HOMOZYGOUS DELETION MAPPING AT 9P21 IN BLADDER-CARCINOMA DEFINES A CRITICAL REGION WITHIN 2CM OF IFNA

We have screened 165 cases of primary transitional cell carcinoma of t he bladder for loss of heterozygosity of markers on chromosome 9. High density deletion mapping was then carried out on a panel of 16 tumour s with partial deletions of 9p using 15 microsatellite markers. Seven tumours had hemizygous deletions which included small interstitial los ses and large terminal deletions. Homozygous deletions of one or more markers were identified in the remaining 9 tumours. By comparing the l imits of hemi- and homozygous deletions in these tumours we have defin ed a single common region of 2cM flanked by IFNA and D9S171.