A study involving pediatric patients with acute lymphoblastic leukemia (ALL) indicated that expression of Bax and Bcl-2 proteins, and the ratio of Bax/Bcl-2 proteins expressed, in patients at the time of diagnosis was not related to survival in this population. Results of the study were reported in the Asian Pacific Journal of Cancer Prevention.
Bcl-2 is an antiapoptotic protein, the overexpression of which limits apoptosis, while Bax protein has a proapoptotic role, the study investigators explained in their report. The ratio of Bax/Bcl-2 proteins can reflect a balance between proapoptotic and antiapoptotic processes and is relevant to outcomes of treatment with chemotherapy in patients with pediatric ALL, the researchers also explained.
The study was a prospective, observational analysis based at the Dr Soetomo General Academic Hospital in Surabaya, Indonesia. In this study, the researchers evaluated expression of Bax and Bcl-2 proteins from bone marrow aspirate samples obtained from pediatric patients with newly diagnosed ALL. Flow cytometry was used for quantifying expression of these proteins, which were collected from patients prior to and following induction chemotherapy. Study outcomes were survival and remission rate, which were evaluated in the context of Bax and Bcl-2 expression levels and with respect to the Bax/Bcl-2 expression ratio.
There were 17 patients with pediatric ALL who were included in the analysis. Diagnostic characteristics in this population included the L1 classification in 94% of patients, with 76% of all patients having B-cell ALL and 24% having T-cell ALL. A total of 11 patients were alive at the time of reporting, with 6 patients having died.
Prior to starting chemotherapy, the mean expression levels of Bax and Bcl-2 proteins, and Bax/Bcl-2 ratio, did not significantly differ among patients based on survival outcomes. All patients who completed induction entered remission, and the expression levels of Bax and Bcl-2 did not show significant differences prior to and after chemotherapy. However, the ratio of Bax/Bcl-2 expression levels rose from 1.74 (SD, 1.846) to a level of 6.17 (SD, 4.139) following the induction phase of chemotherapy, which was a significant difference (P =.021).
The study investigators concluded that Bax and Bcl-2 expression levels at the time of diagnosis with pediatric ALL did not show relationships to survival outcomes with induction chemotherapy. However, patients who experienced remission with induction chemotherapy showed an increase in the Bax/Bcl-2 protein expression ratio. “Proapoptotic protein was more dominant than antiapoptotic proteins in pediatric ALL, who achieved complete remission,” the study investigators wrote in their report.
Cahyadi A, Ugrasena IDG, Andarsini MR, Larasati MCS, Aryati A, Arumsari DK. Relationship between Bax and Bcl-2 protein expression and outcome of induction phase chemotherapy in pediatric acute lymphoblastic leukemia. Asian Pac J Cancer Prev. 2022;23(5):1679-1685. doi:10.31557/APJCP.2022.23.5.1679