Immunoexpression of MED12 in lobular carcinoma in situ confined within fibroadenoma of breast

Fibroadenomas are common lesions in young women. Approximately 60–80% of fibroadenomas harbor a somatic mutation in exon 2 of the mediator complex MED12 subunit. MED12 regulates physiologic processes important for cell development. Dysregulation of MED12 has been described as linked to estrogen and...

Full description

Saved in:
Bibliographic Details
Published in:Human Pathology Reports Vol. 42; p. 300804
Main Authors: Perry, James W., Iczkowski, Kenneth A., Pantazis, Cooley G., Burns, Amanda M.
Format: Journal Article
Language:English
Published: Elsevier Inc 01.11.2025
Elsevier
Subjects:
Breast
Fibroadenoma
Lobular carcinoma in situ
MED12
Mediator
Pathology
MED12
Breast
Mediator
Lobular carcinoma in situ
Fibroadenoma
ISSN:2772-736X, 2772-736X
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Fibroadenomas are common lesions in young women. Approximately 60–80% of fibroadenomas harbor a somatic mutation in exon 2 of the mediator complex MED12 subunit. MED12 regulates physiologic processes important for cell development. Dysregulation of MED12 has been described as linked to estrogen and TGF-β signaling. MED12 subunit mutations in fibroadenomas localize to the stromal cells and not the epithelial cells. Frequent MED12 subunit mutations have been detected in breast cancer as well as estrogen-dependent benign tumors, such as fibroadenoma, uterine leiomyoma, and phyllodes tumor. An association of lobular carcinoma in situ with fibroadenoma has been reported. The LCIS in this case was entirely confined to the fibroadenoma. This is the first reported case of immunohistochemical overexpression of MED12 in LCIS arising within a fibroadenoma.
ISSN:2772-736X
2772-736X
DOI:10.1016/j.hpr.2025.300804