Table 1.
Model Parameters
Parameter | Description | Colorectal Cancer With Specific Gene Targets* | Colorectal Cancer With Pathway Gene Targets** |
---|---|---|---|
k | rate-limiting stages | 5 driver gene mutations | 6 pathway mutations |
m | number of crypts | 15,000,000 | 15,000,000 |
n | stem cells per crypt | 40 | 8 |
u | target mutation rate | 1 × 10-6 per gene per division | 3 × 10-6 per pathway per division |
d | divisions since birth | once every four days | once every four days |
p | probability of cancer | - | - |
*In this model, five specific driver genes must be mutated for transformation
**In this model, six driver genes must be mutated for transformation, but because multiple genes in the same pathway are functionally equivalent, the mutational target or numbers of base pairs at risk are larger than when mutations must occur in specific driver genes.