USMLE (United States Medical Licensing Examination) Step 1 Practice Exam 2025 - Free USMLE Step 1 Practice Questions and Study Guide

The translocation t(14;18) is primarily associated with follicular lymphoma. This genetic alteration results in the juxtaposition of the BCL-2 gene on chromosome 18 with the immunoglobulin heavy chain locus on chromosome 14. This translocation leads to the overexpression of the BCL-2 protein, which is an anti-apoptotic factor. As a result, B cells that would normally undergo apoptosis (programmed cell death) in the germinal center after failing to successfully undergo affinity maturation are allowed to survive and accumulate, creating a population of cells that can contribute to the development of lymphoma.

In the context of follicular lymphoma, this mechanism explains the characteristics of the disease, which often presents as a slow-growing, indolent lymphoma with follicular growth patterns. The persistence of these cells due to the inhibition of apoptosis is a key factor in the pathogenesis of follicular lymphoma.

The other conditions listed, while they may have their own genetic alterations and pathways leading to lymphoma development, do not typically involve the t(14;18) translocation or the associated BCL-2 overexpression in the same way follicular lymphoma does.