He is focused on the care and research of patients with myeloid malignancies, particularly acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). He also participated in the K12 Calabresi Immuno-Oncology Training Program and currently participates as an investigator in several clinical trials aimed at improving the outcomes of patients with AML and MDS.

Dr. Shallis also maintains research interest in epidemiological, outcomes and effectiveness research as it pertains to the hematologic malignancies with a goal of identifying barriers to effective care and ultimately strategies to improve the outcomes of patients with these malignant diseases. Dr. Shallis conducts research with the Cancer Outcomes, Public Policy and Effectiveness Research (COPPER) Center at Yale University.

Dr. Shallis has presented his research at multiple regional, national and international meetings and is a member of the National Comprehensive Cancer Network (NCCN) clinical guidelines for MDS panel. He is an author on more than 50 peer-reviewed publications and book chapters, most of which as first author and has served as an ad hoc reviewer for many journals including Leukemia, Blood Advances, Leukemia Research, Acta Haematologica, Hematology, Therapeutic Advances in Hematology, Expert Review of Hematology, BMC Hematology, eJHaem, Future Oncology and Expert Review of Anticancer Therapy among others.