Advances in Brief Search for Mutations and Examination of Allei ic Expression Imbalance of the p73 Gene at Ip36.33 in Human Lung Cancers1

We examined 61 lung cancer cases to determine whether alterations of p73, a novel monoallelically expressed p53-like molecule, may be involved in the pathogenesis of lung cancer. Allelic loss at the/;73 locus at Ip36.33 was observed in 42% (11 of 26 informative cases), and squamous cell carcinoma tended to carry this lesion most frequently. Somatic mutations in the p73 gene itself, however, were not detected, despite our extensive search. We found interindividual difference in the alleile expression of p73 in normal lung, as well as intertissue variance, even within the same individual, but preferential loss of the expressed alÃ-eleappeared to be an unlikely mechanism for p73 inactivation. This study, consequently, sug gests the presence of an as yet unidentified tumor suppressor gene or genes within the subtelomeric region of Ip, warranting further studies aimed at its isolation.