In histology, it is very difficult to distinguish it from the other "-blast" cells (lymphoblast, myeloblast, monoblast, and megakaryoblast).

Proerythroblasts arise from the CFU-e (colony-forming unit erythroid) cells, and give rise to basophilic erythroblasts.

In vivo, starting with the proerythroblast stage, erythroid cells undergo several more cell divisions while at the same time upregulating survival genes such as Bcl-xL, acquiring and storing large amounts of iron, ramping up the synthesis of hemoglobin and other erythroid genes (in large part a GATA-1 dependent process that is augmented by the EpoR signaling) and decreasing in cell size, eventually removing their nuclei and being released into the bloodstream as a reticulocyte.

The distinguished feature of pro erythroblast to its corresponding myeloblast in granulocytic series is that it carries more basophilic peripheral cytoplasm.

[citation needed] However, other sources[1] consider "proerythroblast" to be a parent term, divided into the following two categories: