Among the 4 patients evaluable for p16 protein expression changes in both CK+ CTCs and tumor biopsy specimens (patients 3010009, 3010013, 4010014, and 4010016), none showed appreciable modulation of tumor p16 expression by IHC, yet 3 had significant FdCyd-induced increases in the proportion of p16+CK+ CTCs (Table 4). Here, CDKN2A is linked to neoplasm.