Microvessel density and hot spot density in APL and control bone marrow biopsy specimens.

Microvessel density in diagnostic APL bone marrow biopsy specimens (▪, n = 12) was 7.0/hpf, whereas microvessel density in normal control bone marrow biopsy samples (■, n = 12) was 2.4/hpf (P = .0001). Hot spot density in APL bone marrow biopsy specimens (15.5/hot spot) was significantly (P = .0007) higher than in control bone marrow biopsy specimens (7.4/hot spot)