Molecular Cytogenetic Profiling Reveals Similarities and Differences Between Localized Nodal and Systemic Follicular...

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Gene expression (GE) classifiers effectively distinguish localized nodal follicular lymphoma (LFL) from systemic follicular lymphoma (SFL) and have prognostic value.
• Limited data exist on genetic alterations in LFL, particularly hotspot mutations impacting pathogenesis and prognosis, contrasting with SFL.

Purpose of the Study:

• To analyze hotspot genetic alterations, including chromosomal deletions (1p, 6q, 17p) and BCL2 translocations, in LFL and SFL.
• To determine the prognostic impact of these genetic alterations on the clinical outcome of LFL patients.

Main Methods:

• Analysis of 144 LFL and 527 SFL patients from German Low Grade Lymphoma Study Group clinical trials.
• Fluorescence in situ hybridization (FISH) was used to detect deletions in chromosomes 1p, 6q, 17p, and BCL2 translocations.

Main Results:

• BCL2 translocations and 6q deletions were more frequent in SFL than LFL; 1p and 17p deletions were comparable.
• While chromosomal deletions (1p, 6q, 17p) predicted outcome in SFL, only 1p deletions retained prognostic significance in R-CHOP-treated SFL.
• No investigated genetic alterations, including BCL2 translocations, showed prognostic impact in LFL.

Conclusions:

• LFL exhibits a genetic profile partially resembling SFL, but with distinct frequencies of certain deletions and translocations.
• BCL2 translocation and 6q deletion frequencies differ between LFL and SFL, potentially contributing to their distinct genetic profiles.
• Investigated genetic alterations do not hold prognostic value for LFL patients, highlighting differences from SFL.