quotCHANGES IN THE METHYLATION PATTERN OF P53 GENE PROMOTER IN THE MEGALOBLASTIC BONE MARROWquot

Abstract

The objectives is Screening andselection of at least 50 control subjects and50 megaloblasticcases. Estimation of VitaminB12 andFolate (VB9) levels in control non-megaloblasticanemia samples andmegaloblastic anemia cases andcorrelate withhematological parameters andclinical diagnosis.Measure the expression of p53 in control non-megaloblastic anemia samples andmegaloblastic anemia cases using IHC andcorrelate with VB12 andVB9 levels.Assess whether methylation of p53 promoter has an impact on its expression using methylation specific PCR (MS-PCR)Correlate the levels of p53 expression with levels of apoptosis in megaloblasticanemia (Vit B12,B9) andcontrol non-megaloblastic samples.Levels of serum VB9, VB12 andhomocysteine in 50 patients sufferingfrom MBA were compared with 50 non-megaloblastic anemia control subjects. Out of 50 objects, 40 (80%) and44 (88%) subjects had very lowVB12 andVB9 levels respectively. Only 2 (4%) and12 (24%) nonmegaloblasticanemia controls, had low VB12 andVB9respectively, the homocysteine levels werehigh in 80% cases. But, only 20% non-megaloblastic controls exhibited highhomocysteine in plasma. Immunohistochemical analysis for p53 expression showeda high level of expression in MBA,low-expression in control subjects. Correlation studies comparing the VB12 andVB9 levels with p53expression concludes high p53 levels in patients suffering from VB12 andVB9 deficiency induced MBA compared to control subjects. The expression of p53 is in good correlation with the levels of apoptosis. No changes in the methylation status of the p53 promoter region. Tumor protein-53 (TP53) is the key transcription factor expressedheavily in the bone marrow biopsies of patients suffering from VB12 andVB9deficiency induced MBA but not in control subjects. Elevated p53-expression induced apoptosis could be one of the reasons for megaloblasts shorter survival timecompared to normal non-megaloblastic anemia controls. Hence, p53 expressioncould be used as a surrogate marker for confirming the VB9 andVB12 induced MBA. newline