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

[Q]: In chronic lymphocytic leukemia (CLL) signals from the B cell receptor (BCR) play a major role in disease development and progression. In this light, new therapies that specifically target signaling molecules downstream of the BCR continue to be developed. While first studies on the selective small molecule inhibitor of Bruton's tyrosine kinase (Btk), Ibrutinib (PCI-32765), demonstrated that Btk inhibition sensitizes CLL cells to apoptosis and alters their migratory behavior, these studies however did not address whether Btk-mediated signaling is involved in the process of CLL leukemogenesis. To investigate the requirement of Btk signaling for CLL development, we modulated Btk expression in the IgH.ET CLL mouse model, which is based on sporadic expression of the simian oncovirus SV40 T-antigen in mature B cells. To this end, we crossed IgH.ET mice on a Btk-deficient background or introduced a human Btk transgene (CD19-hBtk). Here we show that Btk deficiency fully abrogates CLL formation in IgH.ET mice, and that leukemias formed in Btk haplo-insufficient mice selectively expressed the wild-type Btk allele on their active X chromosome. Conversely, Btk overexpression accelerated CLL onset, increased mortality, and was associated with selection of non-stereotypical BCRs into CLL clones. Taken together, these data show that Btk expression represents an absolute prerequisite for CLL development and that Btk mediated signaling enhances leukemogenesis in mice. We therefore conclude that in CLL Btk expression levels set the threshold for malignant transformation.
[A]: What is the name of Bruton's tyrosine kinase inhibitor that can be used for treatment of chronic lymphocytic leukemia?


[Q]: The Nimrud ivories are carved ivory plaques and figures dating from the 9th to the 7th centuries BC that were excavated from the Assyrian city of Nimrud (in modern Ninawa in Iraq) during the 19th and 20th centuries.
[A]: What is the surface of Nimrud ivories made of?


[Q]: In the first four years of the Chavez presidency, the economy grew at first (19992001), then contracted from 20012003 to GDP levels similar to 1997. At first, the economic decline was due to low oil prices, but it was fueled by the turmoil of the 2002 Venezuelan coup detat attempt and the Venezuelan general strike of 200203. Other factors of the decline were an exodus of capital from the country and a reluctance of foreign investors. GDP was 50.0 trillion bolivares in 1998. At the bottom of the recession in 2003, it was 42.4 trillion bolivares (in constant 1998 bolivares). However, GDP rebounded 50.1 trillion bolivares with a calmer political situation in 2004 and rose to 66.1 trillion bolivares in 2007 (both in constant 1998 bolivares).
[A]:
Was the GDP smaller in 2004 or in 2007?


