Coinvolgimento della proteina HS1 nella sopravvivenza dei linfociti B neoplastici di pazienti con leucemia linfatica cronica

B-cell chronic lymphocytic leukemia (B-CLL) is the most common form of leukemia in adults and is characterized by the accumulation of clonal CD5+ B lymphocytes due to uncontrolled growth and resistance to apoptosis. Several protein kinase pathways have been claimed to be involved in the regulation of cell survival. We previously demonstrated that the Src kinase Lyn is overexpressed, constitutively active and anomalously distributed in malignant B cells as compared to normal B lymphocytes. Our attention was subsequently focused on the 75 kDa HS1 protein, which is one of the major substrate of Lyn kinase upon BCR cross-linking and plays a crucial role in BCR-induced apoptosis in the mouse B lymphoma cell line WEHI-231. In the present study HS1 protein level was measured by western blotting analysis in 43 untreated B-CLL patients and in 26 normal controls. We found a significant difference in HS1 protein level between CLL and normal B cells, being mainly expressed in the leukemic patients with respect to normal controls (p