TUMOR PROGRESSION AND LOSS OF HETEROZYGOSITY AT 5Q AND 18Q IN NONSMALL CELL LUNG-CANCER

We investigated the frequency and clinical significance of loss of het erozygosity (LOH) at the APC, MCC, and DCC tumor suppressor gene loci in 108 cases of resected non-small cell lung cancer (NSCLC). LOH at th e APC/MCC gene cluster at chromosome 5q21 occurred frequently; it affe cted 29% of informative NSCLC cases and correlated with a significantl y worse survival (P < 0.01). Furthermore, in the subtype most frequent ly affected (SCC), LOH at 5q not only correlated with a worse survival but also tumor involvement of the mediastinal and/or hilar nodes. In contrast, LOH at the DCC locus at chromosome 18q was far less frequent , occurring in 14% of NSCLC cases, and it was not associated with adva nced stage or prognosis. These data suggest that LOH at 5q has a role in determining tumor progression and survival in NSCLC, and may prove to be a clinically useful prognostic indicator.