Leukemic involvement is a common feature in mantle cell lymphoma

Area of Science:

• Hematology
• Oncology
• Genetics

Background:

• Peripheral blood involvement in mantle cell lymphoma (MCL) has a wide reported incidence (13-77%).
• Understanding the prevalence and significance of leukemic involvement is crucial for MCL patient management.

Purpose of the Study:

• To determine the prevalence of leukemic expression in MCL patients.
• To analyze the biologic and clinical significance of leukemic involvement in MCL.

Main Methods:

• Leukemic expression assessed by conventional morphology and flow cytometry (FC) in 48 MCL patients.
• Comparative genomic hybridization (CGH) performed in 27 patients to detect chromosomal imbalances.
• Lymphocyte counts analyzed to identify correlations with clinical and genetic factors.

Main Results:

• Flow cytometry (FC) detected leukemic expression in 92% of MCL patients at diagnosis.
• Morphologically apparent leukemic involvement was observed in 17% of patients.
• Lymphocytosis (> or =5 x 10(9)/L) was present in 52% of cases and associated with gains of 3q, losses of 10p, lower response rates, and shorter survival.

Conclusions:

• Leukemic expression is highly frequent in MCL at diagnosis, as detected by FC.
• Morphologically apparent leukemic involvement did not correlate with specific chromosomal alterations via CGH.
• Lymphocytosis (> or =5 x 10(9)/L) in MCL is linked to distinct genetic abnormalities and a poorer clinical outcome.