We point to the need for comprehensive characterization of mechanisms underpinning both the acquisition of chromosomal abnormalities and selection pressures, which allow mutations to persist in hPSC cultures.
Thus, our data seem to indicate that the acquisition of genetic abnormalities is not required for the conditional immortalization of human B cells in this system.
However, the precise mechanisms of acquisition of these abnormalities have remained unclear.
The progressive acquisition of genetic abnormalities was demonstrated by only one of eight ependymomas for which successive biopsies were available.
It has been reported that single-cell dissociation using trypsin can accelerate the acquisition of chromosomal abnormalities (Chan et al., 2008).
It may be that the benign stem cells in breast tissue are transformed into malignant stem cells through the acquisition of genetic abnormalities.
Although iPS cells show a normal karyotype after the reprogramming process, it has been reported that continuous passaging of these cells is associated with the acquisition of chromosomal abnormalities (karyotype 46,XY,t(17 20) (p13 p11.2)) starting approximately at passage 13.
We and others have demonstrated multiple alterations in chromatin structure arising as a consequence of EtOH exposure, but linking these epigenetic changes to alterations in the developmental program, and ultimately to the acquisition of congenital abnormalities, has yet to be achieved [ 2, 3].
Now many of techniques are used in diagnosing the biological and clinical differences of leukemic cells, including the acquisition of new chromosomal abnormalities, gene mutations, and reduced responsiveness to chemotherapeutic agents [10] [13].
Similarly, it has been suggested that defects of recombinational/repair pathways may facilitate acquisition of additional cytogenetic abnormalities in CML [ 9, 10].
