Endometrial hyperplasia versus carcinoma: does phosphatase and tensin homolog immunohistochemical expression differentiate between them

Context
Phosphatase and tensin homolog (PTEN) is a protein that acts as a tumor suppressor by dephosphorylating the lipid second messenger phosphatidylinositol 3,4,5-trisphosphate. Loss of PTEN function and mutation in gene have been implicated in the pathogenesis of endometrial carcinoma (EC).
Objective
The aim was to evaluate the immunohistochemical expression of PTEN in endometrial hyperplasia and EC and to evaluate the relationship between its expression and tumor grade in EC.
Materials and methods
Specimens included 16 cases of endometrial hyperplasia without atypia, six cases of atypical endometrial hyperplasia, and 18 EC specimens. Immunohistochemical staining for PTEN was performed using diaminobenzidine detection kit on formalin-fixed and paraffin-embedded tissue samples. Tumor tissue blocks and clinical data were collected from the files of the Pathology Department of Al-Zahraa University Hospital during the period 2010–2014.
Results
Immunohistochemistry showed that PTEN was positive for nuclei and cytoplasm of glandular endometrial cells. The PTEN expression was decreased significantly in atypical hyperplasia or EC compared with simple or complex hyperplasia (0.041). In EC, we proved that PTEN expression is downregulated in high-grade tumors.
Conclusion
A positive PTEN expression correlates significantly with hyperplasia without atypia and well-differentiated tumors. The downregulation of PTEN indicates a more malignant phenotype.