Comparative study of renal cell carcinoma by CGH, multicolor-FISH and conventional cytogenic banding analysis

Using different cytogenetic techniques in combination is crucial to studying the high complexity of genetic rearrangements in tumor cells. The 8 clear cell (cc) and 5 papillary (p) renal cell carcinomas (RCC) were analyzed using multicolor fluorescence in situ hybridization (multicolor-FISH), conventional Giemsa banding (G-banding) and comparative genomic hybridization (CGH) analysis. CGH analysis was carried out with DNA from frozen tissue sections and short-term cultures of primary tumors. Using CGH analysis, both tissue sections and cell cultures of ccRCC showed the typical chromosomal changes such as the loss of 3p, 4q, 6q, 8p, 9q, 14 and a gain of 5q and 7. Most imbalances detected by CGH in cell culture could be deciphered by multicolor-FISH and G-banding analysis as unbalanced trans-locations t(3;6)(p11.1;p11.1), t(8;14)(p11.1;q11.1), t(3;5) (p14;q21-22), t(1;15)(p11;q11.1), t(3;15)(p11;q11.1)t(8;17) (p11.1;q11.1), t(8;17)(q22;p11.1). Only one balanced trans-location t(9;18)(q34;q11.1) was shown in ccRCC. CGH of papillary RCC displayed mostly gains of whole chromosomes 7, 12, 16 and 17 and a loss of chromosome Y. There was 1 papillary RCC that displayed a partial gain of chromosome 7, showing an unbalanced translocation t(7;11)(q11.1;q25). The balanced translocations t(2;9)(q11.1;q34) and t(7;15) (q22~31;q21-22) were registered in pRCC. The combined analysis of RCC by different methods allowed a more accurate characterization of the complex karyotypes of tumor tissue, and offered a comprehensive description of given tumors.