Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.

[Q]: Bone, as well as the lung and liver, is among the sites of predilection for cancer metastasis. The bone stores large amounts of growth factors such as insulin-like growth factors and transforming growth factor-b, and provides fertile soil for metastatic cancer cells by continuously releasing these bone-stored growth factors, which are a consequence of osteoclastic bone resorption. Metastatic cancer cells in turn produce osteoclast-stimulating cytokines such as parathyroid hormone-related protein( PTH-rP), prostaglandin E2.(PGE2), and various interleukins(ILs). These cancer-produced osteoclast-stimulating cytokines bind to their cognitive receptors and promote the expression of ligands for the receptor activators of nuclear factor kB (RANKL)in osteoblasts. RANKL then binds to its receptor RANK, expressed in pre-osteoclasts, stimulates mature osteoclast formation, and subsequently, osteoclastic bone resorption. This vicious cycle between metastatic cancer cells and osteoclasts is critical to the development and progression of bone metastases. In addition, it is likely that metastatic cancer cells are influenced by bone environments(or niche)and acquire additional capacities such as an epithelial-mesenchymal transition(EMT), allowing them to be resistant to chemotherapy or apoptosis, to survive in a dormant state, or to aggressively spread to distant organs including lung and liver. Thus, the bone can serve as transit port. Disrupting this cycle by inhibiting osteoclastic bone resorption, antagonizing bone-derived growth factors, and neutralizing RANKL or PTH-rP, should be a promising therapeutic intervention for bone metastases. Bisphosphonates(BP)are specific inhibitors of osteoclasts, and have been shown to significantly reduce skeletal-related events(SRE)associated with bone metastasis. Denosumab is a neutralizing monoclonal antibody to RANKL and has recently been found to inhibit SRE more effectively than BP. Further understanding of the crosstalk communication between metastatic cancer cells and bone at the molecular level should lead us to design novel, more effective and specific treatments for cancer patients with bone metastases.
[A]: To the ligand of which receptors does Denosumab (Prolia) bind?


[Q]: Mutaib bin Abdullah bin Abdulaziz Al Saud (Arabic: , Mutib bin Abd Allah bin Abd al-Aziz Al Suud, alternative spelling Miteb) (born 26 March 1952) is a member of House of Saud who has served as Saudi Arabia's Minister of the National Guard since 27 May 2013.
[A]: What was the noble family that Mutaib bin Abdullah was from?


[Q]: The immune system usually protects you from pathogens and other causes of disease. When the immune system is working properly, it keeps you from getting sick. But the immune system is like any other system of the body. It can break down or develop diseases. AIDS is an infectious disease of the immune system caused by a virus. Some diseases of the immune system are noninfectious. They include autoimmune diseases and allergies. Does it make sense for an immune system to attack the cells it is meant to protect? No, but an immune system that does not function properly will attack its own cells. An autoimmune disease is a disease in which the immune system attacks the bodys own cells. One example is type 1 diabetes. In this disease, the immune system attacks cells of the pancreas. Other examples are multiple sclerosis and rheumatoid arthritis. In multiple sclerosis, the immune system attacks nerve cells. This causes weakness and pain. In rheumatoid arthritis, the immune system attacks the cells of joints. This causes joint damage and pain. Autoimmune diseases cannot be cured. But they can be helped with medicines that weaken the immune systems attack on normal cells. Other autoimmune diseases include celiac disease (damages to the small intestine), inflam- matory bowel disease (damage to the digestive tract), psoriasis (damage to the skin), and lupus (damage to the joints, skin, kidneys, heart, and lungs). An allergy occurs when the immune system attacks a harmless substance that enters the body from the outside. A substance that causes an allergy is called an allergen. It is the immune system, not the allergen, that causes the symptoms of an allergy. Did you ever hear of hay fever? Its not really a fever at all. Its an allergy to plant pollens. People with this type of allergy have symptoms such as watery eyes, sneezing, and a runny nose. A common cause of hay fever is the pollen of ragweed. Many people are also allergic to poison ivy ( Figure 1.2). Skin contact with poison ivy leads to an itchy rash in people who are allergic to the plant. Ragweed is a common roadside weed found throughout the United States. Many people are allergic to its pollen. Some people are allergic to certain foods. Nuts and shellfish are common causes of food allergies. Other common causes of allergies include: Drugs, such as penicillin. Mold. Dust. The dead skin cells of dogs and cats, called dander. Stings of wasps and bees. Most allergies can be treated with medicines. Medicines used to treat allergies include antihistamines and corticos- teroids. These medicines help control the immune system when it attacks an allergen. Sometimes, allergies cause severe symptoms, a condition known as anaphylaxis. For example, they may cause the throat to swell so it is hard to breathe. Severe allergies may be life threatening. They require emergency medical care.
[A]:
hay fever is an allergy to