Scientific Areas of Expertise: Cancer Therapeutics, Gastrointestinal Malignancies, Molecular Diagnostics
For pioneering efforts to provide the first definitive examples of circulating tumor DNA being successfully used as a cancer biomarker for screening, monitoring, and detection of occult disease, and for the discovery of the therapeutic link between immunotherapy and cancer genetics in patients with mismatch repair deficient tumors.
A cancer research luminary, Dr. Diaz has helped refine precision oncology by linking tumor genetics to detection, monitoring, and immunotherapy across multiple solid tumors. Central to his impact is the development and clinical validation of circulating tumor DNA (ctDNA) as a practical biomarker. Through prospective studies spanning pancreatic, ovarian, colorectal, bladder, gastroesophageal, breast, melanoma, hepatocellular, and head and neck cancers, his team showed that ctDNA can be detected with high sensitivity and that quantitative ctDNA dynamics track minimal residual disease, emerging resistance, and treatment response. These groundbreaking findings established ctDNA as a generalizable, tumor-agnostic readout of disease burden and enabled genotype discovery from blood, noninvasive longitudinal monitoring, and risk-adapted care pathways. By pairing analytical assays with clinical endpoints, Dr. Díaz’s program moved liquid biopsy from concept to clinic and provided the groundwork to integrate ctDNA into therapeutic trials and routine oncology practice
In parallel, Dr. Diaz further advanced molecular early detection with his development of a molecular Pap smear for ovarian and endometrial cancers that demonstrated a minimally invasive path to gynecologic cancer detections. He discovered that routinely collected DNA from a Pap smear could be used to reliably detect somatic mutations present in rare endometrial or ovarian cancer tumor cells that accumulate in the cervix. Additionally, his work connected mismatch-repair deficiency and microsatellite instability with PD-1 blockade across different tumor types, which reframed immunotherapy selection around genomic phenotype rather than histology and led to the first FDA tissue-agnostic approval of pembrolizumab. The contributions of Dr. Diaz have reshaped clinical decision-making and accelerated the adoption of genomically informed care. He continues to expand these platforms to refine blood-based detection, integrate multi-omic assays with immunotherapy, and drive precision-medicine trials that translate molecular insight into durable benefit for patients.
Selected Awards and Honors
2021 Elected Member, American Association of Physicians, Philadelphia, Pennsylvania
2021-2024 Board of Directors, American Association for Cancer Research, Philadelphia, Pennsylvania
2021 Member, National Cancer Advisory Board (U. S. Presidential appointment)
2020 AACR-Waun Ki Hong Award for Outstanding Achievement in Translational and Clinical Cancer Research, Association for American Cancer Research, Philadelphia, Pennsylvania
2018 Elected Member, American Society for Clinical Investigation, Ann Arbor, Michigan
2017 AACR Team Science Award, American Association for Cancer Research, Philadelphia, Pennsylvania
2014 AACR Team Science Award, American Association for Cancer Research, Philadelphia, Pennsylvania
2013 AACR Team Science Award, American Association for Cancer Research Philadelphia, Pennsylvania
[Institutional affiliations listed for Fellows reflect those held at the time of their induction into the AACR Academy.]