Prognostic value of the human antigen R (HuR) in human breast cancer: high level predicts a favourable prognosis.

Background: The role of human antigen R (HuR) and its prognostic value in breast cancer is currently only partially understood. This study aimed to determine the levels of expression of HuR in breast cancer and assess its prognostic value. Materials and Methods: HuR expression levels were assessed in a cohort of human breast cancer specimens and cell lines using both quantitative and qualitative analysis along with immunohistochemical techniques and the results were compared to the patient details. Results: Immunohistochemical staining revealed a weak HuR staining pattern in breast tumour sections compared to the intense epithelial staining of the normal breast tissues. The levels of HuR transcripts were lower in the more advanced TNM4 and TNM3, poor outcome NPI-2 (Nottingham Prognostic Index) and NPI-3 and node-positive tumours compared with the early stage TNM2 and TNM1, NPI-1, and node-negative tumours, although these values did not reach statistical significance. The patients with metastasis, those who died of breast cancer and those with bone metastasis had significantly decreased levels of HuR transcripts, (p=0.031, p=0.018 or p=0.038 respectively) compared to the disease-free patients. The patients with poor prognosis, including those with metastasis and those who died of breast cancer, had a significantly lower level of HuR transcripts compared to the disease-free patients (p=0.021). High levels of HuR correlated with longer overall survival, although the values did not reach statistical significance (p=0.06). Conclusion: While no significant association of the levels of HuR expression with pathological status of breast cancer is reported, HuR may represent a prognostic factor in human breast cancer, as patients expressing high levels of HuR have a favourable prognosis, and the prognostic role of HuR for breast cancer metastasis, particularly bone metastasis is supported.