# Membranous E-Cadherin Expression in Different Subtypes of Pituitary Neuroendocrine Tumors and Its Association with Invasiveness

## TL;DR

This study found that low membranous E-cadherin expression is linked to increased invasiveness in pituitary tumors, suggesting it could be a useful biomarker.

## Contribution

The study identifies membranous E-cadherin as a potential biomarker for invasiveness in pituitary neuroendocrine tumors.

## Key findings

- Low membranous E-cadherin expression (IRS 1–2) was associated with higher odds of cavernous sinus invasion.
- mE-cad expression varied significantly across different PitNET subtypes and TF lineages.
- In gonadotroph tumors, low mE-cad expression correlated with significantly higher invasiveness.

## Abstract

Pituitary neuroendocrine tumors (PitNETs) are usually benign intracranial neoplasms that may exhibit invasion of the cavernous sinus, complicating surgery and increasing the risk of recurrence. This study aimed to investigate membranous E-cadherin (mE-cad) expression across PitNET subtypes and transcription factor (TF) lineages, including Pit-1 (pituitary-specific positive transcription factor 1), SF-1 (Steroidogenic Factor 1), and TPIT (T-box pituitary transcription factor), and its association with tumor invasiveness in sixty-nine patients. mE-cad expression was evaluated as the percentage of positive cells (0%, 1–10%, >10%) and by immunoreactive score (IRS). Staining intensity was scored as: 0, no staining; 1, weak; 2, moderate; 3, strong. The proportion of positive cells was scored as: 0, none; 1, <10%; 2, 10–50%; 3, 51–80%; 4, >80%. Mean mE-cad expression was 5.2% in gonadotroph, 3.2% in corticotroph, 0.5% in lactotroph, and 17.5% in plurihormonal PitNETs. By TF lineage, the mean expression was 5.3% for Pit-1, 3.2% for TPIT, and 5.1% for SF-1. Low mE-cad expression (IRS 1–2) was associated with higher odds of cavernous sinus invasion compared with IRS 3–6 (adjusted OR = 6.0, 95% CI 1.08–33.4, p = 0.04), independent of tumor volume (adjusted OR = 4.0, 95% CI 1.50–10.7, p = 0.01). After restricting the analysis to the gonadotroph PitNET group, tumors with an IRS of 1–2 showed significantly higher invasiveness compared with those with an IRS of 3–6 (p = 0.012). These findings suggest that mE-cad may serve as a biomarker of PitNET invasiveness, with expression varying according to TF lineage and tumor subtype.