The CD44-blocking antibody RO5429083 was tested in a phase I, dose-escalation clinical study in metastatic or locally advanced, CD44-positive malignant solid tumors (NCT01358903) as well as in a phase I clinical study, alone or in combination with cytarabine, for acute myelogenous leukemia (NCT01641250). Here, CD44 is linked to acute myeloid leukemia.