We analyzed the expression levels of PTPNs in the TCGA database and discovered that PTPN1, PTPN6, PTPN7, PTPN18, PTPN20, and PTPN22 were significantly upregulated in tumor samples, while PTPN4, PTPN5, PTPN10, PTPN11, PTPN13, PTPN14, and PTPN21 were downregulated in tumor samples (Figure 1A). Here, PTPN21 is linked to neoplasm.