Cyclo-oxygenase-2 (COX-2) mRNA expression and hormone receptor status in breast cancer

Abstract 

Aims

The purpose of this study was to evaluate COX-2 mRNA expression with known clinical prognostic features of breast cancer, oestrogen/progesterone receptor status, tumour size and grade.

Methods

Total RNA was extracted from 45 frozen breast tumour (invasive) and 22 normal breast tissue samples. COX-2 mRNA transcription was quantified using a real time RT-PCR assay and expressed as copy number/μg total RNA. All specimens were assessed for tumour grade, size, nodal status and presence of vascular invasion and oestrogen and progesterone receptor status.

Results

COX-2 mRNA was detected in all samples with a median copy number of 1.15×10⁷ for tumours and 6.5×10⁶ for normal samples. Expression was significantly higher in oestrogen receptor negative tumours compared to the receptor positive group. There was no correlation between COX-2 mRNA levels and tumour size, grade, nodal status and presence of vascular invasion.

Conclusions

COX-2 mRNA expression is increased in oestrogen and progesterone receptor negative breast cancers.

Keywords: Cyclo-oxygenase (COX), Oestrogen receptor (ER), Progesterone receptor (PgR), Non-steroidal anti-inflammatory drug (NSAID), Human epidermal growth factor receptor-2 (HER-2)