Figures 7A and B illustrate chromosome metaphase spreads confirming FISH probe specificities for chromosomes 12p and 12q, respectively, whereas Figures 7C and D show representative colorectal tumour FISH analysis. Figure 7C illustrates a tumour sample (study code 1271) in which the K-Ras gene is not amplified (red fluorescence=green fluorescence), whereas Figure 7D illustrates a colorectal tumour (study code 1264) with K-Ras gene amplification (red fluorescence>green fluorescence). Here, KRAS is linked to colorectal neoplasm.