PTEN and neoplasm: As a consequence, the PTEN gene is frequently targeted by deletions and mutations in tumors, and heterozygous PTEN mutations are found in the germline from patients with hamartomas and tumor predisposition (PHTS).16,23–25 Aberrant alterations in PTEN cytoplasmic/nuclear localization have also been found in tumors and in the germline of PHTS patients,26–32 making important for precise diagnosis not only the detection of the protein in tumor samples, but also its location in the cell.