About 15%-20% of breast cancer is triple negative (TNBC), which carries a poor prognosis. Target molecules investigated in TNBC are, PARP (poly-ADP-ribose polymerase) inhibitor, EGFR (epidermal growth factor receptor) inhibitor and also androgen receptor.
Details of TNBC patients, with follow up till 2011; and retrievable pathological slides and blocks, were analysed for AR status. Slides were reviewed for AR status using Androgen receptor Monoclonal (F39.4.1clone) Mouse antibodies. Slides were de-paraffinised and hydrated. Antigen was heat-retrieved. Horse-radish-peroxidase was used with diamine-benzaldehyde for antibody detection. Androgen receptor positivity was read as percentage and intensity of nuclear staining. Nuclear expression >10% was taken as nuclear positive. All slides were interpreted by a single breast-onco-pathologist.
Of the TNBC patients who had follow up, 72 slides were reviewed for AR status. Three had nuclear AR expression and six had cytoplasmic expression. Mean follow up was 52.53 months. Five year PFS for AR negative was 80.41% and for AR positive 75%. Median PFS was 19.93 months. Cytoplasmic positive group were disease free at the end of follow up. Pre-menopausal, AR positive had five year PFS of 83.3%. Post-menopausal group had median PFS of 19.93 months. Higher grade had less AR expression. Node positive had 5 year PFS of 60%.
AR expression was seen in elderly, post-menopausal, node-positive group as claimed by MacGhan, and Lou et al. AR-positive patients had poor progression-free interval. Luminal androgen receptor (LAR) sub-type of TNBC is identified to have decreased relapse-free-survival and is believed to have AR signaling. Luminal androgen receptor sub-set, encompassing a poor-prognostic group, might be more sensitive to anti-androgen molecules, and can be the sub-set for targeted tailored treatment options, improving the poor outcomes.
Clinical trial identification
All authors have declared no conflicts of interest.