I-FISH control of CGH-detected gain of DNA sequence copy number in oral squamous cell carcinomas (OSCC)

Interphase fluorescence in situ hybridization (I-FISH) was used to control the gain of genomic material in;21 human oral squamous cell carcinomas (OSC C) which had been detected by comparative genomic hybridization (CGH). DNA probes for 3q27, for 5p15.2, and for the protooncogenes c-myc (8q24) and c- abl (9q34), were used for I-FISH examination of the interphase nuclei of pa raffin sections of the tumors. The corresponding alphoid DNA probes for the centromeric regions of the respective chromosomes and a probe on 5q served as controls of aneusomy. Previous examinations with int2 (11q13) and erbB2 (17q11.2-13) were included for comparison. I-FISH analysis detected a gain of 3q27 in 17, of 5p15.2 in 7, of c-myc in 14, of c-abl in 10, and formerl y, of int2 in 12 and of erbB2 in 10 of the examined tumors. There was an ov erall confirmation of the CGH findings by the I-FISH data in 63 % (36 - 83 % depending on the studied chromosomal site), and vice versa of 76 % of the I-FISH results by the CGH data. Based on these results it is recommended t o use a combination of both I-FISH and CGH for the detection of genomic cha nges in human solid rumors as the data obtained by both techniques ideally complete each other: For this reason both techniques have now enriched the spectrum of molecular histopathology.