In agreement with the findings of Su et al. (2018), we find that mutation of TP53, which is commonly associated with tumor initiation in many cancers (see, e.g., Yu et al. (2014) [37]), is inferred to occur on the trunk of the tree with high probability in patient P1, but not on the trunk of the tumor tree of patient P2. The gene discussed is TP53; the disease is neoplasm.