(a) Genome-wide frequencies of copy-number gains (above 0, green) and losses (below 0, red) detected by MCG Cancer Array-800 in 18 oral squamous-cell carcinoma cell lines. Clones are ordered from chromosomes 1–22, X and Y and within each chromosome on the basis of the UCSC mapping position (http://genome.ucsc.edu/(version May, 2004)). Green asterisks (*), regions with high-level amplification (log 2 ratio >2); red asterisks (*), regions with homozygous deletion (log 2 ratio<−2) detected with either MCG Cancer Array-800 or MCG Whole Genome Array-4500. (b) Representative duplicate array-based comparative genomic hybridisation image (MCG Whole Genome Array-4500) of the HSC-6 cell line. A remarkable decrease in copy-number ratio (log 2 ratio<−2) of RP11-165A20, 80K21 and 66P13 (red arrows) at 10p12 was detected as a clear red signal. (c) Representative copy-number profiles of chromosome 10 in HSC-6 cells. The vertical back bar indicates candidate spots showing patterns of homozygous deletion at 10p12 (log 2 ratio<−2).