PTPRC and prostate carcinoma: 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.