One of the major limitations is that PTEN assessment lacks consistency and reproducibility across studies in terms of type of assay (immunohistochemistry versus next-generation sequencing), antibodies for immunohistochemistry testing, scoring system (e.g., H-score, protein levels, % of positive cells), cutoffs for PTEN-loss definition, and origin of tumor samples (primary versus metastatic samples). This evidence concerns the gene PTEN and neoplasm.