The Leeuwenhoek Lecture, 1978 Bacteria as proper subjects for cancer research

Abstract
Cancers are clones of abnormal cells, arising presumably as the result of mutational or epigenetic alterations of gene expression. The kinetics of appearance of spontaneous cancers in populations of multiplying cells (i. e. the relation between age and cancer incidence) will therefore depend, among other things, on how these populations are organized and, in general, on the kinetics of the response of cells to prolonged mutagenesis. The organization of cell renewal in epithelia (i. e. the arrangement of cell lineages) is still rather obscure; in particular, it is not known to what extent the properties and organization of the stem cells tend to protect them from accumulating mutations. We have tried to mimic the arrangement of epithelia by attaching multiplying bacteria to filters. Study of mutagenesis in long-term cultures of such anchored bacteria has led to the discovery of some additional pathways for DNA repair which also appear to operate in mammalian cells.