Bax Gene Polymorphism in Childhood Acute Lymphoblastic Leukemia and Evaluation of Apoptosis with Conventional Dose-Prednisolone Treatment

INTRODUCTION: It is known that the agents used in cancer treatment increase apoptosis and cause cell death. In this study, the importance of G-248A nucleotide polymorphism affecting the BAX gene expression and apoptosis in children with acute lymphoblastic leukemia (ALL) was investigated in the risk classification and the evaluation of the treatment response.
METHODS: Apoptosis index was performed by Annexin V- FITC kit for bone marrow aspiration samples of 25 newly-diagnosed (0-11) years old ALL patients on 0th, 3rd and 8th day. Bax gene polymorphism was studied on blood samples of 60 ALL patients and 96 healthy control group, and DNA isolation was studied by FUJÝ QuickGene 810 automatic nucleic acid purification system.
RESULTS: The mean age of the patients was 4.9, and %28 had a standard risk, %44 had a moderate risk, %28 had high risk. A significant difference and a positive correlation were found between the spontaneous apoptosis index (AI) and the 3rd day AI (18.3±13.7, 19.4±12.7 p= 0,007 r= +0.548). The 8th day AI was found to be significantly higher in patients with poor early steroid response (p<0.05). Apoptosis index; was significantly high on 0th, 3rd and 8th day for PreB ALL cases. 84% of the patients were found to have CD 10 positivity and in cases with intense CD10 expression, AI was significantly higher on the third day (p <0.05). It was determined that the BAX gene polymorphism did not differ in the patient and control groups.
DISCUSSION AND CONCLUSION: In the present study, conventional dose prednisolone was thought to induce apoptosis significantly, and the 8th day AI elevation was associated with blast load in patients with poor early steroid response.It was concluded that the significant increase in apoptosis ratio in cases with intense CD10 expression was a valuable marker in terms of prognosis in Pre B ALL.It was considered necessary to evaluate the effect of BAX gene polymorphism on the pathogenesis, clinical course and prognosis of ALL with more cases, and to investigate other proteins that play a role in the apoptosis pathway.

Çocukluk Çaði Akut Lenfoblastik Lösemilerinde Bax Gen Polimorfizmi ve Konvansiyonel Doz Prednisolon Tedavisi ile Apoptozun Deðerlendirilmesi

GÝRÝÞ ve AMAÇ: Kanser tedavisinde kullanýlan ajanlarýn apoptozu arttýrarak hücre ölümüne yol açtýðý bilinmektedir. Bu çalýþmada akut lenfoblastik lösemili (ALL) çocuklarda BAX gen ekspresyonunu etkileyen G-248A nukleotid polimorfizminin ve apoptozun risk sýnýflandýrýlmasýnda ve tedavi yanýtýnýn deðerlendirilmesindeki önemi araþtýrýldý.
YÖNTEM ve GEREÇLER: Çalýþmada apoptoz indeksi (0-11) yaþ aralýðýndaki, yeni taný 25 ALL’ li hastanýn kemik iliði aspirasyon örneklerinde 0, 3 ve 8.gün Annexin V- FITC kiti kullanýlarak yapýldý. Bax gen polimorfizmi 60 ALL 'li hasta ve 96 saðlýklý kontrol grubunun kan örneklerinde DNA izolasyonu FUJÝ QuickGene 810 otomatik nükleik asit pürifikasyon sistemi ile çalýþýldý.
BULGULAR: Hastalarýn ortalama yaþý 4.9 olup %28' i standart risk, %44'ü orta risk, %28'i yüksek risk grubundaydý. Spontan apoptoz indeksi (AÝ) ile 3.gün AÝ arasýnda anlamlý bir fark ve pozitif korelasyon saptandý ( 18.3±13.7, 19.4±12.7 p= 0,007 r= +0.548). Erken steroid yanýtý kötü olan olgularda 8.gün AÝ anlamlý olarak yüksek gözlendi (p<0.05). Pre-B ALL olgularýnda 0.gün, 3.gün ve 8. gün AÝ anlamlý olarak yüksek bulundu (p<0.05). Hastalarýn %84’ünde CD 10 pozitifliði saptanmýþ olup CD10 ekspresyonu yoðun olan olgularda 3.gün AÝ anlamlý olarak yüksek görüldü (p<0.05). BAX gen polimorfizminin hasta ve kontrol grubunda deðiþiklik göstermediði tespit edildi.
TARTIÞMA ve SONUÇ: Çalýþmamýzda konvansiyonel doz prednisolonun apoptozu belirgin bir þekilde indüklediði ve erken steroid yanýtý kötü olan olgularda 8.gün AÝ yüksekliðinin blast yüküyle iliþkili olduðu düþünüldü. CD10 ekspresyonu yoðun olgularda apoptoz oranýndaki anlamlý artýþýn Pre B ALL’de prognoz açýsýndan deðerli olduðu kanýsýna varýldý.
BAX gen polimorfizminin ALL’nin patogenez, klinik seyir ve prognozdaki etkisinin daha fazla olgu sayýsý ile deðerlendirilmesi ve apoptoz yolaðýnda rol oynayan diðer proteinlerin de araþtýrýlmasýnýn gerekli olduðu düþünüldü.