High chromosomal instability in brain metastases of colorectal carcinoma

Information on structural chromosomal changes in brain metastases (BM) of colorectal carcinoma (CRC) is very limited. Therapeutic and diagnostic strategies to reduce the risk of BM have potential impact on cancer mortality. By using comparative genomic hybridization, the primary CRC of 11 patients and their corresponding 13 BM were analyzed. BM showed significantly more mean chromosomal aberrations than the primary CRC (13.6 ± 2.1 vs. 7.9 ± 1.9, P = 0.03), significantly more chromosomal gains (7.2 ± 0.9 vs. 3.5 ± 0.9, P = 0.01), and tended to have also more losses (6.1 ± 1.4 vs. 4.0 ± 1.1, P = 0.29). Changes that occurred significantly more often in BM than in primary CRC were gains of 8q, 12p, 12q, and 20p, as well as losses of 5q. BM of CRC show a significantly higher chromosomal instability in comparison to primary tumors. The prevalently altered genomic regions in the metastases of this study are likely to harbor genes that play an important role in the genesis of brain-specific metastasis.