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

Abstract

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.

Screening of the entire coding region of p53 in low grade lymphoproliferative disorders

“…Studies of the incidence of trisomy 12 in CLL have found that the application of strict classification criteria results in a lower rate of abnormality than that reported previously, and have also found this karyotypic abnormality to be more common in atypical than typical CLL. 5 In our present study, the p53 mutation rate was higher in atypical CLL (12%) than in typical CLL (4%) and this is in keeping with a higher degree of genomic instability in this subtype.…”

Comparison of flow cytometric methods for the measurement of ZAP-70 expression in a routine diagnostic laboratory

“…Peripheral blood samples [ethylenediaminetetraacetic acid (EDTA)] were collected from 33 patients between March and July 2004. Using the classification system of Howe et al. (1997), which takes into account both morphological and immunophenotypic parameters, 12 (36%) patients were typical CLL, eight (24%) were atypical, six (18%) were CLL with prolymphocytes (CLL/PL) (>10% <55%) and seven (21%) were unclassifiable.…”

In vitro chemosensitivity of chronic lymphocytic leukaemia to purine analogues – correlation with clinical course

“…All patients had a significant lymphocytosis; at the time of study the majority of the lymphocytes were malignant. Strict criteria were applied to define the diagnosis and patients were classified as typical CLL or atypical CLL according to surface immunophenotype and morphology 16 22 and response criteria were defined by the NCI-sponsored working group. 23 …”

“…In this report, strict morphological and immunophenotypic criteria have been used to define the patient population and inclusion has been restricted to CLL only. 16 A recent report suggested that atypical CLL was more likely to progress clinically than typical CLL, 17 implying that some fundamental difference exists between these two subtypes of disease. The present belief that CLL arises through a defect in the apoptotic pathway raises the question as to whether typical and atypical CLL show similar apoptotic responses, and led to the further classification of patients in this report as typical and atypical CLL.…”