1. Introduction: The clinical features of neoplasia are due to capacity of tumor cells to proliferate. Neoplastic cells often have an abnormal DNA content (DNA aneuploid) in comparison to normal diploid cells. Aneuploidy is believed to reflect the numerical or structural chromosomal aberrations present in neoplastic cells [1-3]. The purpose of this investigation was to evaluate the association of DNA ploidy, S-phase and some regulatory cell cycle indicatrores (apoptotic and antiapoptotic) with survival rate, we determined the potential use of such parameters as predictive markers for childhood with acute lymphoblastic leukemia (ALL) Flow Cytometric Analysis of DNA Cell Cycle, p53, BCl2 and c-myc in Childhood with Acute Lymphoblastic Leukemia. Correlation with Patients' survival Gihan El-Hussiney Gawish *; Ahmed A. Settin**; Abdelfattah M. Attallah***; Biochemistry Dep., Faculty of Science, KSU University*; Pediatrics and Genetics Dep., Faculty of Medicine, Mansoura University**; Biotechnology Research Center, New Damietta*** Author e-mail: ggawish@ksu.edu.sa Subjects and Methods In this study we investigated DNA cycle (ploidy), apoptosis, p53, Bcl2, and c-myc by Flowcytometry in lymphocytes obtained from peripheral blood of 70 children with acute lymphoblastic leukemia before they were given chemotherapy. ALL cases were (54%) male and (46%) female The median age was 5 years (age range, 2 to 11 years). The duration of the diagnosis; and duration of remission; relapse or death were recorded during protocol therapy Result This study revealed that the number of hyperdiploid cases was 23 out of 70 cases (33%) and 47 out of 70 cases (67%) were diploid. ALL children with DNA index ≥ 0.94 showed a better overall survival compared to those with DNA index <0.94, the median of overall survival corresponding to S < 4.5% was significantly higher than the median of overall survival corresponding to S≥ 4.5%.Also, the median of overall survival has lower p53 showed higher significant than the median of OS corresponding to higher p53. Histogram showing cell cycle parameters (aneuploid and diploid) using flow cytometer FACS caliber program modfit Flowcytometric analysis of p53 expression on mononuclear cells showing histogramand dot plot of positively stained cells in relation to negative ones. Kaplan Meier curve for rates of patients with ALL categorized to DNA index. Log rank test showed p< 0.01 Kaplan Meier curve for OS rates of patients with ALL categorized to S%. Log rank test showed p<0.01 Kaplan Meier curve for rates of patients with ALL categorized to p53 levels. Log rank test showed p= 0.001 Kaplan Meier curve for rates of patients with ALL categorized to bcl2 levels. Log rank test showed p= 0.19 Discussion We found that the prognosis of children with ALL was worse when cells had an unusual number of chromosomes (aneuploid), better with a normal number (diploid), and best with exactly twice the normal number of chromosomes (teteraploid). Similarly, patients with indications of greater cell proliferation also had a warse prognosis Patients with p53-positive leukemic cells had significantly shorter survival times under chemotherapy than those with p53-negative leukemic cells [3]. We observed that median of children with ALL patients of overall survival (OS) has lower p53 showed higher significant than the median OS corresponding to higher p53. There was a strong prognostic effect on OS in related to p53 level Conclusion: Finally, we can conclude that analysis by flow cytometry is an ideal way to detect diploid & aneuploid and apoptotic & antiapoptotic markers in childhood acute lymphoblastic leukemia. It is rapid, automated and interpretable read can be obtained in most patients. We conclude that, using DNA cycle analysis and apoptosis level in addition to apoptotic promoter (p53) and apoptotic inhibitor (Bcl2 and c-Myc) of peripheral blood lymphocytes can be of help for prediction of prognosis References: 1-Moorman AV, Richards SM, Martineau M, (2003). Outcome heterogeneity in childhood high-hyperdiploid acute lymphoblastic leukemia. Blood, 102 (8): 2756-62. 2-Pinto AE, Fonseca I, Soares J, (2006). DNA flow cytrometry in solid tumors. Acta Med Port., 15(2):133-42. 3-Sainger N, Shal M, Desai A, Shukla S, (2006). Clinical significance of serum p53 antibodies in oral cancer.Tumori, 92(2):134-9