Questions 1 and 2 refer to the following case:

A 72-year-old man with no significant past medical history presents for evaluation of fatigue. On physical exam he appears pale and has palpable cervical lymphadenopathy as well as splenomegaly. Laboratory testing reveals a white blood cell (WBC) count of 35,000/µL with a hemoglobin level of 5.6 g/dL and a platelet count of 86 × 10³/µL. Review of the peripheral blood smear shows a predominance of WBCs with pale blue cytoplasm, prominent nucleoli, and serrated hair-like projections.