Study On Chromosomal Aberrations In Chronic Lymphocytic Leukemia By Interphase Fluorescence In Situ Hybridization And Their Association With Clinical Features

Background:Chronic lymphocytic leukemia (CLL) is a kind of malignant proliferative disease of lymphatic system.The cumulation of small and seemed mature lymphocytes in peripheral blood,bone marrow and lymphoid tissues is a characteristic of the CLL. In the Western countries,it is the most common form of leukemia in adults.And in our country and other Asia area, the incidence is lower (about 5% in all kinds of leukemia),while it becomes more and more higher in recent years. The number of dividing leukenic cells is so small, chromosomal aberrations were detected by cytogenetic analysis approach in only 40% to 50% of patients, that a definite diagnosis is difficult to make. While to observe the curative effect and detect minimal residual disease are more difficult. The fluorescence in situ hybridization (FISH) overcomes a lot of limitations of routine techniques, it can detect many genes at the same time,tell the difference of the complex chromosomal translocation and minimal deletion,and discriminate polyploid and hyperdiploid in interphase cells. So, Sequence-specific DNA probes (D13S25, RBI, p53, ATM), and one centromeric probe CSP12, were applied to detect del(13ql4), del(17p13), del(11q22-q23) and trisomy 12 using interphase fluorescence in situ hybridization(I-FISH) in order to tell the relationships between cytogenetic abnormalities and clinical features in patients of CLL.Purpose:To investigate the common chromosomal aberrations in CLL and find the relationship between these abnormalities and clinical features of CLL by I-FISH with sequence-specific DNA probes (D13S25, RBI, p53, ATM), and one centromeric probe CSP12.Methods:Nine CLL patients with negative conventional cytogenetics (CC) or without mitotic figure, admitted to the department of Hematology in Qilu hospital from April, 2005 to April,2008, were enrolled in this study. The diagnostic criteria accords to edited chiefly by Zhang Zhinan (third edition). And we collected several clinical features of these patients, including gender, age, stages (Rai stage and Binet stage), had bulky lymphadenopathy or not, lymphocytes in bone marrow (BM), and white blood cells (WBC), hemoglobin (Hb), platelet (PLT), albumin (ALB), lactate dehydrogenase (LDH) in peripheral blood (PB),and the follow-up months. The samples of ten patients without hematopoietic malignancies are controls.Sequence-specific DNA probes (D13S25, RB1, p53, ATM), and one centromeric probe CSP12, were applied to detect del(13ql4), del(17p13), del(11q22-q23) and trisomy 12 using interphase fluorescence in situ hybridization. The threshold was established using 10 controls without hematopoietic malignancies.Results:Compared with the threshold based by 10 controls without hematopoietic malignancies, if the result detected higher than the threshold, it would be positive, otherwise would be negative. All of the 9 CLL patients showed cytogenetic abnormalities. P53 and D13S25 were found abnormal in 7 cases, while 5 abnormal cases for ATM and 4 abnormal cases for both RB1 and CSP12. There was significant correlation between the ATM and the hemoglobin level of the patients. In addition, the ATM abnormal patients indicated an elevated probability of gaining bulky lymphadenopathy.Conclusions:1,I-FISH is a more rapid and sensitive technique for analysis of chromosome aberrations in CLL.2,There was significant correlation between the ATM and the hemoglobin level of the patients. In addition, the ATM abnormal patients indicated an elevated probability of gaining bulky lymphadenopathy. 3,A large series study with long-term follow-up is needed to reveal the role of cytogenetic abnormalities in the determination of prognosis of CLL.