RESUMO
Somatic stem cells possess unique properties of self-renewal and plasticity which make them promising candidates for use in tissue engineering and regenerative medicine, in addition to serving as efficient delivery vehicles in site-specific therapy. In the case of therapeutic application, it is essential to isolate and culture stem cells in vitro, to obtain them in sufficient quantities. Although long-term cultivation provides an adequate number of cells, it has been shown that this approach is associated with increased risk of transformation of cultured cells, which presents a significant biological hazard. This article reviews information about biological features and cellular events which occur during long-term cultivation of somatic stem cells, with respect to their safe utilization in potential clinical practice.