LOSS OF HETEROZYGOSITY ON CHROMOSOME 17P13 (P53) AND 13Q14 (RB1) IN SQUAMOUS-CELL CARCINOMA OF HEAD AND NECK

Loss of chromosome sequences at 13q14 (Rbl) and 17p13 (p53) associated with squamous cell carcinoma of head and neck (SCCHN) was evaluated i n 12 recurrent tumors and 51 primary tumors from 63 patients. The inci dence of LOH at 17p13 was 19 of 50 (38%) tumors, and at 13q14 was 21 o f 57 (37%). LOH affecting Rbl and/or p53 was observed in 30 of 63 (48% ) SCCHN. Coincident LOH at Rbl and p53 was detected in 10 of 46 (22%) tumors. There were nine cases in which primary and metastatic tumors w ere obtained from the same patient. Of these, seven were informative a nd five of these (71%) manifested LOH at p53 in both primary and metas tatic sites. Examination of Rbl in these same tumors showed LOH in six of the nine metastases, and of these six, only three revealed LOH in the primary tumor. LOH at p53 or Rbl alone showed no correlation with clinical outcome. However, tumors that manifested LOH at both loci wer e associated with poorer patient outcome and poorer histological diffe rentiation.