aberra-tions. Ther Adv Med Oncol. 2023 Oct 31;15:17588359231206259. doi: 10.1177/17588359231206259. eCollection 2023. 
  • Ma J, Chan JJ, Toh CH, Yap YS. Emerging systemic therapy options beyond CDK4/6 inhibitors for hormone receptor-positive HER2-negative advanced breast cancer. NPJ Breast Cancer. 2023 Sep 8;9(1):74. 
  • Chiu J, Su F, Joshi M, Masuda N, Ishikawa T, Aruga T, Zarate JP, Babbar N, Balbin OA, Yap YS. Po-tential value of ctDNA monitoring in metastatic HR + /HER2 - breast cancer: longitudinal ctDNA analysis in the phase Ib MONALEESASIA trial. BMC Med. 2023 Aug 15;21(1):306. 
  • Yap YS. Outcomes in breast cancer-does ethnicity matter? ESMO Open. 2023 Jun;8(3):101564. doi: 10.1016/j.esmoop.2023.101564. Epub 2023 Jun 7. 
  • Yap YS, Hu J. Exploiting metabolic vulnerabilities in breast cancers with NF1 loss. Cell Rep Med. 2023 Apr 18;4(4):101010. doi: 10.1016/j.xcrm.2023.101010. 
  • HER2 expression, copy number variation and survival outcomes in HER2-low nonmetastatic breast cancer: an international multicentre cohort study and TCGA-METABRIC Analysis. Tan RS, Ong WS, Lee KH, Lim AH, Park S, Park YH, Lin CH, Lu YS, Ono M, Ueno T, Naito Y, Onishi T, Lim GH, Tan SM, Lee HB, Ryu HS, Han W, Tan VKM, Wong FY, Im SA, Tan PH, Chan JY, Yap YS. BMC Medicine 2022; 20: 105 
  • Overall Survival with Ribociclib plus Letrozole in Advanced Breast Cancer. Hortobagyi GN, Stemmer SM, Burris HA, Yap YS, Sonke GS, Hart L, Campone M, Petrakova K, Winer EP, Janni W, Conte P, Cameron DA, André F, Arteaga CL, Zarate JP, Chakravartty A, Taran T, Le Gac F, Serra P, O'Shaughnessy J.N Engl J Med. 2022 Mar 10;386(10):942-950.