Cyclin D2 overexpression confers myeloid progenitors with enhanced and prolonged granulocyte production potential in vitro. Control- and cyclin D2–transduced LSK cells were cultured in serum-free medium with SFM. Following 7 and 14 days of culture, total cell numbers were enumerated, and the frequency of granulocytes was established following May-Grünwald-Giemsa staining of cytospin slides. Data are mean (SD) values from 5 experiments. *P < .05.