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Journal of Biomedicine and Biotechnology
Volume 2009, Article ID 369129, 7 pages
Research Article

Clinical Significance of Epigenetic Inactivation of hMLH1 and BRCA1 in Tunisian Patients with Invasive Breast Carcinoma

1Unitéde Génétique du cancer et Production de protéines thérapeutiques, Centre de Biotechnologie de Sfax, route Sidi Mansour, BP “1177”, 3018 Sfax, Tunisia
2Centre Hospitalo, Universitaire Habib Bourguiba, 3000 Sfax, Tunisia

Received 14 February 2009; Accepted 19 May 2009

Academic Editor: Xin-yuan Guan

Copyright © 2009 Sondes Karray-Chouayekh et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Aberrant hypermethylation of gene promoter regions is one of the mechanisms for inactivation of tumour suppressor genes in many human cancers including breast carcinoma. In the current study, we aimed to assess by MSP, the methylation pattern of two cancer-related genes involved in DNA repair: hMLH1 (mutL homolog 1, colon cancer, nonpolyposis type 2 (E. coli) and BRCA1 (breast cancer 1, early onset) in 78 primary breast cancers from Tunisian patients. The methylation frequencies were 24.36% for hMLH1 and 46% for BRCA1. BRCA1 methylation correlated with age at diagnosis ( ) and 5-years disease free survival ( ) while hMLH1 methylation was more frequent in larger tumors ( ) and in presence of distant metastasis ( ). Furthermore, methylation of hMLH1 significantly correlated with high level of P53 expression ( ) and with overall survival ( ) suggesting that silencing of hMLH1 through aberrant promoter methylation could be used as a poor prognosis indicator in breast cancer.