CGH-DETECTED DNA-SEQUENCE COPY NUMBER AMPLIFICATIONS CAN BE CONFIRMEDBY INTERPHASE-FISH - NEW POSSIBILITIES FOR PROGNOSTIC APPROACHES IN ORAL SQUAMOUS-CELL CARCINOMAS

In order to control the data obtained by comparative genomic hybridiza tion (CGH) on DNA sequence copy number amplifications, 20 oral squamou s cell carcinomas (SCC) were subjected to interphase fluorescence in s itu hybridization (I-FISH) examination using specific DNA probes for t he oncogenes ina and erbB-2, and the corresponding centromeric probes of chromosomes 11 and 17. In all cases characterized by distinct peaks of the CGH profile on the critical chromosomal\ segment 11q13, these data could be clearly substantiated by the I-FISH analyses using the i nt2 probe and estimating the signal index, the int2/centromer 11 relat ion, and the fraction of nuclei with high int2 signal numbers. In addi tion, I-FISH detected smaller cell fractions with high signal numbers (and/or signal clusters) in some tumors which were not definitely cons picuous in CGH. In contrast to int2, erbB-2 amplification apparently d oes not play a major role in oral SCCs, as the blurred peaks of CGH pr ofiles on chromosome 17q11.2-q12 corresponded well with the findings o f I-FISH using the erbB-2 probe. Gain of a whole chromosome 17 is appa rently a rather common feature of these tumors. In conclusion, the com bination of interphase FISH with oncogene-specific probes and CGH is r egarded as a valuable means of practical molecular cytogenetic analysi s of oral SCCs which could eventually achieve high practical importanc e in the pathologic analysis of these tumors and in prognosis of their development.