ALLELIC IMBALANCE AND INSTABILITY OF MICROSATELLITE LOCI ON CHROMOSOME 1P IN HUMAN NON-SMALL-CELL LUNG-CANCER

The mapping of allelic loss on the short arm of chromosome I has been performed in non-small-cell lung cancer. We used a set of II microsate llite loci spanning Ip to examine the frequency of allelic imbalance i n a panel of 58 tumours. Fifty-one of 58 (87.9%) cases have shown soma tic allelic loss at one or more loci tested. The two shortest regions of the overlap (SRO) of the deletions have been identified: SRO I at 1 p13.1 and SRO 2 at 1p32-pter. Allelic losses at these regions have bee n compared among adenocarcinoma and squamous cell carcinoma and no dif ference has been found. In contrast to SRO I, deletions at SRO 2 signi ficantly correlated with advanced stage of the disease as well as post -operative metastasizing and relapse. These data may suggest that SRO 1 and SRO 2 can harbour tumour-supressor genes (TSGs) involved in diff erent stages of NSCLC development. SRO 2 is still quite large and its refined mapping should help attempts to clone and identify the putativ e TSG(s), Microsatellite instability (replication errors) affecting on ly 6 (10.3%) of 58 tumour samples is an infrequent genetic alteration at the loci tested.