[1494] Significance of P53 Immunostaining in the Diagnosis of Myelodysplastic Syndromes

Zohreh Mohammad Taheri, Payam Pournazari, Iwona Auer, Adnan Mansoor, Joanne Luider, Masoud Torbatian, Meer-Taher Shabani-Rad. University of Calgary/Calgary Laboratory Services, Calgary, Canada; National Research Institute of Tuberculosis and Lung Disease, Tehran, Islamic Republic of Iran

Background: Myelodysplastic syndrome (MDS) is one of the challenging hematological disorder from diagnostic and treatment aspects. Studies have shown that apoptotic pathway, DNA hypermethylation and P53 mutation are the major underlying pathophysiology in the development of myelodysplastic disorders.
Aim:To study if p53 immunoreactivity could help differentiating MDS from secondary non- clonal dysplasia.
Design: This is a cross sectional study, performed on bone marrow specimens of patients with the clinical diagnosis of MDS (2008-2009). Four groups of cases were selected: AML-MDS, MDS with or without clonal cytogenetic abnormality, Borderline dysplastic, and Non-dysplastic/reactive cases. All bone marrow cases were stained for P53, CD34 and CD117 to assess the expression of P53, blasts count and vascular density. In addition, the H&E slides were reviewed for the presence of morphological dysplastic features and ALIP (Abnormal localization of immature precursor cells).
Results: Total of 53 cases were included on the study: AML-MDS (8 cases), MDS (24 cases), borderline dysplasia (11 cases) and Normal/reactive (10 cases). The complete immunohistochemical data was available for 19 MDS patients. All AML-MDS (8/8 (100%), 16 out of 24 MDS (67%), 5 out 11(45%) Borderline dysplasia cases showed nuclear expression of P53. None of Normal/reactive cases were positive for P53. Blasts count of more than 3% and vascular density (>20 vessel per LPF) were considered as abnormal finding. Presence of increased blasts/vascular density or ALIP was significant only in association with P53 expression (<0.05).
Conclusions: P53 is a helpful marker in the distinction of neoplastic myelodysplasia from normal/ reactive conditions. There is also strong correlation between p53 expression and increased blast count, vascular density and presence of ALIP in all groups. Expression of P53 in borderline dysplastic cases may be used as an indicator of myelodysplastic syndrome. Our study suggests that expression of P53 immunsatining adjunct with other findings is helpful in the diagnosis of MDS patients.
Category: Hematopathology

Tuesday, March 20, 2012 9:30 AM

Poster Session III # 233, Tuesday Morning

 

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