In order to further investigate the heterogenous CD45-/CK+ positive CTC populations observed at four sequential time points during the treatment of our metastatic castrate-resistant prostate cancer patient (mCRPC) described in our previous report [30], we applied an additional phenotypic marker (vimentin), along with additional molecular approaches, and improved analytics, to previously unstained slides from that index patient. This evidence concerns the gene PTPRC and prostate cancer.