Refinement of regions with allelic loss on chromosome 18p11.2 and 18q12.2 in esophageal squamous cell carcinoma

Esophageal cancer ranks among the 10 most common cancers worldwide and is a lmost invariably fatal. The detailed genetic repertoire involved in esophag eal carcinogenesis has not been defined. We have shown previously that the esophageal squamous cell carcinoma genome exhibits a frequent loss of heter ozygosity (LOH) in the pericentromeric region of chromosome 18. To construc t a fine deletion map, we screened 76 new samples composed of microdissecte d esophageal squamous cell carcinoma and matched morphologically normal epi thelial cells using closely spaced markers. Maximal LOH frequency (54%) was displayed by D18S542 on 18p11.2. The pattern of LOH in selected patients i ndicated that the short region of overlap extends 3 cM on either side of D1 8S542. On the long arm of chromosome 18, the highest frequency of allelic l oss (42%) was detected by D18S978 on 18q12.2-q21.1. This analysis revealed a short region of overlap of similar to 0.8 cM. These findings further impl icate unreported tumor suppressor genes encoded by 18p11.2 and 18q12.2 in e sophageal squamous cell carcinogenesis and they indicate a refinement of th eir map location.