COMPARATIVE GENOMIC IN-SITU HYBRIDIZATION DISCLOSES CHROMOSOMAL COPY NUMBER CHANGES IN A TRANSPLANTED BRAIN-TUMOR LINE OF THE RAT (RATTUS-NORVEGICUS)

We investigated chromosomal copy number changes in ethylnitrosourea-in duced and serially transplanted gliomas of the rat by flow cytometry a nd Comparative Genomic in situ Hybridization (CGH). CGH analysis of a primary and four transplanted tumors revealed several genomic aberrati ons, including whole chromosome and subchromosomal gains and losses. G ains involved rat Chromosomes (RNO) 2, 3, 4, 5, 7, 9, 11, 12, 13, and Y, whereas losses affected RNO5, 13, 20, and Y. The primary tumor exhi bited gain of RNO2q31qter and gain of RNO4. While gain of RNO2 was see n in nearly all investigated passages, gain of RNO4 was apparent in th e primary tumor and in passage 2 and 5 tumors. Chromosomal alterations detected as single events were restricted to the transplanted tumors and included gain of RNO3q11, 3q41qter, 5q36, 7q34qter, 9q37, 11q, and Y, and loss of RNO5, 13, and 20q. Flow cytometry disclosed different aneuploid cell clones in the tumors investigated. The results are disc ussed in analogy to findings in human glial tumors.