Noise in gene expression gives rise to cell-to-cell variability in protein concentrations and is increasingly recognized as a key source of non-genetic differences between cells. Through single cell imaging, it has now been possible to demonstrate that pre-existing differences in the levels of signalling proteins determine whether the addition of an external death signal will kill a cell or not—and how fast. This has implications for understanding 'fractional killing' of tumour cells after chemotherapy, in which some but not all tumour cells die.
- Sabrina L. Spencer
- Suzanne Gaudet
- Peter K. Sorger
