Cytogenetic Alterations During Malignant Transformation
Interest in the degree of chromosomal stability of normal cells in vitro and in the same cells under conditions leading to “malignant transformation” obviously relates to various theories of cancer which can be assembled under the term “somatic mutation.” Only in the past 7 or 8 years have techniques been available for adequate studies of mammalian chromosomes. The comments of Schultz (18) are appropriate in this regard: “It is a truism by now that the change from the normal to the neoplastic cell must involve a change in cellular heredity. However, this statement is now so general as to be meaningless; it demands a rephrasing in concrete terms and a more definite conceptual analysis.” Schultz pointed out that alternative hypotheses often consist of nothing more than restatements “specified in terms of a particular phenotype” which also applies to the viral theory of tumorigenesis. The virus may act only at one point during infection and its subsequent loss would be immaterial since it functions as an initiator, an agent of gene or structural mutation. Viral DNA may possibly become incorporated into the mammalian host cell genome in the manner of lysogenic systems but again this can be classified as a special case of a somatic cell mutation.
KeywordsSyrian Hamster Contact Inhibition Unit Character Polyoma Virus Human Diploid Cell
Unable to display preview. Download preview PDF.
- 1.Aula, P.: Virus-associated chromosome breakage. A cytogenetic study of chickenpox, measles and mumps patients and of cell cultures infected with measles virus. Ann. Acad. Sci. Fenn. Series A, IV Biologica #89:1–75 (1965).Google Scholar
- 2.Defendi, V.: Transformation in vitro of mammalian cells by polyoma and simian 40 viruses. Prog. in Exp. Res. 8, in press. Google Scholar
- 3.Defendi, V., and Lehman, J. M.: Transformation of hamster embryo cells in vitro by polyoma virus: morphological, karyological, immunological and transplantation characteristics. J. Cell. & Compar. Physiol. Dec. (1965).Google Scholar
- 7.Girardi, A. J., Weinstein, D., and Moorhead, P. S.: SV40 transformation of human diploid cells: Parallel studies of viral and karyological parameters. Annales Medicinae Experimentalis et Biologiae Fenniae, in press (1966).Google Scholar
- 8.Harnden, D. G.: Cytogenetic studies on patients with virus infections and subjects vaccinated against yellow fever. Amer. J. Human Genetics 16:204–213 (1964).Google Scholar
- 19.Shein, H. M., and Enders, J. F.: Multiplication and cytopathogenicity of simian vacuolating virus 40 in cultures of human tissues. Proc. Soc. Exp. Biol. & Med. 109:495–500 (1962).Google Scholar
- 20.Shein, H. M., Enders, J. F., Palmer, L., and Grogan, E.: Further studies on SV40-induced transformation in human renal cell cultures. I. Eventual failure of subcultivation despite a continuing high rate of cell division. Proc. Soc. Exp. Biol. & Med. 115:618–621 (1964).Google Scholar