PTPN21 and neoplasm: Additionally, we also evaluated correlations between PTPN gene expression levels and the pathological stage of LUAD patients, and we discovered that expression levels of PTPN6 and PTPN13 were significantly correlated with the tumor stage of LUAD patients, while expression levels of PTPN1, PTPN5, and PTPN21 were not (Figure 5).