Matthew J. Ellis

Matthew J. Ellis, MB BChir, PhD, FMedSci is Director of the Lester and Sue Smith Breast Center and Professor of Medicine at Baylor College of Medicine, and a pioneer in the genomic characterization and endocrine treatment of luminal (HR-positive) breast cancer. He directed the neoadjuvant window-of-opportunity breast cancer research program at Washington University in St. Louis before moving to Baylor, where he has continued landmark translational work connecting tumor genomics to treatment outcomes. He led the genomic analysis of the TCGA (The Cancer Genome Atlas) breast cancer dataset, published in Nature in 2012, which comprehensively characterized the somatic landscape of breast cancer subtypes and revealed that luminal A tumors share more molecular similarity with ovarian cancer than with basal-like tumors. Prof. Ellis also served as principal investigator for the PALLAS trial, the large randomized adjuvant trial evaluating palbociclib combined with endocrine therapy in HR+/HER2- early breast cancer. Published in the Journal of Clinical Oncology in 2021, PALLAS did not demonstrate improved iDFS with palbociclib, in contrast to MonarchE, prompting important investigations into potential differences in CDK4/6 inhibitor biology, treatment duration, and patient selection. His laboratory's work on the functional genomics of endocrine resistance, CCND1 amplification, and CDK4/6 pathway biology has illuminated why responses to CDK4/6 inhibition differ across the HR+ early breast cancer population.