We investigated loss of heterozygosity (LOH) at the distal portion of the p53 gene on the short arm of chromosome 17 in lung cancers in order to search for new tumor suppressor genes. The roles of the putative genes were also studied in terms of pathological features. One hundred and forty-five resected non-small cell lung cancers were examined for LOH using 11 markers mapped on, and distal to the p53 locus, and deletion maps were constructed. Four commonly deleted regions were found: one from TP53 to ENO3, where the p53 gene resides, and three others from ENO3 to D17S1566, D17S379 to D17S1574 and distal to ABR, with LOH frequencies almost the same as, or higher than, at the TP53 locus. Examination of the relationship between LOH of the latter three regions and histopathological parameters of adenocarcinomas (genetically negative for p53 mutation) revealed allelic losses on D17S379 to be associated with advanced lesions, while D17S513 was more frequently deleted in poorly differentiated tumors. These results indicate that new tumor suppressor gene(s) may reside on these three distinctly deleted regions on chromosome 17p13.3 distal to the p53 gene in lung cancer, with possible roles in progression and differentiation of adenocarcinomas.