Lillian Siu

Dr. Lillian Siu is a senior medical oncologist and Professor of Medicine specializing in new anticancer drug development, phase I clinical trials, and head and neck malignancies. She is currently Director of the Phase I Program and Co-Director of the Bras and Family Drug Development Program at Princess Margaret Cancer Centre in Toronto, Canada, where she has practiced since 1998. She is the 2024 David A. Karnofsky Memorial Award recipient and serves as President of the American Association for Cancer Research (AACR) starting April 2025.

Current Position

• Senior Medical Oncologist and Director of Phase I Program, Princess Margaret Cancer Centre, Toronto, Canada (July 1998 – Present)
• Professor of Medicine, University of Toronto (2009 – Present)
• Co-Director, Bras and Family Drug Development Program, Princess Margaret Cancer Centre
• BMO Chair in Precision Cancer Genomics (2016 – 2026)
• Clinical Lead, Tumor Immunotherapy Program, Princess Margaret Cancer Centre
• Executive Director, Cancer Genomics Program, Princess Margaret Cancer Centre
• Co-Contact PI, Phase I UM1 Grant, United States National Cancer Institute
• Co-Principal Investigator, Ontario-wide Cancer TArgeted Nucleic Acid Evaluation (OCTANE) Study
• President, American Association for Cancer Research (AACR) (April 2025 – Present)
• Co-Editor-in-Chief, Cancer Research Communications (AACR)
• Editorial Board Member, Cell and Cancer Cell

Education

• MD — University of Toronto
• FRCPC — University of Toronto

Professional Experience

• Senior Medical Oncologist and Director of Phase I Program at Princess Margaret Cancer Centre since July 1998, where she leads the Phase I Program, co-directs the Bras and Family Drug
• Development Program, and serves as Clinical Lead for the Tumor Immunotherapy Program.
• Professor of Medicine at the University of Toronto since 2009, where she has received multiple teaching excellence and mentorship awards.
• President-Elect of the American Association for Cancer Research (AACR) (2024–2025), with her AACR Presidency starting April 2025.
• Board of Directors, American Society of Clinical Oncology (ASCO) (2012–2016), and Chair of the ASCO Conquer Cancer Foundation Grants Selection Committee (2019).
• Board of Directors, American Association for Cancer Research (AACR) (2017–2020), where she also served as Chairperson of the AACR Education Committee, Co-Chairperson of the
• Scientific Committee for the 2012 AACR Annual Meeting, and Co-Chairperson for the Clinical Trials Committee (2015–2017).
• Member, Nomination Committee, American Association for Cancer Research (AACR) (2014–2016).
• Co-Principal Investigator of the OCTANE study, an Ontario-wide cancer targeted nucleic acid evaluation initiative.

Research Activity

• New anticancer drug development with a focus on phase I clinical trials and head and neck malignancies.
• Leading genomics initiatives and immuno-oncology trials at Princess Margaret Cancer Centre through the Cancer Genomics Program and Tumor Immunotherapy Program.
• Co-Contact PI of a Phase I UM1 Grant sponsored by the United States National Cancer Institute.
• Integration of drug development, cancer genomics, and tumor immunotherapy to deliver precision cancer medicine.
• Author of nearly 400 peer-reviewed manuscripts.

Memberships / Honors / Awards

• David A. Karnofsky Memorial Award, ASCO (2024)
• President, American Association for Cancer Research (AACR) (April 2025 – Present)
• Fellow, American Society of Clinical Oncology (FASCO)
• Fellow, American Association for Cancer Research (AACR)
• ASCO International Women Who Conquer Cancer Mentorship Award (2020)
• TAT 2020 Honorary Award for Contributions in the Development of Anticancer Drugs
• University of Toronto, Department of Medicine, Michael Hutcheon Mentor Award (2017–2018)
• University of Toronto, Eaton Scholar Researcher of the Year (2016)
• University Health Network, BMO Financial Group Chair in Precision Genomics (2016–2026)
• University of Toronto, Faculty of Medicine, Division of Medical Oncology, Research Award (2015)
• University of Toronto, Wightman-Berris Award for Individual Teaching Excellence (2013–2014)
• University of Toronto, Division of Medical Oncology, Teaching Award (2011)
• National Cancer Institute, Michaele C. Christian Oncology Development Award (2010)
• Cancer Care Ontario, Tier 1 Research Chair in Experimental Therapeutics (2009)
• Princess Margaret Cancer Centre, Medical Oncology Residency Program Teaching Award (2003)
• University of Toronto, Wightman-Berris Award for Teaching Excellence (2003)
• Fellow, Royal College of Physicians and Surgeons of Canada (FRCPC)

Areas of Specialization

• New anticancer drug development and phase I clinical trials
• Head and neck malignancies
• Cancer genomics and precision medicine
• Tumor immunotherapy and immuno-oncology
• Early phase clinical trial design and leadership

Publications

Dr. Lillian L. Siu has nearly 400 peer-reviewed publications with over 52,000 citations on Google Scholar. Her most influential publications include:

Bedard PL, Hansen AR, Ratain MJ, Siu LL. Tumour Heterogeneity in the Clinic. Nature, 2013; 501(7467):355–364.
Stockley TL, Oza AM, Berman HK, Siu LL, Bedard PL, et al. Molecular Profiling of Advanced Solid Tumors and Patient Outcomes with Genotype-Matched Clinical Trials: The Princess Margaret IMPACT/COMPACT Trial. Genome Med, 2016; 8(1):109.
Siu LL, Lawler M, Haussler D, Voest EE, et al. Facilitating a Culture of Responsible and Effective Sharing of Cancer Genome Data. Nat Med, 2016; 22(5):464–471.
Siu LL, Waldron JN, Chen BE, Parelukar WR, et al. Effect of Standard Radiotherapy with Cisplatin vs Accelerated Radiotherapy with Panitumumab in Locoregionally Advanced Squamous Cell Head and Neck Carcinoma: A Randomized Clinical Trial. JAMA Oncol, 2016.
Cescon D, Siu LL. Cancer Clinical Trials: The Rear-View Mirror and the Crystal Ball. Cell, 2017; 168(4):575–578.
Machiels JP, Tao Y, Licitra L, Obara GS, Siu LL, et al. Pembrolizumab plus Concurrent Chemoradiotherapy versus Placebo plus Concurrent Chemoradiotherapy in Patients with Locally Advanced Squamous Cell Carcinoma of the Head and Neck (KEYNOTE-412). The Lancet Oncology, 2024.
Herrera M, Pretelli G, Desai J, Au L, Siu LL, et al. Bispecific Antibodies: Advancing Precision Oncology. Trends in Cancer, 2024.

Her most recent publications include:

2026

Panasci J, Park CL, Tran B, Siu LL, et al. Advances in Cancer Immunotherapy: Adoptive Cell Therapy and Immune Cell Engagers in Solid Tumours. British Journal of Cancer, Apr 2026.
Siu LL. Precision, Partnership, Purpose: Advancing Cancer Science to Save Lives Globally. Cancer Discovery, Apr 2026.
Elimova E, Ajani J, Klempner SJ, Siu LL, et al. Abstract CT223: AACR Adaptive Biomarker-Driven Organ Preservation Trial in GE Adenocarcinomas (AACR-ADOPT-GEA). Cancer Research, Apr 2026.
Sanz Garcia E, Spreafico A, Hosni A, Siu LL, et al. Abstract CT173: Molecular Residual Disease Interception in Locoregionally Advanced Head and Neck Squamous Cell Carcinoma: The MERIDIAN Phase II Trial. Cancer Research, Apr 2026.
Marret G, An J, Abbas-Aghababazadeh F, Siu LL, et al. Abstract LB122: Dynamic Interactions of Spatially Organized Tumor, Stromal and Immune Cellular Niches Predict Outcome to Immune Checkpoint Blockade in Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma. Cancer Research, Apr 2026.
Chan ATC, Lee VHF, Hong RL, Siu LL, et al. Analysis of Plasma Epstein-Barr Virus DNA and Clinical Outcomes to Pembrolizumab or Chemotherapy in Recurrent/Metastatic Nasopharyngeal Cancer in KEYNOTE-122. Cancer Medicine, Feb 2026.
Siu LL, Burtness BA, Harrington K, Machiels JP, et al. JADE: Phase 3 Study of Sequential Dostarlimab Post Chemoradiotherapy in Patients with Locally Advanced Unresected HNSCC. Future Oncology, Jan 2026.
Rose AAN, Maxwell J, Rousselle E, Spreafico A, et al. Binimetinib and Encorafenib for the Treatment of Advanced Solid Tumors with Non-V600E BRAF Mutations: Results from the Phase II BEAVER Trial. Nature Communications, Jan 2026.

2025

Siu LL. Cancer in 2025. Cancer Discovery, Dec 2025.
Sanz-Garcia E, Soleimani S, Bruce J, Siu LL, et al. Investigating Early Kinetics in Plasma ctDNA and Peripheral T-cell Receptor Repertoire to Predict Treatment Outcomes to PD-1 Inhibitors in Head and Neck Squamous Cell Carcinoma. Clinical Cancer Research, Dec 2025.
Siu LL. The Global State of Blood Cancers: An Ongoing Challenge. Blood Cancer Discovery, Nov 2025.
Siu LL, Yap TA, Genta S, Tolcher AW, et al. A First-in-Human Study of ATM Inhibitor Lartesertib as Monotherapy in Patients with Advanced Solid Tumors. Clinical Cancer Research, Aug 2025.
Stefanovic M, Hernando-Calvo A, Brenes J, Spreafico A, et al. Prognostic Factors in Sinonasal Cancers: A Multicenter Pooled Analysis. The Laryngoscope, Aug 2025.
Fuentes-Antrás J, Elliott MJ, Main S, Cescon DW, Siu LL, et al. Personalized ctDNA Monitoring in Metastatic HR+/HER2- Breast Cancer Patients During Endocrine and CDK4/6 Inhibitor Therapy. npj Breast Cancer, Jul 2025.
Alshankati K, Alshibany A, Toma A, Siu LL, et al. The Use of Machine Learning Models to Predict Progression-Free Survival and Overall Survival Outcomes from Waterfall Plots in Randomized Clinical Trials (MAP-OUTCOMES). ESMO Open, Jul 2025.
Machiels JP, Fayette J, Haddad R, Vokes E, Siu LL, et al. LiGeR-HN Phase III Trials of Petosemtamab + Pembrolizumab and Petosemtamab Monotherapy in Recurrent or Metastatic HNSCC. Future Oncology, Jun 2025.
Tao Y, Siu LL, Licitra LF, Machiels JPH, et al. Long-Term Results of the Randomized, Phase 3 KEYNOTE-412 Trial of Pembrolizumab or Placebo plus Concurrent Chemoradiotherapy for Unresected, Locally Advanced Head and Neck Squamous Cell Carcinoma. Journal of Clinical Oncology, Jun 2025.
Elliott MJ, Kim J, Dou A, Cescon DW, Siu LL, et al. Comprehensive Tumor-Agnostic Evaluation of Genomic and Epigenomic-Based Approaches for the Identification of Circulating Tumor DNA in Early-Stage Breast Cancer. ESMO Open, Jun 2025.
Thomas JS, Siu LL, Ingham M, El-Khoueiry AB, et al. Safety and Efficacy of Intratumorally Administered INT230-6 in Adult Patients with Advanced Solid Tumours. EBioMedicine, Oct 2025.
Siu LL, Powles T. Antibody-Drug Conjugates in Combination Therapy: Defining the Next Chapter. Annals of Oncology, Oct 2025.
Saldanha EF, Siu LL. On the Road to ROME: Defining Tissue-Liquid Concordance in Precision Oncology. Clinical Cancer Research, Oct 2025.
Machiels JP, Tao Y, Licitra L, Siu LL, et al. Health-Related Quality of Life Outcomes from KEYNOTE-412: Chemoradiotherapy with or without Pembrolizumab in Participants with Head and Neck Squamous Cell Carcinoma. Frontiers in Oncology, Oct 2025.
Gounder MM, Martin-Romano P, Italiano A, Postel-Vinay S, Siu LL, et al. Phase 1b and Dose-Expansion Study of GSK3326595, a PRMT5 Inhibitor as Monotherapy and in Combination with Pembrolizumab in Patients with Advanced Cancers. Annals of Oncology, Sep 2025.
Wong MK, Boukhaled G, Armstrong E, Coburn B, Siu LL, et al. Microbial Ecosystem Therapeutics 4 (MET4) Elicits Treatment-Specific IgG Responses Associated with Changes in Gut Microbiota in Immune Checkpoint Inhibitor Recipients. Journal for ImmunoTherapy of Cancer, Mar 2025.
McCoon P, Wang Y, Lai Z, Haddad R, Siu LL, et al. Mutational Landscape of Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma and Association with Immune Checkpoint Inhibitor Outcomes. Clinical Cancer Research, Mar 2025.
Ferrari M, Mularoni F, Smussi D, Tribius S, Siu LL, et al. International Consensus on Laryngeal Preservation Strategies in Laryngeal and Hypopharyngeal Cancer. The Lancet Oncology, May 2025.
Siu LL, Pugh TJ. Extrachromosomal DNA — Amping Up Cancer. The New England Medical Review and Journal, Apr 2025.
Marret G, Herrera M, Siu LL, et al. Turning the Kaleidoscope: Innovations Shaping the Future of Clinical Trial Design. Cancer Cell, Mar 2025.
Horgan D, Tanner M, Aggarwal C, Subbiah V, Siu LL, et al. Precision Oncology: A Global Perspective on Implementation and Policy Development. JCO Global Oncology, Apr 2025.
Fayette J, Licitra L, Harrington K, Cohen RB, Siu LL, et al. INTERLINK-1: A Phase III, Randomized, Placebo-Controlled Study of Monalizumab plus Cetuximab in Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma. Clinical Cancer Research, Apr 2025.
Siu LL, Postel-Vinay S, Villanueva Vázquez R, Massard C, et al. AZD8701, an Antisense Oligonucleotide Targeting FOXP3 mRNA, as Monotherapy and in Combination with Durvalumab: A Phase I Trial in Patients with Advanced Solid Tumors. Clinical Cancer Research, Feb 2025.
Naing A, McKean M, Tolcher A, Siu LL, et al. TIGIT Inhibitor M6223 as Monotherapy or in Combination with Bintrafusp Alfa in Patients with Advanced Solid Tumors: A First-in-Human, Phase 1, Dose-Escalation Trial. Journal for ImmunoTherapy of Cancer, Feb 2025.
Elliott MJ, Echelard P, Pipinikas CP, Cescon DW, Siu LL, et al. Longitudinal Evaluation of Circulating Tumor DNA in Patients Undergoing Neoadjuvant Therapy for Early Breast Cancer Using a Tumor-Informed Assay. Nature Communications, Feb 2025.
Elliott MJ, Howarth K, Main S, Cescon DW, Siu LL, et al. Ultrasensitive Detection and Monitoring of Circulating Tumor DNA Using Structural Variants in Early-Stage Breast Cancer. Clinical Cancer Research, Jan 2025.
Lopez J, Powles T, Braiteh F, Camidge DR, Siu LL, et al. Autogene Cevumeran with or without Atezolizumab in Advanced Solid Tumors: A Phase 1 Trial. Nature Medicine, Jan 2025.
Spreafico A, Winquist E, Ho C, Hao D, Siu LL, et al. A Canadian Perspective on Systemic Therapy for Recurrent or Metastatic Nasopharyngeal Carcinoma. Current Oncology, Jan 2025.
Machtay M, Torres-Saavedra PA, Thorstad W, Young MR, Siu LL, et al. Postoperative Radiotherapy ± Cetuximab for Intermediate-Risk Head and Neck Cancer. Journal of Clinical Oncology, Jan 2025.

2024

Machiels JP, Tao Y, Licitra L, Obara GS, Siu LL, et al. Pembrolizumab plus Concurrent Chemoradiotherapy versus Placebo plus Concurrent Chemoradiotherapy in Patients with Locally Advanced Squamous Cell Carcinoma of the Head and Neck (KEYNOTE-412). The Lancet Oncology, Mar 2024.
Stutheit-Zhao EY, Sanz-Garcia E, Liu ZA, Siu LL, et al. Early Changes in Tumor-Naive Cell-Free Methylomes and Fragmentomes Predict Outcomes in Pembrolizumab-Treated Solid Tumors. Cancer Discovery, Feb 2024.
Sanz-Garcia E, Zou J, Avery L, Siu LL, et al. Multimodal Detection of Molecular Residual Disease in High-Risk Locally Advanced Squamous Cell Carcinoma of the Head and Neck. Cell Death and Differentiation, Feb 2024.
Hernando-Calvo A, Nguyen P, Bedard PL, Hanna TP, Siu LL, et al. Impact on Costs and Outcomes of Multi-Gene Panel Testing for Advanced Solid Malignancies: A Cost-Consequence Analysis Using Linked Administrative Data. EClinicalMedicine, Feb 2024.
Hernando-Calvo A, Yang SYC, Vila-Casadesús M, Bedard PL, Siu LL, et al. Combined Transcriptome and Circulating Tumor DNA Longitudinal Biomarker Analysis Associates with Clinical Outcomes in Advanced Solid Tumors Treated with Pembrolizumab. JCO Precision Oncology, Aug 2024.
Usset J, Rosendahl Huber A, Andrianova M, López-Bigas N, Siu LL, et al. Five Latent Factors Underlie Response to Immunotherapy. Nature Genetics, Sep 2024.
Herrera M, Pretelli G, Desai J, Au L, Siu LL, et al. Bispecific Antibodies: Advancing Precision Oncology. Trends in Cancer, Aug 2024.
Genta S, Araujo DV, Hueniken K, Spreafico A, Siu LL, et al. Bespoke ctDNA for Longitudinal Detection of Molecular Residual Disease in High-Risk Melanoma Patients. ESMO Open, Nov 2024.
Luke J, Gelmon K, Siu LL, Tabernero J, et al. Phase 1/2 Study of the Indoleamine 2,3-Dioxygenase 1 Inhibitor Linrodostat Mesylate Combined with Nivolumab or Nivolumab and Ipilimumab in Advanced Solid Tumors or Hematologic Malignancies. Clinical Cancer Research, Dec 2024.
Gulley JL, Sullivan RJ, Friedman CF, Siu LL, et al. 1470 START001: A Phase 1/2 Study of Invikafusp Alfa, a First-in-Class TCR β Chain-Targeted Bispecific Antibody, as Monotherapy in Patients with Antigen-Rich Solid Tumors Resistant to Anti-PD(L)1. Journal for ImmunoTherapy of Cancer, Nov 2024.
Strum S, Andersen MH, Svane IM, Weber JS, Siu LL, et al. State-of-the-Art Advancements on Cancer Vaccines and Biomarkers. ASCO Educational Book, Jun 2024.
Hernando-Calvo A, Han M, Ayodele O, Hansen AR, Siu LL, et al. A Phase II, Open-Label, Randomized Trial of Durvalumab with Olaparib or Cediranib in Patients with Mismatch Repair-Proficient Colorectal or Pancreatic Cancer. Clinical Colorectal Cancer, May 2024.
Oliva Bernal M, Heirali A, Watson GA, Spreafico A, Siu LL, et al. Prospective Manipulation of the Gut Microbiome with MET4 in HPV-Related Locoregionally-Advanced Oropharyngeal Cancer Patients Undergoing Primary Chemoradiation: ROMA2 Study. British Journal of Cancer, May 2024.
Vasconcelos JPS, Chen N, Titmuss E, Loree JM, Siu LL, et al. Transverse Colon Primary Tumor Location as a Biomarker in Metastatic Colorectal Cancer: A Pooled Analysis of CCTG/AGITG CO.17 and CO.20 Randomized Clinical Trials. Clinical Cancer Research, Jan 2024.

All information is sourced from publicly available materials.