Tumor suppressor genes play a major role in the pathogenesis of human lung cancer and other cancers. Cytogenetic and allelotyping studies of fresh tumor and tumor-derived cell lines showed that cytogenetic changes and allele loss on the short arm of chromosome 3 (3p) are most frequently involved in about 90% of small cell lung cancers and greater than 50% of non-small cell lung cancers. A group of recessive oncogenes, Fus1, 101F6, Gene 21 (NPRL2), Gene 26 (CACNA2D2), Luca 1 (HYAL1), Luca 2 (HYAL2), PL6, 123F2 (RaSSFI), SEM A3 and Beta* (BLU), as defined by homozygous deletions in lung cancers, have been located and isolated at 3p21.3.