[1439] CD30 Expression in Diffuse Large B Cell Lymphomas

Saurabh Malhotra, Olga V Danilova, Alexey V Danilov, Prabhjot Kaur, Norman B Levy. Geisel School of Medicine at Dartmouth, Hanover, NH; Dartmouth-Hitchcock Medical Center and Norris Cotton Cancer Center, Lebanon, NH

Background: Brentuximab vedotin is a humanized anti CD30 antibody, active in the treatment of diseases positive for CD30 expression such as Hodgkin lymphoma and anaplastic large cell lymphoma. Recently, it has been shown to be active in diseases with more variable expression of CD30 such as advanced mycosis fungoides and peripheral T cell lymphoma. The minimal level of CD30 expression necessary for activity has not been established, and is the focus of ongoing treatment protocols. Recently, a patient at our institution with chemotherapy refractory, CD30 positive plasmablastic lymphoma was treated with Brentuximab under a compassionate use protocol, and showed marked response. This suggested its utility in the treatment of diffuse large B cell lymphomas (DLBCL), but as with T cell lymphomas, the minimal level of expression necessary for activity is unknown. There is paucity of recent literature on CD30 expression in DLBCL. We assessed without any prior definition of “positivity” the expression of CD30 in DLBCL and also correlated it with other prognostic indicators.
Design: A tissue microarray (TMA), containing 86 cases of DLBCL, diagnosed between 1999 and 2006, were analyzed by immunohistochemistry (IHC) for CD30. Staining was graded based on Allred scoring system:

Grading based on proportion of positive tumor cells.
Percentage of tumor cells positive0%1%10%30%70%100%
Grade012345


Intensity was graded as Weak-1, Intermediate-2, Strong-3. Total score was calculated by adding proportion and intensity grades (Range: 0, 2-8). The results were correlated with DLBCL subtype (germinal vs. non-germinal), International Prognostic Index (IPI) score, and overall survival at a total cutoff score “3”. Chi-square test (χ2) was used for analysis.
Results: CD30 expression at different total scores was:

Percentage of positive cases at different total scores
Total ScorePercentage of positive cases
258%
347%
433%
523%
611%
78%
83%


63% non-GC (26/41) and 29% of GC (11/38) showed CD30 expression at a cut off score “3” (Chi2=9.409, P=0.002). CD30 expression did not correlate with survival or IPI.
Conclusions: CD30 expression was seen in 58% cases (at least 1% or more positive tumor cells) and 34% of cases had 10% or higher positive tumor cells. CD30 expression showed positive correlation with the non germinal phenotype. Brentuximab may therefore, have a role in the treatment of DLBCL.
Category: Hematopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 206, Monday Afternoon

 

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