Clinicopathological Significance of Metallothioneins in Breast Cancer

Rongxian JIN1, Jingxiang HUANG1, Puay-Hoon TAN2, Boon-Huat BAY1

1Department of Anatomy, National University of Singapore, Singapore
2Department of Pathology, Singapore General Hospital, Singapore


Metallothioneins (MTs) are a family of metal binding proteins that play an important role in maintaining transition metal ion homoeostasis, redox balance in the cell and fundamental cellular processes such as proliferation and apoptosis. In humans, there are 4 groups of MT proteins which are encoded by 10 functional MT isoforms. In breast tissues, MT is primarily expressed in myoepithelial and malignant epithelial cells. Immunohistochemical studies have revealed that 26% to 100% of invasive ductal breast cancers express the MT protein. The MT-1F and MT-2A isoforms have been reported to be associated with higher histological grade in breast cancer, whereas higher MT-1E mRNA expression was found in estrogen receptor-negative tumors compared to their estrogen receptor-positive counterparts. A number of studies have shown that MT expression in breast cancer is associated with poorer prognosis. In addition, metallothionein expression may have a potential role in protecting the breast cancer cell from chemotherapeutic threats to survival. Pathology & Oncology Research, Vol 10, Nr 2, 74-79, 2004

Key words: MT isoforms; biochemistry; biomarker; prognosis; chemoresistance; carcinogenesis

Received: May 3, 2004; accepted: May 21, 2004
Correspondence: Boon-Huat BAY, Department of Anatomy, National University of Singapore, 4 Medical Drive, Block MD10 S 117 597, Singapore; Tel: (65) 6874 6139, Fax: (65) 6778 7643; E-mail:

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