Comparative genomic hybridization and molecular cytogenetic characterization of two prostate cancer xenografts

Conventional cytogenetic analysis of two prostate tumor xenografts, LuCaP 23.1 and RP22090, was unsatisfactory for comprehensive genetic evaluation of the cell lines. Fluorescence in situ hybridization (FISH) for chromosome enumeration and comparative genomic hybridization (CGH) for numerical imbalance detection were performed and resulted in a more complete molecular cytogenetic characterization of these lines. Both xenografts were hypertriploid and had significant numerical imbalances. For example, LuCaP 23.1 had gain of all or part of chromosomes 3, 5, 6, 7, 8, 11, and 12 and the X chromosome and loss of all or part of chromosomes 2, 3 6, 8, 9, 10, 17, and 18. In RP22090, gain of all or part of chromosomes 5, 7, 8, 9, 10, 12, 14, and 15 was seen, whereas loss was seen for all or part of chromosomes 4, 6, 8, 15, 16, 17, 19, 20, and 22. Both xenografts reflect the high frequency of chromosomal changes seen in some late-stage prostate cancers, including many novel changes and some changes such as the loss of 8p and gain of 8q, which have been reported previously in primary and metastatic prostate cancers. Consistent changes in both lines, such as loss of chromosomes 6 and chromosome arm 8p and gain of chromosome 7 and chromosome arm 8q, may represent genetic events specific for prostate cancer development, but imbalances on other chromosomes such as 3, 9, 19, and 20, not frequently reported in prostate cancers, may reflect potentially important changes that should also be examined.