Burkitt&;s lymphoma is positive for-
**Question:** Burkitt's lymphoma is positive for
A. CD10
B. CD20
C. CD22
D. CD38
**Correct Answer:** D. CD38
**Core Concept:**
Burkitt's lymphoma is a rapidly progressive and highly aggressive B-cell non-Hodgkin lymphoma (NHL) characterized by chromosomal abnormalities and the presence of the translocation t(8;14)(q24;q32) involving the MYC gene and the IGK or IGH gene. It is named after the British medical student Dennis Burkitt, who first described this lymphoma in Africa in 1958.
**Why the Correct Answer is Right:**
Burkitt's lymphoma is a B-cell NHL, and CD38 is a surface marker expressed on B cells, plasma cells, and activated T cells but not on normal B cells or resting B cells. In Burkitt's lymphoma, CD38 is overexpressed on the malignant B cells, making CD38 a useful diagnostic marker for the disease. CD38 is a type II transmembrane glycoprotein that plays a role in immune response regulation, cell adhesion, and apoptosis inhibition, among other functions.
**Why Each Wrong Option is Incorrect:**
A. CD10 is expressed on both normal mature B cells and Burkitt's lymphoma cells, making it a poor marker for distinguishing between normal and malignant B cells.
B. CD20 is a B-cell marker expressed on mature B cells, activated B cells, and memory B cells but not on plasma cells or T cells. In Burkitt's lymphoma, CD20 expression is downregulated or absent due to BCL6 gene translocation, which disrupts the CD20 gene.
C. CD22 is a B-cell marker expressed on mature B cells, activated B cells, and memory B cells but not on plasma cells or T cells. In Burkitt's lymphoma, CD22 expression is not affected by the chromosomal abnormalities found in the disease, making it a poor marker for distinguishing between normal and malignant B cells.
**Clinical Pearl:**
CD38 overexpression in Burkitt's lymphoma makes it a useful diagnostic marker for the disease. However, it is essential to be familiar with the normal cell expression patterns of the listed markers to avoid misdiagnosis. Understanding the molecular basis of marker expression changes in Burkitt's lymphoma is crucial for accurate diagnosis and treatment planning.