Chromosome instability in stem cells

Stem cells (SCs) are able to differentiate into many different cell types of the body during early life and growth. They are unspecialized cells capable of self-renewal and, when chal-lenged, they can be induced to differentiate into specific and mature cell types. SCs can be classified into two different types: somatic stem cells (SSCs) and embryonic stem cells (ESCs). One major problem concerning in vitro SC culture is the difficulty to maintain their genetic and karyotype integrity during long-term culture. This chapter describes the different types of abnormalities accumulated by ESCs, derived from different species, and SSCs, of different somatic origin, during long-term culture in vitro. It outlines the main processes that are implicated in the onset of chromosome abnormalities in cells during culture. Among these processes, only one has been so far described in SCs.