Meta-analysis and pooled re-analysis of copy number changes in colorectal cancer detected by comparative genomic hybridization.

BACKGROUND: Comparative genomic hybridization (CGH) provides an insight into chromosomal changes associated with colorectal cancer (CRC) development. However, a problem with many studies is the limited cohort size, making the significance of some findings unclear. MATERIALS AND METHODS: To derive a better insight into the chromosomal changes associated with CRC, we performed a meta-analysis and pooled re-analysis of published metaphase CGH data. RESULTS: In addition to recurrent alterations, gains of 20 13q, 8q and 7p and loss of 18, 17p, 8p and 4p, pooling identified less frequent, but significant changes, including gain of 1q and 3, and losses from 6q, 9p and 21q. CONCLUSION: These additional alterations may be characteristic of some tumors and thus have relevance to CRC biology. Meta-analysis not only has the potential to detect novel changes, present at low frequency in several independent studies, but can provide greater reliability for their detection than single studies alone.