Lack of Expression of TUBB3 Is a Feature of Both BCL2-Positive and BCL2-Negative Follicular Lymphoma
Alberto Zamo, Francesco Erdini, Chilosi Marco. University of Verona, Verona, Italy
Background: Follicular lymphoma is characterized by aberrant BCL2 expression, a feature that is exploited for diagnostic purposes. However, a certain percentage of follicular lymphomas might be BCL2-negative by immunohistochemistry, increasing the difficulties in differentiating them from follicular hyperplasia. The expression of TUBB3 has been recently reported as negative in a small series of follicular lymphomas.
Design: We have tested a series of cases for TUBB3 expression, including 22 BCL2-positive and 23 BCL2-negative follicular lymphoma cases, and compared them with 21 reactive lymphoid tissues. First, a subjective score of TUBB3 staining was applied, followed by the application of a standardized scoring system to a large number of follicles, based on virtual slides.
Results: The subjective score for TUBB3 staining showed that it was consistently positive in reactive germinal centers (20/21 cases, 95.2%), while most follicular lymphomas were negative; in fact, only 5/23 (21.7%) BCL2-positive and 2/22 (9.1%) BCL2-negative cases showed a positive staining for TUBB3. The application of the standardized scoring system based on virtual slides demonstrated that reactive lymph nodes had a higher number of TUBB3-positive follicles both compared to BCL2-positive cases (p= 8*10-9, Student's t-test) and to BCL2-negative cases (p =3,52*10-15, Student's t-test).
Conclusions: Our data support the use of TUBB3 staining in differentiating follicular lymphoma, including BCL2-negative cases, from reactive follicular hyperplasia.
Tuesday, March 5, 2013 1:00 PM
Poster Session IV # 250, Tuesday Afternoon