Stem cells containing “×” mutations | ||
---|---|---|
“x” mutations | Random (genome-wide) | Cancer-associated genes |
1 | 1.47 × 10^{9} | 7.98 × 10^{6} |
2 | 7.35 × 10^{8} | 7.98 × 10^{3} |
3 | 2.45 × 10^{8} | 5 |
6 | 2.04 × 10^{6} | |
9 | 4.05 × 10^{3} | |
12 | 3 |
For these calculations, we have made the following assumptions: The spontaneous mutation rate for a gene is 2 × 10^{−7} per gene per division; stem cells divide 100 times in lifetime; the number of stem cells in the body is 4 × 10^{9}; a cell contains 5 × 10^{4} genes, but 100 cancer-associated genes. Probabilities were calculated by Poisson probability distribution. Populations were determined by multiplication of the probability by the number of stem cells.