Deletion mapping defines three discrete areas of allelic imbalance on chromosome arm 8p in oral and oropharyngeal squamous cell carcinomas.

Deletions on chromosome arm 8p, as defined by allelic imbalance, are a frequent event in many different types of malignant tumors, including those of the head and neck. These regions are thought to harbor tumor suppressor genes. In order to define a high-density deletion map of this chromosomal arm in oral and oropharyngeal squamous cell carcinomas, we have tested for allelic imbalance in 35 such tumors with 22 short tandem-repeat polymorphisms. Overall, 21 (60%) of the 35 tumors showed allelic imbalance at one or more loci on chromosome arm 8p. Interstitial deletions defined three discrete areas of deletion: at 8p23, 8p22, and 8p12-p21. Tumors of TNM stages II-IV showed a significantly higher frequency of allelic imbalance on 8p than did TNM stage I tumors. Our data suggest that there are least three tumor suppressor loci on chromosome arm 8p that may be implicated in oral carcinogenesis. Furthermore, inactivation of such genes may be associated with high-grade tumors.