HOMOZYGOUS DELETIONS OF HUMAN-CHROMOSOME 3P IN LUNG-TUMORS

Cytogenetic and loss of heterozygosity (LOH) studies have demonstrated that deletions of chromosome 3p occur at a high frequency in all form s of lung cancer, To clarify the role of 3p in lung tumorigenesis and to more precisely identify targets for positional cloning efforts, we have performed 3p deletion analyses (microsatellite and fluorescence i n situ hybridization) in a series of lung cancer cell lines and uncult ured tumor samples. Importantly, we identified homozygous deletions in four uncultured tumors and one cell line. Homozygous deletions were f ound in three squamous tumors within a region of 3p21 which had previo usly been described only in cell lines, a 1-2-megabase homozygous dele tion in a small cell tumor at 3p12, and a 3p14.2 homozygous deletion i n a non-small cell lung carcinoma cell line, The detection of homozygo us deletions affecting these multiple regions in uncultured tumor cell s substantiates the belief (previously based on deletions found only i n tumor cell lines) that these sites contain important tumor suppresso r genes, Along with previously reported homozygous deletions in a dist al portion of 3p21.3, we now have evidence for four separate regions o f 3p which undergo homozygous deletions in either uncultured lung tumo rs or cell lines.