Claims of Diploid Cancer Analyzed
There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
Mark Twain 1883
Life on the Mississippi
From time to time there are reports of diploid cancer, as for example “diploid” colon cancers with mismatch repair deficiency [1]. But, further analysis of what appeared to be diploid colon cancers by “array-based comparative genomic hybridization” has since indicated that about “5% of their entire genome” is segmentally aneuploid versus 20% of a control group of colon cancers without mismatch repair deficiency [2]. Colon cancers with “normal karyotypes” have also been described by Bardi et al. [3]. But, further scrutiny reveals that these normal karyotypes were either from “hyperplastic polyps” [4] or from “nonneoplastic stromal cells” [5] or were considered to be misidentified tumor cells, showing “how dependent findings in solid tumor cytogenetics are on method” [6] (Bardi G., personal communication, 2004). Thus there is currently no unambiguous evidence for diploid cancer.
1. Lengauer C, Kinzler KW, Vogelstein B (1998) Genetic instabilities in human cancers. Nature 396: 643-649.
2. Nakao K, Mehta KR, Fridlyand J, Moore DH, Jain AN, et al. (2004) High-resolution analysis of DNA copy number alterations in colorectal cancer by array-based comparative genomic hybridization. Carcinogenesis 25: 1345-1357.
3. Bardi G, Fenger C, Johansson B, Mitelman F, Heim S (2004) Tumor karyotype predicts clinical outcome in colorectal cancer patients. J Clin Oncol 22: 2623-2634.
4. Bardi G, Parada LA, Bomme L, Pandis N, Willen R, et al. (1997) Cytogenetic comparisons of synchronous carcinomas and polyps in patients with colorectal cancer. Br J Cancer 76: 765-769.
5. Bardi G, Johansson B, Pandis N, Bak-Jensen E, Orndal C, et al. (1993) Cytogenetic aberrations in colorectal adenocarcinomas and their correlation with clinicopathologic features. Cancer 71: 306-314.
6. Bomme L, Bardi G, Pandis N, Fenger C, Kronborg O, et al. (1998) Cytogenetic analysis of colorectal adenomas: karyotypic comparisons of synchronous tumors. Cancer Genet Cytogenet 106: 66-71.