Table 1.

Comparison of predicted ratios of resistant clone sizes and ratios obtained from clinical data

Patient	$Y_1$*	$Y_2$	$Y_3$	$Y_4$	$Y_1/Y_2$	$Y_1/Y_3$	$Y_1/Y_4$
1	168	90			1.87
2	129	120			1.08
3	82	80	30		1.03	2.73
4	948	120	104	100	7.9	9.12	9.48
5	28	15			1.87
6	114	40			2.85
7	6,760	4,940	4,100	3,900	1.37	1.65	1.73
8	220	30			7.33
9	848	374	135	133	2.27	6.28	6.38
10	61	25			2.44
11	244	83	57		2.94	4.28
12	429	400	100		1.07	4.29
13	394	13	4		30.31	98.5
14	308	265	208	139	1.16	1.48	2.22
15	130	13			10
16	28	13			2.15
17	131	45	12	11	2.91	10.92	11.91
18	250	173	58	31	1.45	4.31	8.06
Median from patients					2.21	4.3	7.22
Predicted median					2.51	4.12	5.74
Predicted median (order by size)					2.05	3.63	5.25

^*Number of circulating tumor DNA (ctDNA) fragments per milliliter ($Y_1$ to $Y_4$) harboring different mutations associated with resistance to anti-EGFR agents in colorectal cancer patients treated with EGFR blockade (29). Ratio of resistant clone sizes is given by the ratio of the ctDNA counts for any two resistance-associated mutations. We assumed that mutations with higher ctDNA counts in the patient data appeared before mutations with smaller ctDNA counts. We also report predicted median ratios obtained from computer simulations when clones are ordered by size (parameters: $b=0.25$, $d=0.181$, $M={10}^9$, $u=42\times {10}^{-9}$).