Chromosome-11q13 gene amplifications in head and neck squamous-cell carcinomas - relation with lymph-node invasion.

Gene amplifications occurring in the q13 band of chromosome 11 are frequently observed in head and neck squamous cell carcinomas. In order to determine the relative frequency of amplification in 5 distinct 11q13 loci and their relation with clinical data, tumor DNAs from 31 patients - including 26 who had undergone neck dissection (lymph node histology available) - were evaluated by Southern blot. Specific probes were used for the D11S833E, FGF3, CYCD1, D11S97 and GST-pi loci. The most frequently amplified loci were CYCD1 and FGF3 (each locus affected in 17 out of 19 patients with 11q13 amplifications). The range of amplification was from 2x to 9x. Seven (54%) of 13 NO patients had 11q13 amplifications versus 12 (67%) of 18 N1-N3 patients (ns). Among 26 patients for whom lymph node histology was available, 3 (33%) of 9 N- patients had 11q13 amplifications compared to 13 (76%) of 17 N+ patients (p=0.03, G2 test). Fourteen (56%) out of 25 patients staged T>N (for example T4 N1) had 11q13 amplifications versus 5 (83%) of 6 patients N greater-than-or-equal-to T (for example T2 N3) (ns). Of 21 well-differentiated HNSCC, 12 (57%) had 11q13 amplifications versus 7 (70%) of 10 moderately and poorly-differentiated tumors. Three year survival (Kaplan-Meier) was 72.9% for patients without 11q13 amplifications and 44.9% for patients with 11q13 amplifications (ns). Chromosome 11q13 gene amplifications thus appear as a potential prognostic marker, possibly related to loco-regional spread in head and neck squamous cell carcinomas.