Further characterization of morphologically defined typical and atypical CLL: a clinical, immunophenotypic, cytogenetic and prognostic study on 390 cases

We analysed a group of 390 patients, diagnosed with chronic lymphocytic leukaemia (CLL). Cases were subclassified as morphologically typical and atypical CLL according to the criteria of the FAB proposal. Typical CLL cases were mostly diagnosed at a low-risk stage (Binet A/Rai 0), required no immediate treatment and expected a long survival; atypical CLL cases mostly presented at a more advanced risk stage (Binet B/Rai I–II), usually required immediate treatment and their survival was shorter. Moreover, clinical staging was of prognostic significance in typical but not in atypical cases.   In typical CLL, del(11q) was the most common chromosomal abnormality (21%) whereas in atypical CLL trisomy 12 was found in about 65% of the cases documented with an abnormal karyotype. Although chromosomal abnormalities were associated with a poor survival in typical CLL, they are of no prognostic significance in atypical CLL.   Based on these data, we conclude that subtyping CLL by morphology enables the identification of two groups of cases, each characterized by a specific clinical presentation, different cytogenetic abnormalities and prognostic parameters. We speculate that these two groups may represent two related, but different, diseases with different prognostic parameters and a different survival.     

Trisomy 12 is a Rare Event in Cases of CLL with Typical Immunophenotype and Morphology

131 patients with lymphoproliferative disorders were classified as having typical Chromic Lymphocytic Leukaemia [CLL], atypical CLL, Chromic Lymphocytic Leukaemia/Prolymphocytic Leukaemia [CLL/PL] or Non-Hodgkin's Lymphoma [NHL] using immunophenotyping and morphology. The incidence of trisomy 12 (+12) in each of the groups was ascertained using fluorescent in situ hybridization. Trisomy 12 was found to be rare in the typical CLL group (<3%) and more common in the atypical CLL (22%), CLL/PL (40%) and NHL (43%) categories. The low incidence of +12 in the typical CLL group is most likely due to our adherence to strict inclusion criteria to ensure other similar lymphoproliferative disorders, with a high incidence of +12, were excluded. This approach leads to more homogeneous disease categories and consequently may help to resolve issues such as the impact on survival of +12 in CLL.     

Trisomy 12 is uncommon in typical chronic lymphocytic leukaemias

The incidence of trisomy 12 was studied by conventional chromosome analysis in 111 patients referred as B-cell chronic lymphocytic leukaemia (B-CLL). Fluorescent in situ hybridization (FISH) was also applied in 34 of those patients with either a normal karyotype or no analysable mitoses. By karyotyping, trisomy 12 was present in 11.7% (13/111), whereas additional FISH increased the incidence to 14.4% (16/111). When subdividing our cases in either typical CLL (n= 90), fulfilling the FAB classification criteria, or atypical CLL (n= 21), with one or more variations from those criteria, the incidence of +12 by metaphase analysis was 3% and 48%, respectively. Additional FISH increased the incidence to 4% and 57%. The most common aberration in atypical CLL was FMC7 positivity (n= 11), followed by CD5 negativity (n= 8), strong surface immunoglobulin staining (n= 7) and atypical morphology (n = 6). Trisomy 12 could only be demonstrated in a small proportion of neoplastic cells in all positive cases. By FISH and/or karyotyping, all available samples at diagnosis of the disease were positive.     

p53 abnormalities in CLL are associated with excess of prolymphocytes and poor prognosis

To determine the role of the p53 gene in chronic lymphocytic leukaemia (CLL) and its possible involvement in the pathogenesis of a progressive form of CLL characterized by > 10% prolymphocytes (CLL/PL), we selected 32 cases, 17 with typical morphology and 15 CLL/PL. The extent of inactivation of p53 was examined by assessing loss of heterozygosity (LOH) at 17p13.3, by sequencing the highly conserved region (exons 5–9) of the p53 gene and by analysing p53 protein expression. LOH was detected in 8/28 (29%) cases, p53 mutations in 5/32 (16%) cases and p53 expression in 5/27 (19%) cases. Overall 11 cases (30%) had p53 abnormalities of which eight cases had CLL/PL. There was a significant association between CLL/PL and p53 abnormalities ( P  = 0.05); 75% of cases with LOH, 80% of p53 mutations and 80% of cases positive for p53 protein had CLL/PL. Thus, p53 inactivation is the first gene abnormality identified so far to be involved in the development of CLL/PL. All the cases with typical CLL and p53 abnormalities had only one allele affected whereas 4/6 CLL/PL had both alleles inactivated. This difference in the extent of p53 inactivation suggests that accumulation of p53 abnormalities may be associated with progression of CLL to CLL/PL.
CLL cases with p53 abnormalities were characterized by a higher incidence of stage C ( P  < 0.025), a higher proliferative rate ( P  = 0.05), short survival ( P  < 0.005) and resistance to first-line therapy ( P  < 0.02) but not to nucleoside analogues. Analysis of the correlation between p53 status and incidence of trisomy 12 by fluorescence in situ hybridization (FISH) showed that trisomy 12 was more frequent in cases without p53 abnormalities, suggesting that trisomy 12 and p53 may represent different pathways of transformation in CLL.     

Atypical lymphocyte morphology: an adverse prognostic factor for disease progression in stage A CLL independent of trisomy 12

We studied 270 patients with Binet stage A chronic lymphocytic leukaemia looking for adverse prognostic factors. In a multivariate analysis the following features were found to be risk factors for disease progression: atypical lymphocyte morphology (defined as either > 10% prolymphocytes or > 15% lymphocytes with cleaved nuclei or lymphoplasmacytoid cells); more than two karyotypic abnormalities; lymphocyte count > 30 × 10⁹/l; lymphocyte doubling time < 1 year; enlargement of one or more lymph node groups.
In a univariate analysis the presence of trisomy 12 also correlated with progressive disease, but this was largely a consequence of the association between trisomy 12 and atypical lymphocyte morphology. Atypical lymphocyte morphology is an important prognostic factor in stage A CLL, and one which incurs no additional investigational cost.     

Trisomy 12 is seen within a specific subtype of B-cell chronic lymphoproliferative disease affecting the peripheral blood/bone marrow and co-segregates with elevated expression of CD11a

In order to delineate the specific morphological and immunophenotypic features of B-cell lymphoproliferative disorders associated with trisomy 12, 172 sequential unselected cases of CD19⁺CD5⁺ B-cell disorders, primarily affecting the peripheral blood and bone marrow, were studied. Trisomy 12 was found in 24 cases (13.9%), with all cases morphologically classified as either CLL-PL or CLL-mixed by FAB criteria. Trisomy 12 was not found in any cases of typical CLL. Trisomy 12 cases demonstrated a significant higher expression of CD11a ( P <0.0001) and CD20 ( P <0.0006) when compared to cases with the equivalent morphology and immunophenotype, but without the chromosomal abnormality. Trisomy 12 cases also demonstrated a higher frequency of FMC7, CD38 expression and moderate to strong surface immunoglobulin staining. However, no correlation was detected between the percentages of trisomy 12 cells and cells expressing CD11a, CD38, FMC7 or sIg mean fluorescent intensity. Cells from trisomy 12 positive cases were sorted according to their CD11a expression using fluorescent activated cell sorting. There was a significant increase in the percentage of trisomy 12 cells within the CD11a⁺ sorted fraction compared to the unsorted population ( P <0.05), implying that trisomy 12 is associated with increased expression of CD11a.
With the highly specific morphological and immunophenotypic features demonstrated by trisomy 12 cases in this study, it is highly likely that these cases constitute a specific group of B-cell lymphoproliferative disorders.     

Atypical chronic lymphocytic leukaemia witht(ll;14)(ql3;q32): karyotype evolution and prolymphocytic transformation

Summary. In order to define better the cytological and clinical features of atypical B-cell chronic lymphocytic leukaemia (B-CLL) with t(ll;14)(ql3;q32), sequential morphologic immunological and cytogenetic studies were performed in seven patients belonging to a series of 72 consecutive cases presenting with a diagnosis of CLL or atypical CLL according to the FAB criteria. Cytologic diagnosis in these seven patients with t(ll;14) was typical CLL in two cases presenting with < 10% large lymphocytes (LL) and prolymphocytes (PL) and atypical CLL in five cases in which LL and PL comprised between 10% and 55%. The diagnosis was supported by histologic findings on bone marrow biopsy (five cases) or splenectomy specimens (two cases). A progressive increase of peripheral LL and PL was observed, resulting in a switch of FAB diagnosis over a 6-60-month period from typical CLL into atypical CLL in two cases and from atypical CLL into prolymphocytic leukaemia in five cases. Immunophenotyping showed a mature B-cell phenotype with CD19, CD22, CD24 positivity and CD10 negativity in all patients. A bright-staining pattern for surface immunoglobulins (SIg) was detected in 6/7 cases, CD5 positivity in 6/7 cases, and CD23 positivity in 1/7 cases. The FMC-7 monoclonal antibody was positive in >40% cells in 5/6 cases. Chromosome changes in addition to t(11; 14) were seen in five cases; in two cases unbalanced translocations involving the 3q21 chromosome region, resulting in partial trisomy for the long arm of chromosome 3, were detected early in the course of the disease. Karyotype evolution that was associated with disease progression occurred in 3/6 assessable patients. Comparison of these findings with similar data from 65 B-CLL patients without t(ll;14) showed that atypical morphology, switch of FAB diagnosis during the course of the disease, and karyotype evolution were more frequently seen in cases with t(ll;14) (5/7 v 15/65 cases, P = (V015, 7/7 v 7/65 cases, P < 0-0001, and 3/6 v 5/45 assessable cases, P= 0-04, respectively). The frequency of positivity for CD2 3 and bright SIg staining differed significantly in the two groups. It is concluded that t(ll;14) identifies a cytologically atypical subset of B-CLL, characterized by frequent cytologic and cytogenetic evolution and by a distinct immunological profile, sharing some biological features with mantle cell lymphoma.     

Chronic lymphocytic leukaemia profiled for prognosis using a fluorescence in situ hybridisation panel

A panel of fluorescence in situ hybridisation (FISH) probes was used on 894 cases to target chromosome 11q, 13q, 17p deletions (del), trisomy 12 (+12) in all and 6q deletion in 59. Chronic lymphocytic leukaemia (CLL) immunophenotype (CD5 and CD19 with CD23) was found in 509 cases (average age 67.7 years, 319 males and 190 females). Among the 509 CLL cases 349 (68.6%) had FISH (4-probe panel) abnormalities: 160 del 13q [45.8% (122-del 13q, 18-biallelic del 13q, 20-monoallelic/biallelic del 13q)], 71 tri 12 (20.3%), 17 del ATM (5%), 12 del p53 (3.4%) and 89 > or = 2 FISH abnormalities (25.5%). Of 151/509 cases karyotyped, 108 were normal and 43 (43/151 = 28.5%) abnormal. Del 6q was found in 1/59 (1.6%) FISH cases and in 6/151 (4%) karyotypes. In 14 CD23 negative cases IGH/BCL1 FISH detected t(11;14) and was confirmed to be mantle cell lymphoma. Multiple probes/panels that included IGH probe were ordered for 57 CLL cases, 11 had an IGH rearrangement with an unidentified partner. This study favours the inclusion of del 6q and IGH probes in the CLL panel. The FISH panel could also serve to monitor 13q deletion for secondary changes with adverse prognosis. Understanding prognosis in specific types of 13q deletion would enhance outcome prediction.     

Association and clonal distribution of trisomy 12 and 13q14 deletions in chronic lymphocytic leukaemia

The coexistence of trisomy 12 and deletions of chromosome 13 (13q12-q32) has rarely been observed in chronic lymphocytic leukaemia (CLL). Fluorescence in situ hybridization (FISH) performed on 600 consecutive CLL patients revealed the association of trisomy 12 and 13q14 deletion, of at least one of the three markers analysed (RB1, D13S319 and D13S25), in 55 cases (9% of 600 and 46% of 120 trisomy 12 cases). Trisomy 12 and isolated RB1 deletion were seen in 14/120 cases, trisomy 12 and D13S319/D13S25 deletion with diploid RB1 in 19/118, and trisomy 12 and deletion encompassing the three 13q markers studied in 22/118 cases. The heterogenous distribution of trisomy 12 and 13q deletions within the neoplastic B cells suggests that they are secondary rather than primary events in CLL leukaemogenesis.     

Deletion of chromosome 13 (band ql4) but not trisomy 12 is a clonal event in B-chronic lymphocytic leukaemia (CLL)

Summary. Chromosomal abnormalities are detected by conventional cytogenetic or FISH analysis in 50% of chronic lymphocytic leukaemias (CLL). Trisomy 12 and del 13ql4 account for 70% of these abnormalities. The incidence of these two abnormalities was studied in CLL patients by Southern blot analysis using a highly purified B-cell malignant population (CD5>95%, CD3 < 5%). Probes for the Dl 3S25 marker on chromosome 13 band ql4 and for the RBTN3 gene on chromosome 12 band pi2-13, were used. Deletion of the Dl 3S2 5 was detected in 17/42 patients (43%) in a homozygous (9-5%) or heterozygous (30%) configuration. Deletion of the D13S25 marker appears to be a clonal and early event in CLL development since it is detected in >95% of the malignant clonal population. Conversely, trisomy 12 is rarely a clonal event (5/33 patients, 15%) and a varying proportion of cells carrying this abnormality can be demonstrated in 30% of CLL patients (10/33 patients).     

Concurrent rearrangements of BCL2, BCL3, and BCL11A genes in atypical chronic lymphocytic leukemia

The most frequent chromosomal aberrations with the well established prognostic meaning in chronic lymphocytic leukemia (CLL) are +12, del(11q), del(13q), and del(17p). Less common translocations lead to deregulation of genes primarily due to juxtaposition with IGH gene.

We present a case of CLL patient with atypical morphology and an aggressive course of disease. In spite of aggressive treatment including allogeneic hematopoietic stem cell transplantation disease progressed into a rare cutaneous Richter's syndrome. Trisomy 12 was found as a sole chromosomal change at initial cytogenetic analysis of lymphoma cells. At progression, besides trisomy 12 three concomitant balanced translocations t(2;14)(p13;q32), t(14;19)(q32;q13), and t(18;22)(q21;q11) were found. The same karyotype was confirmed in cells aspirated from skin infiltrates at Richter transformation.

Atypical cytological features, trisomy 12, and a progressive course of disease observed in our case are typical for CLL with each of particular Ig translocations that were concomitantly found in CLL for the first time. Similar to “double hit” lymphoma concurrent rearrangements may be relevant also in CLL.     

Prognostic significance of karyotypic abnormalities in B cell chronic lymphocytic leukemia: an update

Cytogenetic analyses by G-banding and/or Q-banding techniques of leukemic B cells were performed in 102 patients with chronic lymphocytic leukemia (CLL), including six with prolymphocytic leukemia (PLL), one with hairy cell leukemia (HCL), and one with Waldenstrom's macroglobulinemia (WM) from 1979 through 1983. Follow-up after cytogenetic study ranged from 24 to 70 months. Seventeen patients had stage 0, 10 had stage I, 31 had stage II, and 44 had stage III or IV. Adequate metaphases were obtained for karyotypic analysis in 86 (84%) of 102 patients. Of these 86 patients with adequate metaphases, 43 had normal karyotypes (50%) and 43 had abnormal karyotypes (50%), of which trisomy 12 was the most frequent. Ten patients had trisomy 12 as the sole abnormality, 14 had trisomy 12 in combination with other abnormalities, and the remaining 19 had other abnormalities without trisomy 12. Abnormal karyotypes were more frequently associated with patients with advanced stages than those with early stages of the disease. Response rate to chemotherapy was significantly higher in patients with normal karyotypes than in those with abnormal karyotypes. Of eight patients who subsequently developed Richter's syndrome, seven initially had complex karyotypic changes with or without trisomy 12. These observations suggest that the chances of development of Richter's syndrome in CLL patients with multiple chromosome changes may be much higher than in those with either simple trisomy 12 or a normal karyotype. Mean frequency of abnormal metaphases was significantly higher in patients with complex trisomy 12 in combination with other changes than in those with trisomy 12 as the sole abnormality.(ABSTRACT TRUNCATED AT 250 WORDS)     

Karyotype in myelodysplastic syndromes: Relations to morphology,clinical evolution,and survival

One hundred eighty-eight unselected consecutive patients with “de novo” myelodysplastic syndrome (MDS) were studied cytogenetically. They were subclassified as 4 refractory anemia with ringed sideroblasts (RARS), 67 refractory anemia (RA), 58 refractory anemia with excess of blasts (RAEB), 40 RAEB in transformation (RAEB-t), and 19 chronic myelomonocytic leukemia (CMML). The overall incidence of chromosome abnormalities was 69%. The RAEB and RAEB-t patients showed karyotypic changes, more often than RA and CMML (76% and 100% vs. 56% and 42%, respectively). The most frequent single anomaly was del(5)(q13-q22q33) (22 cases), followed by monosomy 7 or del 7q (11 cases), del(11) (q14q23) (8 cases), trisomy 8 (4 cases). Complex karyotypes (defined by the presence of three or more structural or numerical abnormalities) were detected in 33 patients. With regard to the FAB classification, del (5)(q13q33) was associated with RA, and complex rearrangements with RAEB and RAEB-t. Leukemic transformation occurred in 66 patients (46%), none with a normal karyotype or del(11)(q14q23) as single abnormality. In patients carrying 5q- alone, acute evolution correlated with proximal breakpoint localization, being found in no case with del(5)(q13q33) but in three out of four cases with del(5)(q22q33). Acute leukemia (AL) progression happened in all cases with complex rearrangements and monosomy 7 or del(7q). Two of the four trisomy eight patients evolved in AL. By using the Cox proportional hazard regression analysis it was demonstrated that the karyotype abnormality was a significant predictor of leukemic transformation (P < 0.001). Patients with abnormal karyotypes without complex abnormalities had a survival (median survival 12 months) shorter than that of cases with only normal metaphases (median 83 months) (P < 0.001); patients with a mixture of normal/abnormal metaphases had a median survival of 31 months. The median survival for complex karyotypes was 7 months. Among cases with single defects, del(5)(q13q33) showed the best survival (64 months), mono- somy 7 and del (7q) the worst (7 months) (P < 0.001). © 1994 Wiley-Liss, Inc.     

Molecular Cytogenetic Analysis of B-CLL Patients with Aggressive Disease

We tested a set of commercially available probes to determine the feasibility and accuracy of FISH in the detection of abnormalities in 13 patients with Chronic Lymphocytic Leukemia (CLL) with a particular aggressive clinical disease. We utilized three different probes for the 13q12-14 region, one for the centromeric region of chromosome 12, one for the P53 gene at 17p13.1 and one for 3′-5′ IGH at 14q32, covering the entire region of IGH, thus potentially allowing to detect more rearrangements. Conventional cytogenetic study showed a normal karyotype in 8/13 patients. FISH was able to detect chromosomal abnormalities in 10/13 pts (85%): +12 in 4 pts (38%); del 13q in 4 (38%); del 17p in 3 (35%); del of 5′-IGH in 1 (15%). In conclusion FISH confirmed its ability to improve the detection of cytogenetic abnormalities especially in patients with an aggressive disease.     

Dup(12)(q13-q22) and 13q14 deletion in a case of B-cell chronic lymphocytic leukemia

Cases with partial trisomy 12 have rarely been found in B-cell chronic lymphocytic leukemia (CLL). We report our clinical, cytogenetic and fluorescence in situ hybridization (FISH) findings in a CLL patient with a duplication of part of the long arm of chromosome 12 between bands q13-q22. This patient was the only case with this duplication among the 112 cases (0.9%) of CLL cytogenetically analyzed in our laboratory. FISH studies using unique-sequence specific probes for the RB-1 (retinoblastoma) gene and the D13S319 locus at the 13q14 band showed a monoallelic loss for the D13S319 locus (20% of cells) with a diploid RB-1 gene. Our case showed an atypical morphology (35% prolymphocytes), a high proliferation rate and progression of the disease, indicating that the duplication of this region may be equivalent to complete trisomy 12 in CLL patients.     

Trisomy 12 in chronic lymphocytic leukemia detected by fluorescence in situ hybridization: analysis by stage, immunophenotype, and morphology

Fluorescence in situ hybridization (FISH) with a chromosome 12 specific alpha-centromeric probe was performed on interphase cells from 183 patients with B-cell chronic lymphocytic leukemia (CLL). Twenty one cases with trisomy 12 (11.5%) were detected. The number of trisomic cells ranged from 5.5% to 76% (mean 38.5%). No correlation was found between the presence of trisomy 12 and white blood cell count, hemoglobin level, platelet count, a specific immunophenotype, clinical stage, sex, splenomegaly, or lymphadenopathy. Morphologic review of all cases with trisomy 12 showed seven (33%) with more than 10% prolymphocytes and three (14%) with CLL of mixed cell type. While trisomy 12 is the most common chromosomal abnormality in CLL, it is more frequent in morphologically atypical cases, some of which may be undergoing transformation. There was a statistically significant difference in the incidence of atypical cases between those with (47%) and without (7.6%) trisomy 12 (P < .001). It remains to be determined whether this abnormality is associated with a worse prognosis; this is currently being investigated in the context of a national therapeutic trial. The technique used is more sensitive than conventional cytogenetic analysis, which in this series failed to detect trisomy 12 in six cases. FISH allows the systematic study on a large number of patients without the need of metaphase preparations.     

Aberrant expression of T-cell-associated markers CD4 and CD7 on B-cell chronic lymphocytic leukemia

By multiparameter flow cytometry, the T-cell-associated markers CD4 and CD7 were aberrantly coexpressed on a case of B-cell chronic lymphocytic leukemia (CLL). The CLL had an immunophenotype: CD19+, CD20+, CD79b+, CD5+, CD23+, FMC7+, kappa+, CD4+, and CD7+. Molecular analysis confirmed clonal rearrangement of the immunoglobin heavy chain genes and a germline configuration of the T-cell receptor genes. Fluorescence in situ hybridization showed trisomy 12 anomaly. There was no evidence of deletion 17p (p53), 11q23 (ATM), or 13q14 or translocation t(11:14). The patent was clinically stable without treatment. Although the pathogenesis of such aberrant immunophenotype remains to be determined, the current case illustrates the phenotypic heterogeneity of CLL, and emphasizes the importance of a comprehensive diagnostic approach including clinical, morphologic, immunophenotypic, and molecular cytogenetic studies.     

Fluorescent in situ hybridization and cytogenetic studies of trisomy 12 in chronic lymphocytic leukemia

Cytogenetic studies (CG) of 475 chronic lymphocytic leukemia (CLL) cases showed trisomy 12 in 6.1% or 26% of patients with abnormal karyotypes. Fluorescence in situ hybridization (FISH) detected trisomy 12 in 35% of 117 CLL patients. Only 34.6% of cases detected by FISH were detected by CG. Twelve patients had low levels of trisomic cells (4% to 11%) relative to clonal B cells (47.5% to 86%), suggestive of clonal evolution. Untreated patients with trisomy 12 were predominantly male (P < .05) and had an increased incidence of splenomegaly (P < .03). Patients with trisomy 12 were more likely to be previously treated and had advanced Binet stage compared with those without trisomy 12. The median survival was shorter in patients with trisomy 12 (7.8 years) and patients with other chromosomal abnormalities without trisomy 12 by FISH (5.5 years) than in patients with diploid karyotypes (14.4 years). The response to fludarabine was similar to that of patients with diploid karyotypes, but there was a trend for earlier disease progression. FISH detected residual disease in all patients with trisomy 12 in complete (n = 6) or partial remission (n = 4). As few as 1 trisomic cell in 5,000 was detected by performing FISH on fluorescence-activated cell sorter-sorted cells. Trisomy 12 was absent in T cells in patients with trisomy 12. We conclude that FISH identifies trisomy 12 approximately 2.6 times more often than CG, readily identifies minimal residual disease, and predicts for a shorter median survival.     

Unique gene expression and clinical characteristics are associated with the 11q23 deletion in chronic lymphocytic leukaemia

Chromosome abnormalities influence prognosis and tumour progression in B-cell Chronic Lymphocytic Leukaemia (CLL). This study sought to determine whether these different disease subgroups were associated with unique gene expression patterns. Thirty-four cases of CLL were screened for the 11q23, 13q14, 17p13 deletions, and trisomy 12 by fluorescence in situ hybridization (FISH). Expression of 205 cell signalling and apoptosis genes were compared by cDNA array among cases with different chromosome abnormalities. A majority of the statistically differentially expressed genes were present in the 11q23 deletion group by hierarchical clustering. CDC2, a serine/threonine kinase, was overexpressed in the 11q23 deletion group (P = 0.0004) and confirmed by Taqman real-time polymerase chain reaction. Several other genes associated with cell signalling were overexpressed in the 11q23 deletion group. A strong overall correlation existed between the presence of different chromosome abnormalities and a number of prognostic factors including immunoglobulin heavy chain variable region mutation status (P = 0.011), time to treatment (P = 0.025) and lymphocyte doubling time (P = 0.034). This study confirmed the prognostic impact of chromosome abnormalities identified by FISH in CLL, particularly the 11q23 deletion and trisomy 12. In addition, the 11q23 deletion group was associated with a unique gene expression pattern involving cell signalling and apoptosis genes.     

Comparison of array comparative genomic hybridization (aCGH) to FISH and cytogenetics in prognostic evaluation of chronic lymphocytic leukemia

Introduction: High‐resolution array comparative genomic hybridization (aCGH) is a method of evaluating chromosomal alterations over the entire genome. We compared aCGH with routine cytogenetics and FISH in detecting genetic alterations in chronic lymphocytic leukemia (CLL). Methods: Array comparative genomic hybridization testing was performed on 55 cases of CLL in addition to a standard panel of FISH probes (ATM on 11q22, trisomy 12, 13q14, p53 on 17p13). The frequency of detecting abnormalities was compared, and discordant results between methodologies were compared. Results: Fifty‐five CLL cases [male to female ratio of 2.2:1 and a mean age of 71 (52–90)] were analyzed by both aCGH and FISH. This group of CLL cases showed genetic abnormalities by FISH (60%; 27/45). In contrast to FISH, aCGH detected genetic abnormalities in 82% (45/55) of CLL cases; aCGH identified genetic abnormalities not detected by FISH studies in 16% (7/45) of cases, whereas FISH identified abnormalities not detected by aCGH in only 7% (3/45) of cases. Rare recurring genetic alterations were detected by aCGH including losses in 6q, 8p, 10q, 14q32, and 18q and gains in 10q. Discussion: Our findings suggest aCGH is an effective technique for evaluating recurring genetic abnormalities in CLL and improves on standard FISH in detecting genetic abnormalities in CLL.