Genomic profiles at different stages in the transformation protocol. CGH plots of 4G cells and 4G cells infected with the PIK3CA vector show no copy number changes. Silencing of p53 in 4G cells leads to loss of chr X and minor changes on chromosomes 3 and 5 which do not progress after introduction of the PIK3CA vector. The spike on chromosome 3q in 4G PIK3CA and 4G shp53 PIK3CA cells is caused by four exonic probes in the PIK3CA locus. There were no additional changes after passage in mice.