Chromosome 13 presents frequent allelic loss in esophageal squamous cell carcinomas (ESCC). However, no ESCC suppressor gene has been identified from this chromosome. To define common deletion regions that possibly contain the ESCC suppressor gene(s), we performed a mapping of allelic loss in 50 esophageal squamous cell carcinomas using a panel of 25 microsatellite markers on chromosome 13q21-qter, which has rarely been studied for allelic loss. Loss of heterozygosity (LOH) with high frequencies (≥50%) was observed at markers D13S1494, D13S1323, D13S248, D13S1315, D13S285, and D13S1295, in which the peak LOH (69.2%) was at locus D13S248. Seven cases presented LOH at three consecutive markers D13S248, D13S1315 and D13S285, 4 of which also displayed LOH at another adjacent marker D13S1295. This overlapping region of deletion covers an interval of 6.36 Mb at 13q33.1-q34, whose deletion has not previously been reported in ESCC. Tumors of grade II showed significantly more frequent LOH at D13S248 than those of grade I. A significantly higher frequency of allelic loss at D13S152 was also found in tumors with lymph node metastasis compared to those without lymph node metastasis. The present study defined a novel region of allelic loss in 13q33-q34. LOH at D13S248 and D13S152 are associated with higher tumor grade and metastasis, respectively.

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