Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Example Input: Context: Chronic myeloid leukemia (CML) arises as a consequence of a chromosomal translocation giving rise to the Philadelphia chromosome and Bcr-Abl oncogene. CML is a clonal disease of stem cell origin and an excellent example of a malignancy in which tumor-initiating cells may hold the key to disease eradication. The known molecular basis of CML has enabled the development of Abl-specific tyrosine kinase inhibitors, such as imatinib mesylate. However, the success of tyrosine kinase inhibitors, as rationally designed first-line therapies, has been tempered by problems of disease persistence and resistance. Residual disease has been shown to be enriched within the stem cell compartment and to persist at stable levels for up to 5 years of complete cytogenetic response. This finding has led to further searches for novel strategies aimed at eliminating these cells; such strategies may be essential in achieving cure. The most significant recent findings are discussed in this review. 
 Question: What tyrosine kinase, involved in a Philadelphia- chromosome positive chronic myelogenous leukemia, is the target of Imatinib (Gleevec)?
Example Output: bcr-abl

Example Input: Context: Spleen tyrosine kinase (Syk) is an important modulator of immune signaling. The objective of this phase 2 study was to evaluate the efficacy and safety of R788, an oral inhibitor of Syk, in patients with active rheumatoid arthritis despite methotrexate therapy. We enrolled 457 patients who had active rheumatoid arthritis despite long-term methotrexate therapy in a 6-month, double-blind, placebo-controlled trial. The primary outcome was the American College of Rheumatology (ACR) 20 response (which indicates at least a 20% reduction in the number of both tender and swollen joints and improvement in at least three of five other criteria) at month 6. R788, at a dose of 100 mg twice daily and at a dose of 150 mg once daily, was significantly superior to placebo at month 6 (ACR 20 response rates of 67% and 57%, respectively, vs. 35%; P<0.001 for the comparison of both doses with placebo). It was also significantly superior with respect to ACR 50, which indicates at least a 50% improvement (43% and 32% vs. 19%; P<0.001 for the comparison of the 100-mg dose with placebo, P=0.007 for the comparison of the 150-mg dose with placebo) and ACR 70 (28% and 14% vs. 10%; P<0.001 for the comparison of the 100-mg dose with placebo, P=0.34 for the comparison of the 150-mg dose with placebo). A clinically significant effect was noted by the end of the first week of treatment. Adverse effects included diarrhea (in 19% of subjects taking the 100-mg dose of R788 vs. 3% of those taking placebo), upper respiratory infections (14% vs. 7%), and neutropenia (6% vs. 1%). R788 was associated with an increase in systolic blood pressure of approximately 3 mm Hg between baseline and month 1, as compared with a decrease of 2 mm Hg with placebo; 23% of the patients taking R788 vs. 7% of the patients receiving placebo required the initiation of or a change in antihypertensive therapy. In this phase 2 study, a Syk inhibitor reduced disease activity in patients with rheumatoid arthritis; adverse events included diarrhea, hypertension, and neutropenia. Additional studies will be needed to further assess the safety and efficacy of Syk-inhibition therapy in patients with rheumatoid arthritis. (Funded by Rigel; ClinicalTrials.gov number, NCT00665925.) 
 Question: Which enzyme is inhibited by a drug fostamatinib?
Example Output: spleen tyrosine kinase

Example Input: Context: An annoying problem for humans, who like to boast about all the distant planets and moons we have explored, is that we've never taken a good look right under our noses. The inside of the earth is relatively close, but how can we get there? The deepest oil well enters a mere six miles into the crust (the center of the earth is about 4,000 miles deeper). Russian scientists dug the deepest hole in Siberia, but bottomed out at about 7.5 miles below the surface. The Mohole project, a U.S. plan in the 1950s, called for drilling a hole 25 miles down to the boundary between the hard rocks of the crust and the soft mantle . Sadly the project involved government supporting. It gets harder and harder to drill deep into the earth because rocks get softer and softer. Hard but easily broken at the surface, rocks become plastic at depth, and the pressure caused by the weight of the overlaying crust --- about 52,800 pounds per square inch at a depth of ten miles, makes further drilling impossible. What little we know about the inside of the earth (like the fact that there's a crust, a mantle, and a core) comes from indirect evidence, such as the analysis of earthquakes. So maybe it's time for a thorough new method to explore the earth's inside. Scientist David Stevenson says we should forget about drilling holes. Instead, we should open a crack . Stevenson suggests digging a crack about a half mile long, a yard wide, and a half mile deep (not with a shovel) but with an explosion on the scale of a nuclear bomb. Next, he'd pour a few hundred thousand tons of molten iron into the crack, along with a robot. The iron, thicker than the surrounding crust, would move downward at about 16 feet per second, carrying the robot with it and opening the crack deeper and deeper. The iron mass would drop for about a week and 2,000 miles to the outer edge of the earth core, the robot sending out data to the surface. Stevenson compares his idea to space exploration. "We're going somewhere we haven't been before,"he says. "In all possibility, there will be surprises." This idea can probably be put in the drawer marked with Isn't Going To Happen. The robot would have to survive temperatures that would melt pretty much anything. But Stevenson's idea may inspire a new look at an old problem. Great things can come from what seems like impossible ideas. 
 Question: How deep have we gone into the earth until now?
Example Output:
7.5 miles.