Mantle cell lymphomas are positive for all of the following except-
**Core Concept**
Mantle cell lymphomas (MCLs) are a type of non-Hodgkin lymphoma characterized by the overexpression of cyclin D1, resulting from the t(11;14)(q13;q32) translocation. This genetic abnormality leads to the deregulation of cell cycle progression.
**Why the Correct Answer is Right**
MCLs are typically positive for B-cell markers such as CD19, CD20, and CD22, reflecting their B-cell origin. Additionally, they often express cyclin D1, which is a key driver of their pathogenesis. The correct answer is positive for these markers.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because mantle cell lymphomas are not typically positive for CD5, which is more commonly expressed in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL).
**Option B:** This option is incorrect because mantle cell lymphomas can express CD23, although it is not a reliable marker for this diagnosis.
**Option C:** This option is incorrect because mantle cell lymphomas are not typically positive for T-cell markers such as CD3, CD4, or CD8.
**Clinical Pearl / High-Yield Fact**
Mantle cell lymphomas often present with lymphadenopathy, hepatosplenomegaly, and bone marrow involvement, and may be associated with a poor prognosis. The t(11;14)(q13;q32) translocation is a characteristic feature of this disease.
**Correct Answer:** A.