Recent studies have shown that angiogenesis may be involved in the pathogenesis of hematopoietic malignancies, apart from its well-characterized role in the growth and metastasis of solid tumors. In this study, we quantified the degree of angiogenesis in B cell chronic lymphocytic leukemia (B-CLL) by measuring the microvessel density and hotspot density in bone marrow trephine biopsy sections with B-CLL involvement (n ‫؍‬ 12) and compared it to normal bone marrow sections (n ‫؍‬ 11). The B-CLL samples had a mean microvessel count/high power field (hpf) of 7.64 while the control samples had a mean microvessel count/hpf of 2.11 (P ‫؍‬ 0.0001). The mean hotspot density in the B-CLL sections (14.83/hotspot) was also significantly higher (P ‫؍‬ 0.0008) than the mean hotspot density in control bone marrow sections (7.09/hotspot). Both the microvessel density and hotspot density correlated positively with the clinical stage of the B-CLL patients. In a separate cohort of B-CLL patients, the median urine level of the angiogenic peptide, basic fibroblast growth factor (2216.5 pg/g, n ‫؍‬ 14), was significantly higher (P ‫؍‬ 0.0001) than the bFGF level in normal controls (1084 pg/g, n ‫؍‬ 58). These results indicate that angiogenesis may be involved in the pathogenesis of B-CLL.

SCA1 is an adult-onset, dominantly inherited neurodegenerative disease caused by expansion of a glutamine repeat tract in ATXN1. Although the precise function of ATXN1 remains elusive, it appears to play a role in transcriptional repression. We find that mutant ATXN1 suppresses transcription of the neurotrophic and angiogenic factor VEGF. We also show that genetic or pharmacologic replenishment of VEGF mitigates SCA1 pathogenesis, suggesting a novel therapeutic strategy for this incurable disease.

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Recent studies indicate that angiogenesis is important in the pathogenesis of leukemias, apart from its well-established role in solid tumors. In this study, the possible role of angiogenesis in acute promyelocytic leukemia (APL) was explored. Bone marrow trephine biopsies from patients with APL showed significantly increased microvessel density and hot spot density compared with normal control bone marrow biopsies.