early T cell progenitor acute lymphoblastic leukemia (MONDO_0100291, a Monarch Disease Ontology entry) is t acute lymphoblastic leukemia in which the blasts have unique immunophenotypic and genetic characteristics suggesting only limited early T-cell differentiation. Also known as: ETP ALL, ETP-ALL, early T acute lymphoblastic leukaemia, early T acute lymphoblastic leukemia, early T-cell precursor acute lymphoblastic leukaemia, early T-cell precursor acute lymphoblastic leukemia, early T-cell precursor lymphoblastic leukaemia, early T-cell precursor lymphoblastic leukemia.