Relevance of IgVH Gene Somatic Hypermutation and Interphase Cytogenetics in Lymphomatous Presentation of CLL/SLL

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BlankRelevance of IgVH Gene Somatic Hypermutation and Interphase Cytogenetics in

Lymphomatous Presentation of Chronic Lymphocytic Leukemia/Small Lymphocytic

Lymphoma

1.. Cecilia C.S. Yeung, MD cyeung@...

1.. Washington University

1.. L.E. Powers

1.. Washington University

1.. Friederike Kreisel

1.. Washington University

1.. L. Frater

1.. Washington University

1.. Barbara A. Zehnbauer

1.. Centers for Disease Control and Prevention

1.. Burack

1.. University of Rochester

1.. Anjum Hassan

1.. Washington University

Abstract

Background. Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma

(SLL) are regarded as the same entity, with SLL restricted to tissue cases

featuring no leukemic phase. In this study, the authors evaluate a group of SLL

cases for cytogenetic abnormalities and IgVH gene mutational status to illicit

differences between CLL and SLL. Design. IgVH gene polymerase chain reaction

amplification and subsequent sequencing were preformed on formalin-fixed,

paraffin-embedded archival tissue of 44 patients (SLL n = 34 or CLL n = 10).

Cytogenetic data, CD38, and ZAP-70 expression were also evaluated for these

cases. Results. The data indicate that 9/34 (26%) SLL cases have somatic

hypermutation >2%, which is less than the CLL group where 40% were mutated

(4/10). Cytogenetic abnormalities were seen in 58% of the SLL cases with many

showing abnormalities associated with favorable to intermediate prognosis.

Conclusion. The authors’ attempt to compare CLL with SLL with regards to

cytogenetic and IgVH mutational status shows no statistically significant

difference.