Control of the cell cycle.

Cell biology has made major progress in identifying the molecules that drive the cell cycle. The evidence accumulating from these studies indicates that derangements in the cell cycle machinery contribute to the uncontrolled cell growth of tumours. The cell cycle machinery has been found to be substantially altered in tumour cells and also may be crucial for carcinogenesis. In this context, various aspects of tumour cell growth have been studied in an effort to understand 1) why tumour cells display uncontrolled growth, 2) why radiation selectively affects growing cells, and 3) whether aspects of the cell cycle and tumour cell growth may be used in tumour diagnosis and prognosis.