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. 2017 Jul 17;13(7):e1005660. doi: 10.1371/journal.pcbi.1005660

Correction: Parameter estimation for multistage clonal expansion models from cancer incidence data: A practical identifiability analysis

Andrew F Brouwer, Rafael Meza, Marisa C Eisenberg
PMCID: PMC5513402  PMID: 28715500

Table 1 and Figs 4, 5, 7, 8 and 10 are incorrect. There is an error in the value of the threshold used to calculate the confidence intervals. The authors have provided the corrected versions here.

Table 1. Best-fit parameters and likelihood-based 95% confidence intervals.

Best-fit parameters and likelihood-based 95% confidence intervals for the fits of the two-, three-, and four-stage clonal expansion models (with parameterizations using only practically identifiable parameter combinations and given in Eqs. (2), (9), and (11) respectively) to age-specific incidence of pancreatic cancer.

Model Parameter combination Value Likelihood-based 95% CI
Two-stage
p2=12((αβμ1)(αβμ1)24αμ1) -1.29E-1 (-1.32E-1, -1.26E-1)
q2=12((αβμ1)+(αβμ1)24αμ1) 6.21E-6 (5.58E-6,6.88E-6)
r2 = vX/α 1.50E-2 (1.38E-2,1.65E-2)
Three-stage
p3=12((αβμ2)(αβμ2)24αμ2) -1.38E-1 (-1.42E-1,-1.34E-1)
q3=12((αβμ2)+(αβμ2)24αμ2) 1.57E-5 (1.38E-5,1.76E-5)
r3=νXμ1/α 2.35E-2 (2.23E-2,2.49E-2)
Four-stage
p4=12((αβμ3)(αβμ3)24αμ3) -1.50E-1 (-1.57E-1,-1.43E-1)
q4=12((αβμ3)+(αβμ3)24αμ3) 4.59E-5 (3.90E-5,5.32E-5)
r3 = (vXμ1μ2)1/3 2.66E-2 (2.54E-2,2.80E-2)

Fig 4. Two-stage model profile likelihoods.

Fig 4

Profiles of the relative negative log-likelihood (NLL) of the two-stage clonal expansion model as each of the parameter combinations p2, q2, and νX/α are varied while the remaining parameters are fit. The gray dotted line gives the α = 0.05 threshold for simultaneous confidence intervals based on the relative negative log-likelihood. All three parameters are identifiable.

Fig 5. Three-stage model profile likelihoods.

Fig 5

Profiles of the relative negative log-likelihood (NLL) of the three-stage clonal expansion model as each of parameter combinations p3, q3, νX, and μ1 are varied while the remaining parameters are fit. The gray dotted line gives the α = 0.05 threshold for simultaneous confidence intervals based on the relative negative log-likelihood. Parameter combinations p3 and p4 are identifiable, while νX and μ1 are practically unidentifiable.

Fig 7. Profile likelihood for the reparameterized combination of the three-stage model.

Fig 7

Profile of the relative negative log-likelihood (NLL) as the parameter r3=νXμ1/α varied while the remaining parameters are fit in the three-stage clonal expansion model. The gray dotted line gives the α = 0.05 threshold for simultaneous confidence intervals based on the relative negative log-likelihood. Parameter combination r3 is identifiable.

Fig 8. Four-stage model profile likelihoods.

Fig 8

Profiles of the relative negative log-likelihood (NLL) of the four-stage clonal expansion model as each of parameter combinations p4, q4, νX, μ1, and μ2 are varied while the remaining parameters are fit. The gray dotted line gives the α = 0.05 threshold for simultaneous confidence intervals based on the relative negative log-likelihood. Parameter combinations p4 and q4 are identifiable, while νX, μ1, and μ2 are practically unidentifiable.

Fig 10. Profile likelihood for the reparameterized combination of the four-stage model.

Fig 10

Profile of the relative negative log-likelihood (NLL) as the parameter r4 = (νXμ1μ2)1/3 is varied while the remaining parameters are fit in the four stage clonal expansion model. The gray dotted line gives the α = 0.05 threshold for simultaneous confidence intervals based on the relative negative log-likelihood. Parameter combination r4 is identifiable.

Reference


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