Endothelial progenitor cell (EPC) nomenclature remains ambiguous and there is a general lack of concordance in the stem cell field
with many distinct cell subtypes continually grouped under the term “EPC.” It would be highly advantageous to agree on standards to
confirm an endothelial progenitor phenotype and this should include detailed immunophenotyping, potency assays, and clear separation
from hematopoietic angiogenic cells which are not endothelial progenitors. In this review, we seek to discourage the indiscriminate
use of “EPCs,” and instead propose precise terminology based on defining cellular phenotype and function. Endothelial colony
forming cells and myeloid angiogenic cells are examples of two distinct and well-defined cell types that have been considered EPCs
because they both promote vascular repair, albeit by completely different mechanisms of action. It is acknowledged that scientific
nomenclature should be a dynamic process driven by technological and conceptual advances; ergo the ongoing “EPC” nomenclature
ought not to be permanent and should become more precise in the light of strong scientific evidence. This is especially important as
these cells become recognized for their role in vascular repair in health and disease and, in some cases, progress toward use in cell
therapy.