ROLE OF CYP19A1 GENE AMPLIFICATION AS A MECHANISM OF THERAPY RESISTANCE IN HORMONAL RESISTANCE METASTATIC BREAST CANCER PATIENTS

Breast cancer is the most frequent cancer among women. It is considered to be a highly heterogeneous disease, with distinctphenotypic and morphological profiles, causing very different clinical outcomes.
The CYP19A1 is used as a prognostic marker of breast cancer due to its genetic control in estrogen synthesis.
CYP19A1 is affected by prolonged use of aromatase inhibitors treatment, acquired resistance to hormonal therapy causes the tumor to relapse leading to metastatic breast cancers.
Aim of work
The potential role of CYP19A1 gene copy number and amplification state was evaluated as a causative mechanism for developing secondary resistance to hormonal therapy in hormonal resistant breast cancer patients.
Patients and methods
The study was conducted on 50 consecutively selected patients with recurrent and/or metastatic breast cancer presented to Clinical Oncology and Nuclear Medicine Department at Alexandria Main University Hospital.
• Formalin fixed paraffin embedded tissue (FFPE) from primary tumor at the time of diagnosis and tissue tumor biopsies during relapse (confirmed by histo-pathological examination) from breast, liver, skin or any other affected organ if possible.
• Tissue tumor DNA was extracted from FFPE.
• The copy number of CYP19A1 gene was determined by Real Time Quantitative Polymerase Chain Reaction (RQ – PCR) using Taqman copy number assay (Applied biosystems).