ORIGINAL ARTICLE

Endothelin-1 expression correlates with atypical histological features in mammary phyllodes tumours

Gary M Tse¹, Benjaporn Chaiwun², Kin-Mang Lau¹, Richard Scolyer³, C Soon Lee³, Rooshdiya Z Karim³, Thomas C Putti⁴, Bonita K Law⁵, Philip C Lui¹ and Puay Hoon Tan⁶

¹ Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong
² Department of Pathology, Chiang Mai University, Thailand
³ Department of Pathology, University of Sydney, and Department of Anatomical Pathology, Royal Prince Alfred Hospital, Sydney, Australia
⁴ Department of Pathology, National University Hospital, National University of Singapore, Singapore
⁵ The Breast Center, Union Hospital, Hong Kong
⁶ Department of Pathology, Singapore General Hospital, Singapore

Correspondence to:
Correspondence to:
Dr Gary M Tse
Senior Medical Officer, Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, Ngan Shing Street, Shatin, NT, Hong Kong SAR, China; garytse{at}cuhk.edu.hk

Background and Aims: Endothelin-1 expression is increased in infiltrating duct carcinoma and is associated with larger tumour size, higher histological grade and lymphovascular permeation. This has not been evaluated in phyllodes tumours, which are uncommon fibroepithelial lesions with potential for local recurrences or distant metastasis. While the grading of phyllodes tumours depends on a combination of histological parameters, prediction of their behaviour remains difficult.

Method: A large series of 461 phyllodes tumours (291 benign, 115 borderline malignant and 55 frankly malignant) were evaluated for endothelin-1 expression in both the epithelial cells and stromal cells by immunohistochemistry; results were correlated with the tumour grade.

Results: For benign phyllodes tumours, the epithelial staining of endothelin was negative, weak, moderate and strong in 6%, 26%, 15% and 53% of cases respectively; results were 4%, 18%, 19% and 59% respectively for borderline and 6%, 18%, 6% and 70% respectively for frankly malignant tumours. For the stromal staining, the negative, weak, moderate and strong staining was 32%, 19%, 18% and 31% respectively for benign phyllodes, 24%, 13%, 10% and 53% respectively for borderline and 8%, 16%, 17% and 59% respectively for frankly malignant tumours. There was correlation between epithelial and stromal staining, and the stromal staining correlated with histological features of stromal cellularity, stromal cell nuclear pleomorphism, margin status and stromal overgrowth.

Conclusion: These observations suggest a close relationship between the epithelial and stromal elements in phyllodes tumours; endothelin may play a significant role in the malignant progression of phyllodes tumours.

Abbreviations: ET, endothelin; ETR, endothelin receptor; VEGF, vascular endothelial growth factor

Keywords: breast; phyllodes tumour; endothelin

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?