Cancer represents the phenotypic end-point of multiple genetic lesions that endow cells with a full range of biological properties required for tumorigenesis.  Indeed, a hallmark genomic feature of many cancers, including, for example, lung cancer, breast cancer, ovarian cancer, and colon cancer, is the presence of numerous complex chromosome structural aberrations—including non-reciprocal translocations, amplifications and deletions. 
Karyotype analyses (Johansson, B., et al. ( 1992) Cancer 69, 1674-81; Bardi, G., et al. ( 1993) Br J Cancer 67, 1106-12; Griffin, C. A., et al. ( 1994) Genes Chromosomes Cancer 9, 93-100; Griffin, C. A., et al. ( 1995) Cancer Res 55, 2394-9; Gorunova, L., et al. ( 1995) Genes Chromosomes Cancer 14, 259-66; Gorunova, L., et al. ( 1998) Genes Chromosomes Cancer 23, 81-99), chromosomal CGH and array CGH (Wolf M et al. ( 2004) Neoplasia 6(3)240; Kimura Y, et al. ( 2004) Mod.  Pathol.  21 May (epub); Pinkel, et al. ( 1998) Nature Genetics 20:211; Solinas-Toldo, S., et al. ( 1996) Cancer Res 56, 3803-7; Mahlamaki, E. H., et al. ( 1997) Genes Chromosomes Cancer 20, 383-91; Mahlamaki, E. H., et al. ( 2002) Genes Chromosomes Cancer 35, 353-8; Fukushige, S., et al. ( 1997) Genes Chromosomes Cancer 19:161-9; Curtis, L. J., et al. ( 1998) Genomics 53, 42-55; Ghadimi, B. M., et al. ( 1999) Am J Pathol 154, 525-36; Armengol, G., et al. ( 2000) Cancer Genet Cytogenet 116, 133-41), fluorescence in situ hybridization (FISH) analysis (Nilsson M et al. ( 2004) Int J Cancer 109(3):363-9; Kawasaki K et al. ( 2003) Int J Mol.  Med.  12(5):727-31) and loss of heterozygosity (LOH) mapping (Wang Z C et al. ( 2004) Cancer Res 64(1):64-71; Seymour, A. B., et al. ( 1994) Cancer Res 54, 2761-4; Hahn, S. A., et al. ( 1995) Cancer Res 55, 4670-5; Kimura, M., et al. ( 1996) Genes Chromosomes Cancer 17, 88-93) have identified recurrent regions of copy number change or allelic loss in various cancers.  For example, in lung cancer, frequent gains have been mapped to 1q31, 3q25-27, 5p13-14 and 8q23-24 and losses to 3p21, 8p22, 9p21-22, 13q22, and 17p12-13 (Bjorkqvist, A. M., et al. ( 1998) Br J Cancer 77, 260-9; Luk, C., et al. ( 2001) Cancer Genet Cytogenet 125, 87-99; Pei, J., et al. ( 2001) Genes Chromosomes Cancer 31, 282-7; Petersen, I., et al. ( 1997) Cancer Res 57, 2331-5; Balsara, B. R. & Testa, J. R. (2002) Oncogene 21, 6877-83).  In some instances, validated oncogenes and tumor suppressor genes residing within these loci have been identified, including MYC (8q24), p16INK4A (9p21), RB1 (13q14), RASSF1 (3p21), TUSC2 (3p21), SEMA3B (3p21), FHIT (3p14), and KRAS2 (12p12).  However, for the majority of amplified and deleted loci and resident genes, the presumed cancer-relevant targets remain to be discovered.