Changes in endometrial PTEN expression throughout the human menstrual cycle.

Area of Science:

• Endocrinology
• Molecular Biology
• Gynecologic Oncology

Background:

• PTEN (phosphatase and tensin homolog) is a critical tumor suppressor gene frequently mutated in endometrial adenocarcinoma.
• Its product, a phosphatase, regulates cell cycle, apoptosis, and cell adhesion.
• Understanding PTEN's role in normal endometrium is vital, especially concerning hormone influence.

Purpose of the Study:

• To investigate PTEN expression in normal human endometrium under varying physiological steroid hormone levels.
• To determine the effect of progesterone and estrogens on PTEN expression patterns.
• To correlate PTEN expression with specific phases of the menstrual cycle.

Main Methods:

• Quantitative assessment of PTEN ribonucleic acid (RNA) levels using Reverse Transcription Polymerase Chain Reaction (RT-PCR).
• Localization and pattern analysis of PTEN protein expression via immunohistochemistry using a monoclonal antibody.
• Examination of endometrial tissue across proliferative and secretory phases of the menstrual cycle.

Main Results:

• PTEN RNA levels significantly increased in secretory endometrium compared to proliferative endometrium.
• Progesterone exposure correlated with increased PTEN levels.
• Immunohistochemistry revealed dynamic, coordinate stromal and epithelial PTEN expression patterns influenced by hormone status, with notable changes during decidualization.

Conclusions:

• Stromal and epithelial cells contribute to hormone-dependent regulation of PTEN expression in the endometrium.
• Normal patterns of PTEN expression are sensitive to hormonal fluctuations.
• Disruptions in hormonal balance may lead to aberrant PTEN expression, potentially impacting endometrial health.