Control array-CGH profiles of the renal cancer cell line 769-P. DNA of the non-amplified 769-P cell line reveals gains of chromosomes 1q, 5q, 8q and losses of 1p, 3p, 6, 9p, 11q, 14 (A, red profile). The corresponding array-CGH profiles of amplified DNA of two biological replicates (ten 769-P cells each) show concordant gains of 1q, 8q, losses of 1p, 3p, 9p, 11q, 14 (B, blue and green profile, respectively). In one of the 769-P cell pools there was an additional loss of 15q (B, blue profile). Gains and losses of the X- and Y-chromosomes (blue profile in B) do not reflect true copy number variations. They result from differences between the sex of the reference and the samples DNA (e.g. female sample DNA was hybridized against a male reference DNA thereby resulting in a gain of X and loss of Y chromosome).