[Analysis of rearrangements in the first exon of c-myc oncogene in squamous cell carcinoma of the head and neck].

Activation of c-myc has been implicated in the origin of different human tumors, and can be produced by diverse mechanisms as amplifications or rearrangements. We examined 55 squamous cell carcinomas of the upper aerodigestive tract for rearrangements involving the first exon of c-myc, which plays a regulatory role in the c-myc expressión. Polymerase chain reaction (PCR) amplification of different fragments of c-myc exon 1 was performed using four oligonucleotide primers that correspond to consecutive sequences from the 5' end of the c-myc exon 1, combined with one oligonucleotide that corresponds to the 3' end. Amplified c-myc PCR products appear as single bands of 580, 495, 417 and 333 base pairs on the electrophoretic analysis. Only in one case a rearrangement involving the first exon of c-myc was found. We concluded that gene rearrangement is not a common mechanism of activation of c-myc in squamous cell carcinomas of the head and neck.