Increases in the proportion of p16-expressing V+ CTCs were measured in just 2 of the 22 patients evaluable for p16+V+ CTC prevalence (9%)—a substantially lower prevalence than that observed for p16 re-expression in CK+ CTCs and consistent with the lack of p16 expression modulation observed in tumor p16 IHC analysis (Table 4; Supplementary Fig. S7). This evidence concerns the gene CDKN2A and neoplasm.