Background: Breast cancer is a major cause of cancer-related death in women and is increasing in incidence. Although this tumor generally appears in sporadic form, between 5 and 10% of cases can be considered hereditary, attributable to inherited mutations in several susceptibility genes. However, evidence on the effect of breast cancer susceptibility gene 1 (BRCA1) or BRCA2 mutation on prognosis is inconsistent.
Materials and methods: Sixty Egyptian women under the age of 40 years were studied. Archival formalin-fixed paraffin-embedded breast cancer tissues were obtained from pathology files. The histopathology and grade of the tumor were assessed. Immunohistochemical study and RNA extraction were also performed. Cells from the MCF-7 cell line grown in Roswell medium and known to express BRCA1 were processed in paraffin and used as positive controls for both immunohistochemical analysis and real-time reverse transcription-PCR. A study was performed to compare the expression of prognostically meaningful immunohistochemical markers such as estrogen receptors, progesterone receptor, HER-2, and CK5/6 in tumor cells of young female patients with breast cancer with or without mutation in the BRCA1 gene.
Results: Alteration in BRCA1 mRNA expression was found in 40% of cases. A positive relationship was demonstrated between lack of BRCA1 expression and high histological grade, negative estrogen and progesterone receptor status, and overexpression of HER-2 in breast cancer tissues.
Conclusion: The study demonstrated an inverse relationship between BRCA1 expression and parameters that determine poor prognosis in breast cancer.