PTPRZ1 and neoplasm: To address the question, if Rptpζ would also act as a tumor suppressor in human OS, we first analyzed copy number data sets (CytoScan Arrays) from 160 human OS samples for chromosomal alterations around the PTPRZ1 locus on chromosome 7q31.3, yet we did not detect any specific changes supporting a contribution of PTPRZ1 loss to OS development or severity.