4. Histologically proven primary triple negative breast cancer as defined as oestrogen receptor (ER) negative, progesterone receptor (PgR) negative (if available, otherwise PgR unknown), (as defined by Allred score 0/8 or 2/8 or stain in <1% of cancer cells) and human epidermal growth factor receptor 2 (HER2) negative (immunohistochemistry 0/1+ or negative by in situ hybridization) as determined by local laboratory.