Kodali D, Rawal A, Ninan MJ, Patel MR, Mesa H, Knapp D, Schnitzer B, Kratzke RA, Gupta P. Expression and phosphorylation of eukaryotic translation initiation factor 4E binding protein 1 in B-cell lymphomas and reactive lymphoid tissues.
Arch Pathol Lab Med 2011;
135:365-71. [PMID:
21366462 DOI:
10.5858/2009-0759-oa.1]
[Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CONTEXT
Cap-mediated messenger RNA translation controlled by the eukaryotic initiation factor 4F (eIF-4F) complex plays a key role in human cancer. eIF-4F activity is controlled by a repressor binding protein (4E-BP1), which promotes translation when phosphorylated.
OBJECTIVE
To examine the level of expression and phosphorylation of 4E-BP1 in various subtypes of B-cell lymphoma and reactive lymphoid tissues.
DESIGN
Archival formalin-fixed, paraffin-embedded B-cell lymphoma samples and reactive lymphoid tissues were immunostained and examined for expression of 4E-BP1 and phosphorylated 4E-BP1. Expression of components of the eIF-4F complex and unphosphorylated and phosphorylated 4E-BP1 was confirmed using Western immunoblotting on lysates of frozen lymphoma samples and reactive tissues.
RESULTS
Immunohistochemical analysis demonstrated weak to undetectable 4E-BP1 staining within benign, reactive germinal centers (N = 10). In contrast, 4E-BP1 was consistently expressed (moderate to strong staining) in 98% of various subtypes of mature B-cell lymphoma (N = 50). 4E-BP1 expression was also demonstrable in all 4 lymph nodes with in situ or partial involvement by follicular lymphoma and in all 12 cases of BCL2-negative lymphoma. The level of phosphorylation of 4E-BP1 in lymphomas, evaluated by immunohistochemistry, was heterogeneous.
CONCLUSIONS
The immunohistochemical expression pattern of 4E-BP1 exhibits regional and cellular specificity in reactive lymphoid tissues and may offer a diagnostic tool for distinguishing reactive follicles from neoplastic B-cell proliferations.
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