Recessive oncogenes in lung cancer.

The observation that carcinogen exposure is strongly associated with the probability of developing pulmonary neoplasms has suggested for many years that acquired somatic mutations play a key role in the genesis of these environmentally induced cancers. With the advent of new techniques in cytogenetics and in the molecular analysis of DNA extracted from lung tumors, it has now become possible to test this hypothesis and to search for candidate genes that may be targeted by the chronic exposure of these environmental insults. Early work in this field, studying lung tumors of different histologic types, appears to implicate several distinct chromosomal loci (at chromosomes 3p, 13q, 17p, and others), suggesting that sequential genetic events occur during the initiation and progression pathways to pulmonary tumorigenesis. Identifying the candidate gene products and understanding the chronology and stringency of mutational events at these loci will be an essential goal to understanding the cellular basis of lung tumors and for developing strategies for the next generation of diagnostic and therapeutic studies.