Neutral tumor evolution?

According to this traditional model, the selective advantage is conferred by a small set of driver mutations, but as the subclones that bear them successively expand, they also accumulate passenger mutations, which can be detected in sequencing experiments1. Genomes of individual tumors contain hundreds to many thousands of these genetic variants at a wide range of frequencies5,6. Because genetic drift can drive novel variants to high frequencies, it is of great interest to discern the relative importance of selection and drift in shaping the frequency distribution of variants in any given tumor. [...] the deterministic model of tumor growth described by Williams et al. relies on strong biological assumptions, including synchronous cell divisions, constant cell death, and constant mutation and division rates. [...]discrimination of neutral and non-neutral simulated tumors by using a linear fit is almost arbitrary, with 53.5% false-positive neutral calls in nonneutral tumors (Fig. 1b) and an area under the receiver operating characteristic curve of 0.42 for the classification of 1,919 neutral and 1,919 non-neutral tumors (Fig. 1c).