In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.
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Question:  Keywords included reperfusion injury , transplantation , liver resection , nitric oxide , endothelin , cytokines , Kupffer cells , ischemic / ischaemic preconditioning , and nuclear factor - kappa B .

Answer: nuclear factor


Question:  Expression of oestrogen and progesterone receptors by mast cells alone , but not lymphocytes , macrophages or other immune cells in human upper airways .

Answer: progesterone receptors


Question:  The association of cytosol oestrogen and progesterone receptors with histological features of breast cancer and early recurrence of disease .

Answer:
progesterone receptors