Methods and compositions are provided for controlling cell distribution within an implantable bioartificial organ by exposing the cells to a treatment that inhibits cell proliferation, promotes cell differentiation, or affects cell attachment to a growth surface within the bioartificial organ. Such treatments include (1) genetically manipulating cells, (2) exposing the cells to a proliferation-inhibiting compound or a differentiation-inducing compound or removing the cells from exposure to a proliferation-stimulating compound or a differentiation-inhibiting compound; exposing the cells to irradiation, and (3) modifying a growth surface of the bioartificial organ with extracellular matrix molecules, molecules affecting cell proliferation or adhesion, or an inert scaffold, or a combination thereof. These treatments may be used in combination. Cells can be transformed with a proliferation-promoting gene such as the oncogene, SV40, linked to a regulatable promoter such as the Mx1 promoter, the promotor is activated in vitro to express the gene to result in cell proliferation, and the promotor is inactivated before or after insertion of the cells in the bioartificial organ to inhibit expression of the gene to reduce or stop cell proliferation in vivo. The promoter can be reactivated in vivo to again express the gene to result in further cell proliferation. The gene may be a proliferation-suppressing gene such as p53 gene or RB gene, or a differentiation-inducing gene such as high mobility group chromosomal protein 14. Inhibiting gene expression in vitro causes cell proliferation, and inducing gene expression reduces or stops cell proliferation in vivo.