FREQUENT ALLELIC IMBALANCE AND CYTOGENETIC DELETION ON THE SHORT ARM OF CHROMOSOME 1 IN NASOPHARYNGEAL CARCINOMA

Objective: To construct a fine map of the loss of chromosome lpter-p36.11 region in nasopharyngeal carcinoma (NPC) using PCR-LOH technique. Methods:DNA extracted from separated cancerous cells and their mated noncancerous lymphocytes from 47 cases of NPC biopsies were analyzed by means of PCR-LOH to detect 20loci spanning chromosome lpter-p36.11 region in NPC.Results: In 47 NPC cases, 37 (82.2%) cases showed at least one loci LOH. The highest frequency of less of heterozygosity (LOH) at all 20 loci was found at loci DIS234(50. 0%) on lp36.13 and loci DIS2644 (37.5%) on lp36.22.There was a statistically significant difference betweenDIS234 LOH frequency (60%, 9/15) in early stage and that (50. 0%, 8/16) in advanced stage (P＞0.05). Of all 20 STSs (sequence tqgged-site, STS), DIS243 (37.5%) and DIS199(30.2%) showed the highest frequency of MI (microsatellite instability) on lp36.33 and lp36.21, respectively. In addition,several cases showed a contiguous stretch of allelic loss in a different level. Conclusion: Two minimal deletion regions (MDR) on the short arm of chromosome 1 were seated at lp36.13 (DIS234, 2.0 cm) and lp36.22 (DIS436-DIS2644, 6.3cm) respectively, indicating that one or more candidate tumor suppressor gene (TSG) in the two regions may be involved in NPC pathogenesis in an early clinical stage.