PGR and neoplasm: Therefore, balancing efficacy and toxicity is a major challenge, and the optimal choice of chemotherapy must be driven by patient and disease characteristics such as menopausal status, oestrogen and progesterone receptor status, Her-2 neu expression (Gralow, 2005), and tumour characteristics such as p53 gene involved in tumour response to therapy (Vogelstein et al, 2000).