Neoplasia and the erythron.

Neoplasms may affect the erythroid system in a variety of ways. By far the most common abnormality associated with neoplastic disorders is anemia. It is important to recognize that there are multiple causes of anemia associated with neoplasms, because therapy of the anemia varies according to the causative mechanism. Less commonly, the paraneoplastic syndrome of erythrocytosis may occur in some patients with neoplasia. More subtle abnormalities of the erythrocytes associated with malignant disease include modification of the RBC membrane, changes in erythrocyte enzymes, and abnormalities in hemoglobin production. Clinical awareness of the multiple effects of neoplasms on the erythron will lead to better patient management and may also improve our understanding of erythropoiesis.