الفهرس 
WORLD HEALTH ORGANIZATIONOnly 14 pages are availabe for public view
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Abstract
T
he B-cell chronic lymphocytic leukemia (CLL) is a disease with a very low proliferative activity. It is characterized by the accumulation of clonal B-lymphocytes that seem to be arrested in early G0/G1 phase of the cell-cycle. Although the pathogenesis of B-CLL remains largely unknown, several investigators have focused on the role of cytogenetic aberrations that may contribute to defective apoptosis, deregulation of cell-cycle regulatory genes and expansion of the malignant clone.
Despite its homogeneity at cellular level, B-CLL is clinically heterogeneous. Some patients survive for a long-time without therapy, while others progress towards more advanced stages and die despite aggressive treatment. Reliable prognostic markers capable of predicting the progression and outcome of the disease include chromosomal analysis by conventional cytogenetics and interphase FISH, CD38 expression, ZAP-70 and examination of bone marrow infiltration pattern.
Clonal chromosomal aberrations are detected in about 40-50% of B-CLL patients. Recently, higher percentages were documented when using molecular techniques such as fluorescence in-situ hybridization (FISH), polymerase chain reaction (PCR), and comparative genomic hybridization (CGH).
Therefore, this study aimed to evaluate patients with a clinical diagnosis of CLL by immunophenotyping (IP), conventional karyotyping and FISH technique for the following chromosomal abnormalities: trisomy 12 (+12), 17p (p53) deletion and 14q32 rearrangement (IgVH). Documented chromosomal abnormalities were correlated with IP and clinical outcome of the disease.
To fulfill this aim, the present study included 35 B-CLL patients; 22 males and 13 females, with male to female ratio of 1.7: 1. Their ages ranged from 40-80 years, with a mean of 58.77 ± 10.96 years.
In the present study, conventional cytogenetic analysis (CCA), using G-banding, yielded successful karyotyping in 26/35 (74.3%) of studied CLL patients. Out of the 26 patients with successful mitosis, 17/26 (65%) had chromosomal abnormalities. Trisomy 12 was detected in 6/26 (23.1%). Five out of 26 patients (19.2%) had del 13q14, 2/26 (7.7%) had del 6q, 2/26 (7.7%) had 11q rearrangement and 2/26 (7.7%) of cases had 14q32 rearrangement.
In the current work, re-evaluation by FISH analysis revealed that +12 was detected in 9/35 (25.7%), del 17p (p53) in 11/35 (31.4%), and 14q32 rearrangement in 6/35 (17.1%) of studied CLL patients, in comparison to 6/35 (17.1%), 0/35(0%), 2/35(5.7%) by G-banding technique, respectively.
In the present work, positive B-CLL cases for +12 were shown to be associated with known poor predicted prognosis, as well as, poor disease outcome. Patients positive for + 12 showed a statistically significant association, with a number of poor clinical and laboratory prognostic parameters: splenomegaly (p = 0.01), higher BM lymphocytes % (p < 0.0001), low platelets count (p = 0.004), short LDT (p = 0.004), advanced Rai clinical staging (p = 0.003), higher expression of CD38 (p < 0.0001) and FMC7 (p < 0.0001) on their lymphocytes. Trisomy 12 was not significantly associated with lower Hb. The +12 was the only chromosomal abnormality associated with disease outcome in the present work. It could be associated with a more proliferative disease, an aggressive clinical course, poorer prognosis and disease outcome, that is probably due to amplification of MdM2 gene.
Patients positive for 14q32 rearrangement had statistically significant association, with shorter LDT (p = 0.03), lower Hb level (p = 0.03), and advanced Rai clinical staging (p = 0.04).
Patients positive for p53 deletion had statistically significant association with shorter LDT (p = 0.009), lower Hb level (p = 0.02), higher expression of CD38 (p = 0.01), CD79b (p = 0.03), FMC7 on their lymphocytes (p=0.002), advanced Rai clinical staging (p = 0.02).
Patients with 17p (p53) deletion and 14q32 rearrangement were found to be associated with known poor predicted prognosis, poor clinical outcome, but no statistical significant association with disease outcome.
Multivariate forward stepwise logistic regression was used to detect prognostic variables, capable of predicting prognosis among all studied parameters (age, Hb, TLC, PLT, absolute PB lymphocytes, BM lymphocytes, sex, Rai stage, hepatomegaly, splenomegaly, lymphadenopathy, CD79b, CD38, FMC7, LDT, +12, 14q32 rearrangement and p53 deletion). The LDT was the best single-variable, among prognostic factors, that predicted the disease outcome. It was the single predictor of disease response, with 85.7% of patients correctly classified as good or poor outcome disease. Adding Hb to LDT correctly classified 94.3% of CLL patients. When sex was added to LDT and Hb, 94.3% of patients were correctly classified. Further processing did not add any value.
In conclusion, +12, 17p (p53) deletion and 14q32 rearrangement expression were detected in 74.3% of studied B-CLL patients and were associated with poor predicted prognosis of CLL. Trisomy 12 was the only chromosomal abnormality associated with poor disease outcome. The FISH technique possessed the upper hand in detection of specific targeted aberrations in comparison to CCA. Nevertheless, conventional karyotyping remained the cornerstone in cytogenetic analysis because of its ability to simultaneously scan for various aberrations affecting many chromosomal loci (del 13q, del 6q and del 11q) as well as complex karyotypes (+12/p53, 14q32/p53).
Therefore, the present study recommended the use of Hb and LDT, for first-line CLL screening for prognosis, in Egypt and other developing countries, especially with the superimposed world-wide financial crises. These two simple parameters are available in all clinics and even in the smallest peripheral labs country-wide and world-wide. Thus, the use of other sophisticated techniques like FISH technique is advisable to be done as a second-line screening in those prognostically unclassifiable patients, and to confirm the prognosis, in a University-Hospital or a research lab.