Some studies analyzing the prognostic value of PTPN12 in small cohorts of up to 250 patients report a positive correlation of increased PTPN12 expression and outcome in non small cell lung cancer [18], breast cancer [45] and squamous cell carcinoma [14], whereas Zhangyuan et al. found a contrary result in their study in at least one subgroup of non-hepatitis B-positive patients with hepatocellular carcinoma [11]. This evidence concerns the gene PTPN12 and breast cancer.