Study of the Expression of Angiogenic Factors and Dopaminergic Receptors: Correlation with ZAP70, CD38 and the Mutational State in Chronic Lymphocytic Leukaemia (CLL).

The angiogenesis is a well known process implicate in the progression of CLL. In this disease has been described an increase of angiogenic and pro-angiogenic factors in serum and angiogenic receptors in B cells, mainly in advances stages. Recently had been known that the agonist of the dopaminergic receptor D2 can inhibit the tumour growth and a possible mechanism mediator is the internalization of VEGFR-2. The aim of this work had been to analyze the expression of the dopaminergic receptors (D1, D2, D3, D4 and D5), the angiogenic receptors and its correlation with the main biological factor implicated in the illness (ZAP-70, CD38 and the mutational status of IgVH/BCL-6). We had determinate the levels of the receptors VEGFR-1, VEGFR-2, VEGFR-3 and c-kit, the angiogenic factor bFGF and the dopaminergic receptors D1, D2, D3, D4 and D5 in B lymphocytes from peripheral blood of 29 patients with CLL in A stage (using positive selection and quantitative PCR), and we had analyzed the possible correlation with the values of CD38 and ZAP70 and the mutational status of IgVH/BCL-6 (using flow cytometry and direct sequenciation).

Results: The lymphocytes B-CLL show a significant increment of the expression of the receptors VEGFR-1, VEGFR-2 and c-kit versus normal lymphocytes B. The patients with positive ZAP70 (> 20%) show a higher expression of all the factors studied except D1. The difference is statistically significant for D5, VEGFR-2 and c-kit (3 ×), D2 and bFGF (2 ×). The patients with positive CD38 show an increment in the expression of D2 (1,4x) and bFGF (1,9x) versus patients with negative CD38. The patients with both ZAP70 and CD38 positive present a higher expression of D2 and bFGF (2,2x and 1,9x) versus negatives ZAP70 and CD38, which show higher expression of D1 (4,8x). We had not found significant correlations between the studied factor and the mutational status of IgVH and BCL-6, only D1 shows a higher expression (3,6x) in patients with mutations IgVH versus unmutated independently of the BCL-6 status.

Conclusion: The lymphocytes B-CLL in stage A of Binet show high levels of expression of the angiogenic receptors VEGFR-1, VEGFR-2 and c-kit, the dopaminergic receptors D1 and D2, and the angiogenic factor bFGF that are significant higher that in normal lymphocytes B. The biological factor of bad prognostic (ZAP-70 and CD38) in patients in the initial A stage are associated with a higher expression of the receptors VEGF-R, c-kit, and D2 and the factor bFGF. Oppositely, negatives ZAP-70 and CD38 have correlation with the elevated expression of the receptor D1. This patron of differential expression can contribute to the tumoral progression of the patients in the initial stage of the illness.