الفهرس 
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Abstract
The 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 homogenecity 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). Therefore, this study aimed to evaluate patients with a clinical diagnosis of CLL by FISH technique for the following chromosomal abnormalities: 6q21 deletion and c-Myc amplification in addition to the common aberrations (trisomy 12, 13q14 del, 11q23 del and p53 {17p13} deletion. Documented chromosomal abnormalities were correlated with standard prognostic factors and clinical outcome of the disease.
To fulfill this aim, the present study included 37 B-CLL patients; 23 males and 14 females, with male to female ratio of 1.6: 1. Their ages ranged from 49 to 75 years, with a mean of 61.4 ±6.5 years. Two ages matched healthy volunteers were used as controls; to check the signals of the used probes.
Patients fulfilling all the following criteria were selected:
1. PB persistent absolute lymphocytosis (>5x109/L) for at least 3 months period
2. A characteristic Immunophenotyping pattern of: CD5+, CD19+ (CD5/CD19 co-expression), CD23+, restricted К or light chain expression. Patients showing negative CD23 and CD5 expression were excluded.
All patients were subjected to the following:
- Thorough clinical history and examination.
- Radiological investigation, including:
1. Plain chest x-ray.
2. Abdominopelvic ultra-sound for lymphadenopathy and organomegaly.
- Laboratory investigation, including:
1. CBC, using Coulter LH 750.
2. Examination of Leishman-stained PB and BM smears.
3. Immunophenotyping by whole blood lysis using routine panel for LPD.
4. Fluorescence in situ hybridization analysis (FISH) using locus specific identifier (LSI) probe for detection of 6q21 deletion / c-Myc (8q24) amplification {Cat.# KBI-10109} in addition to the routine panel for CLL (CEP 12, LSI 13q14, LSI 17p13{p53}). Presence of any one of the following known poor prognostic parameters, at the time of diagnosis, was used to classify patients into predicted favorable and unfavorable disease outcome: High TLC (≥ 100 x109/L), Advanced clinical stage according to Rai classification (stage III or IV), Positivity for CD38 and/or FMC7 expression, del 17p, or trisomy 12.
In the present work, positive B-CLL cases for 6q21 deletion were 7/37 (18.9%) patients and showed significant association with poor predicted prognosis (p=0.031). Positive patients for 6q21 deletion showed a statistically significant association, with a number of poor clinical and laboratory prognostic parameters: low Hb level (p=0.006), high total leucocytic count (p<0.001), low platelets count (p =0.002), short LDT (p = 0.031), advanced Rai clinical staging (p <0.001), higher expression of CD38 (p<0.001).
Patients positive for c-Myc amplification were 10/37 (27%) patients and showed association with poor predicted prognosis (p=0.006). Patients positive for c- Myc amplification had statistically significant association, with lower Hb level (p =0.024), high TLC (p =0.043) and shorter LDT (p =0.006).
Deletions in 13q14 were 14/37(37.8%), trisomy 12 were in 9/37(24.3%), and finally deletion 17 q (P53) were in 3/37(8.1%). We found a higher incidence of 13q14 deletion in cases with favorable outcome (p<0.001). On the contrary, +12 was significantly associated with a number of poor laboratory prognostic parameters and poor outcome (p=0.007). While there was no association found between p53 deletion and the predicted prognosis at time of diagnosis (p=0.275).
In our study, there was a statistical association between the outcome of disease and some standard prognostic markers. There was clinical significance between old age (p<0.001), sex (p=0.021), and advanced Rai staging (p=0.008), LDT (p<0.001), and CD38 expression (p<0.001)
In conclusion, 6q21 deletion and c- Myc amplification identify subgroup of CLL patients, associated with poor predicted prognosis. LDT, staging, CD38 expression and cytogenetic profile are valuable for first-line CLL screening for prognosis.