1) Comparative genomic hybridization (CGH) is a technique that allows the detection of losses and gains in DNA copy number across the entire genome without prior knowledge of specific chromosomal abnormalities. Comparative genomic hybridization utilises the hybridization of differentially labelled tumour and reference DNA to generate a map of DNA copy number changes in tumour genomes. Comparative genomic hybridization is an ideal tool for analysing chromosomal imbalances in archived tumour material and for examining possible correlations between these findings and tumour phenotypes.

2) Technique which produces a map of DNA sequence copy number as a function of chromosomal location throughout the entire genetic genome, and allows the detection of genetic deletions, duplications, and amplifications.