Because assay validation was completed during the late stages of this trial, we performed a pilot analysis of putative mixed E/M-phenotype CTCs in 13 of the final patients enrolled, employing MUC1 as a tumor marker as has been done in several prior CTC studies [43–45], and enumerating and measuring p16 expression in VIM+, MUC1+, DAPI+, and CD45– cells from peripheral blood specimens. The gene discussed is PTPRC; the disease is neoplasm.