CD98 is expressed on several tissue types and specifically upregulated on fast-cycling cells undergoing clonal expansion. Various solid (e.g., nonsmall cell lung carcinoma) as well as hematological malignancies (e.g., acute myeloid leukemia) overexpress CD98. We have identified a CD98-specific mouse monoclonal antibody that exhibits potent preclinical antitumor activity against established lymphoma tumor xenografts. Additionally, the humanized antibody designated IGN523 demonstrated robust tumor growth inhibition in leukemic cell-line derived xenograft models and was as efficacious as standard of care carboplatin in patient-derived nonsmall lung cancer xenografts. In vitro studies revealed that IGN523 elicited strong ADCC activity, induced lysosomal membrane permeabilization and inhibited essential amino acid transport function, ultimately resulting in caspase-3 and -7-mediated apoptosis of tumor cells. IGN523 is currently being evaluated in a Phase I clinical trial for acute myeloid leukemia (NCT02040506). Furthermore, preclinical data support the therapeutic potential of IGN523 in solid tumors.