Homogeneously staining chromosomal regions contain amplified copies of an abundantly expressed cellular oncogene (c-myc) in malignant neuroendocrine cells from a human colon carcinoma.
Two human neuroendocrine tumor cell lines derived from a colon carcinoma contain either numerous double minute chromosomes (COLO 320 DM) or a homogeneously staining marker chromosome (COLO 320 HSR). We found amplification and enhanced expression of the cellular oncogene c-myc in both COLO 320 DM and HSR cells, and we were able to show that the homogeneously staining regions of the COLO 320 HSR marker chromosome contain amplified c-myc. From previous and present karyotypes, it appears that the homogeneously staining regions reside on a distorted X chromosome. Therefore, amplification of c-myc has been accompanied by translocation of the gene from its normal position on chromosome 8 (8q24). Because double minute chromosomes were features of primary cultures from the original tumor, it seems reasonable to suspect that amplification of c-myc may have contributed to tumorigenesis.
D001079:Apudoma / Q000235:genetics*; D002874:Chromosome Mapping; D002875:Chromosomes / Q000648:ultrastructure; D003110:Colonic Neoplasms / Q000235:genetics*; D005784:Gene Amplification; D006801:Humans; D007621:Karyotyping; D009380:Neoplasms, Nerve Tissue / Q000235:genetics; D009857:Oncogenes; D014178:Translocation, Genetic