Intercellular signalling plays an important role in the progression of a transformed cell to a tumour. In order to characterise the underlying mechanisms, a well-defined model cell system of intercellular induction of apoptosis was used where neighbouring normal cells can selectively eliminate transformed cells. In the absence of non-transformed cells, the induction of apoptosis in transformed 208Fsrc3 cells occurs via autocrine destruction and is dominated by peroxidase (PO), which initiates...