The association of the coexpression of c-myc, PTEN and t (14;18) detected by fluorescent in situ hybridization with high proliferation index in diffuse large B cell lymphoma

INTRODUCTION: Diffuse large B cell lymphoma (DLBCL) and Burkitt lymphoma (BL) are mature agressive B cell lymphomas that have heterogeneous clinical, morphological, immunofenotypical and cytogenetic features, and have widely different clinical course. In this study, the immunohistochemical and cytogenetic features seen in DLBCL and BL and the association between the prognosis are studied. Also the characteristics that can be used to differentiate DLBCL and BL is defined.
METHODS: Totally 56 cases (45 DLBCL and 11 BL), which were diagnosed in Gazi University, Medical School, Department of Pathology between 2000 and 2007 were included to study. Bcl-2, bcl-6, CD10, MUM-1 and Ki-67 antibodies were performed immunohistochemically and c-myc amplification, PTEN deletion and t(14;18) translocation was evaluated by fluorescent in situ hybridization.
RESULTS: The expression of bcl-2, bcl-6 and CD 10 were 55.6%, 35.6% and 25.8% respectively in DLBCL cases. In the cases of BL, all the cases were bcl-2 negative, bcl-6 and CD 10 positive. While the proliferation index of Ki-67 were 63.2% in DLBCL, it was 97.2% in BL (p=0.001). The ratio of c-myc amplification was 80% in BL and 43.7% in DLBCL (p<0.05). The ratio of t(14;18) translocation and PTEN deletion was 7.7% and 26.7% in DLBCL, while it was 20% and 9.1% in BL (p>0.05).
DISCUSSION AND CONCLUSION: The usage of immunohistochemical panel, including CD 10, bcl-6, bcl-2 and Ki-67 to differentiate between DLBCL and BL is absolutely beneficial. Also Ki-67 proliferation index higher than 95% is helpful for the diagnosis of BL. Altough c-myc amplification is highly detected in BL cases, it can be seen in DLBCL slightly. No statistically significant association was detected in t(14;18) and PTEN deletion between the distinction of DLBCL and BL.

Diffüz Büyük B hücreli LenfomalardaFluoresan insituHibridizasyon yöntemi ile c-myc, PTEN ve t (14;18) koekspresyonlarýnýn yüksek proliferatifindeks ile iliþkisi

GÝRÝÞ ve AMAÇ: Diffüz büyük B-hücreli lenfoma (DBBHL) ve Burkitt lenfoma (BL), klinik, morfolojik, immünfenotipik ve sitogenetik özellikleri açýsýndan heterojen özellik gösteren matür agresif B hücreli lenfomalardýr ve oldukça deðiþken klinik seyir gösterirler. Bu çalýþmada DBBHL ve BL’da görülen immünhistokimyasal ve sitogenetik özellikler ve bunlarýn prognoz ile iliþkileri araþtýrýlmýþ ve DBBHL ile BL ayrýmýnda kullanýlabilecek özellikler tanýmlanmýþtýr.
YÖNTEM ve GEREÇLER: Çalýþmaya Gazi Üniversitesi Týp Fakültesi Patoloji Ana bilim dalýnda 2000-2007 yýllarý arasýnda taný alan 45 DBBHL ve 11 BL olmak üzere toplam 56 olgu dahil edildi. Olgulara immünhistokimyasal olarak bcl-2, bcl-6, CD10, MUM-1 ve Ki-67 antikorlarý uygulandý ve fluoresan in situ hibridizasyon yöntemi ile c-myc amplifikasyonu, PTEN delesyonu ve t(14;18) translokasyonu deðerlendirildi.
BULGULAR: DBBHL olgularýnda bcl-2, bcl-6 ve CD 10 ekspresyonu sýrasýyla %55.6, %35.6 ve %25.8 oranýnda olup, BL olgularýnýn ise tümü bcl-2 negatif olup, bcl-6 ve CD 10 pozitif saptandý. Ki-67 proliferasyon indeksi ise DBBHL’da ortalama %63.2 iken, BL’da ortalama %97.2’dir (p=0.001). BL olgularýnda c-myc amplifikasyonu %80 oranýnda görülmüþ olup, DBBHL’da %43.7 oranýndadýr (p<0.05). t (14;18) ve PTEN delesyonu, DBBHL’da sýrasýyla %7.7 ve %26.7 iken, BL’da %20 ve % 9.1 oranýnda görülmüþtür (p>0.05).
TARTIÞMA ve SONUÇ: DBBHL ile BL ayrýmýnda immünhistokimyasal olarak CD10, Bcl-6, Bcl-2 ve Ki-67 panelinin uygulanmasý yararlý bir yöntemdir. Ki-67 proliferasyon indeksinin %95’in üzerinde olmasý da BL tanýsý için oldukça faydalýdýr. C-myc amplifikasyonu özellikle BL olgularýnda yüksek oranda saptanmakla birlikte, DBBHL olgularýnda da düþük oranda da olsa görülebilir. DBBHL ve BL ayýrýmýnda t(14,18) ve PTEN delesyonu açýsýndan anlamlý fark saptanmamýþtýr.