Alkylation of Nucleic Acids and Carcinogenesis

Abstract

The idea that the induction of cancer might follow mutation of somatic cells was first put forward by Boveri in 1914¹. He suggested that the great frequency of mitotic abnormalities in cancers indicates an abnormal chromosome constitution which might be the primary cause of malignant change in the cells. The presence of visible chromosomal abnormalities is not, however, an essential feature of malignancy and the ideas of Boveri have been critically reviewed by Koller ² in the light of more recent cytological analysis. Koller points out that primary tumours always contain some cells of normal karyotype and that these may be the only type, particularly during the early stages of tumour development. Furthermore, there is evidence that mitotic abnormalities and cell heterogeneity in tumours may be the result of defective nutritional and blood supply within the tumour mass and thus a secondary effect rather than the primary cause of the malignant change. It seems, therefore, that morphologically detectable chromosome abnormalities have not been established as the cause of the neoplastic transformation but this does not exclude chromosomal changes which cannot be detected microscopically but which may occur in the induction of point mutations.