Abstract B005: Evaluation of TP53 expression in pediatric b-cell acute lymphoblastic leukemia and its correlations with clinicopathological profiles

Abstract Evaluation Of TP53 Expression in Pediatric B- Cell Acute Lymphoblastic Leukemia And Its Correlation With Clinicopathological Profiles Authors: Hasib Tk, Parminder Kaur, Prateek Bhatia, Amita Trehan, Minu SinghAffiliation: Advanced pediatric Centre, Postgraduate Institute of Medical Education and Research (PGIMER) , Chandigarh , India. Background: TP53 is a tumor suppressor gene which impacts tumor progression and prognosis in various cancers. TP53 isoforms regulate key processes like cell cycle arrest, apoptosis, and DNA repair. Elevated TP53 expression in B-cell ALL correlates with poor outcomes, making it a potential prognostic marker and therapeutic target. This study aimed at to evaluate the expression of TP53 isoforms and its correlation with clinicopathological profiles in pediatric B-cell ALL patients. Materials and methods: One hundred pediatric B-cell ALL patients (≤12 years) and 20 age matched healthy controls were enrolled for this study. Expression of TP53 full-length and isoform Delta40TP53, Delta133TP53, TP53Beta expressions was checked using qRT-PCR. Fold change was calculated using 2- DDCt method. The expression of isoforms was correlated with various clinical parameters such as risk stratification, blast count, molecular cytogenetics etc. Results: The median age of the patients was 5 years with male: female ratio of 1.2:1. 52% patients had high expression of TP53 full gene expression with the maximum fold change of 9.99-fold. Isoform Delta40TP53, Delta133TP53 and TP53Beta was overexpressed in 17%, 53% and 6% of the patients respectively. Delta133TP53 showed significant association with presence of ETV6::RUNX1 (p=0.047) which is associated with standard risk. The presence of KMT2A::AF4 which is linked with poor prognosis was also associated with TP53Beta expression (p=0.043). However, we could not find significant association between expression of TP53 isoforms and other clinical parameters such as age, gender, TLC, MRD, or progressive disease etc. in pediatric ALL patients. Conclusions: Our study has shown that the expression of full length TP53 and its isoforms is dysregulated in Pediatric B-ALL patients. These findings suggest that Delta133TP53 could be further explored as a potential biomarker for standard risk, whileTP53Beta might serve as an indicator of poor risk in ALL, warranting further investigation in larger cohorts. Citation Format: HASIB THONDIKODAN, AMITA TREHAN, PRATEEK BHATIA, PARMINDER KAUR, MINU SINGH. Evaluation of TP53 expression in pediatric b-cell acute lymphoblastic leukemia and its correlations with clinicopathological profiles [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Discovery and Innovation in Pediatric Cancer— From Biology to Breakthrough Therapies; 2025 Sep 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2025;85(18_Suppl_2):Abstract nr B005.