PhD Scientific Days 2026

Poster Session 1.D - Pathological and Oncological Sciences

GPNMB Immunohistochemistry in the Diagnosis of Lymphangioleiomyomatosis

Előadó neve

Dr. Szalai, Fatime

Neptune code

KVGNAE

Előadó munkahelye

Department of Pathology and Experimental Cancer Research

Előadó telefonszáma

+36 30 859 8032

Előadó e-mail címe

fatie.salay@gmail.com

Az előadás címe

GPNMB Immunohistochemistry in the Diagnosis of Lymphangioleiomyomatosis

Szerző(k) neve és munkahelye

Fatime Szalai¹, Judit Pápay¹, Katalin Dezső¹, Levente Kuthi^1,2, Anna Sebestyén¹, Andras Khoor³, Ildikó Krencz¹

1: Department of Pathology and Experimental Cancer Research, Semmelweis University
2: Department of Surgical and Molecular Pathology, Tumor Pathology Center, National Institute of Oncology
3: Department of Laboratory Medicine & Pathology, Mayo Clinic, Jacksonville, Florida, USA

Bemutatás módja

Poszter

Szekció

Poster Session 1.D - Pathological and Oncological Sciences

Language of the presentation

Hungarian

Preferred session

Pathological and Oncological Sciences

Összefoglaló szövege

Introduction
Lymphangioleiomyomatosis (LAM), a rare pulmonary neoplasm classified as a perivascular epithelioid cell tumor (PEComa), is associated with the cystic destruction of the lung parenchyma, which may lead to respiratory failure. The pathological diagnosis of LAM is aided by positivity for smooth muscle and melanocyte markers; however, distinguishing it from other histological entities remains challenging in some cases, particularly in small biopsies. Glycoprotein non-metastatic melanoma protein B (GPNMB) has recently been identified as a sensitive and specific immunohistochemical marker for PEComas, but only a few cases of LAM have been studied to date.

Aims
The aim of our study was to determine the diagnostic value of GPNMB immunohistochemistry as an ancillary marker in a larger cohort of LAM samples.

Methods
Immunohistochemical analysis of GPNMB expression was performed on human LAM samples (N=15), histological entities potentially considered during differential diagnosis (N=30), and normal lung tissue (N=2). We used the H-score method to quantify staining intensity; an H-score greater than 100 was considered high.

Results
All LAM samples showed high cytoplasmic GPNMB expression, and cell membrane positivity was also observed in some areas. In contrast, histological mimics demonstrated no or low GPNMB expression. Considering the H-score threshold of >100, GPNMB immunohistochemistry demonstrated 100% sensitivity and specificity in identifying LAM in our cohort. Normal epithelial and mesenchymal elements of the lung parenchyma did not stain for GPNMB; however, weak to moderate expression was observed in alveolar macrophages in both normal and diseased lung tissues.

Conclusion
Based on our study, GPNMB immunohistochemistry is a highly sensitive and specific marker that may aid in the pathological diagnosis of LAM. Beyond its diagnostic value, GPNMB positivity in the membrane of LAM cells may predict the efficacy of GPNMB-targeted antibody-drug conjugates (e.g., glembatumumab vedotin) in the treatment of the disease. In addition, recent studies suggest that GPNMB may also serve as a potential serum marker and may indicate the extent of response to mTOR-inhibitor therapy.

Funding
Hungarian Pulmonology Foundation, EFOP‐3.6.3‐VEKOP‐16‐2017‐00009

University

Semmelweis University

Supervisor

Ildikó Krencz

Publication of my abstract

I do not give consent to the publication of my abstract on the website of the congress.

phd.section.field

in doctoral studies after complex exam (PhD)

Kind

Szabad

Status

elfogadva

Accepted presentation method

poszter

Előadás fájl jóváhagyás

nem rendelkezett róla

Előadó

8995

Start

17:06

End

17:09