Role of Angiogenesis and Endothelialmesenchymal Transition in Bone Marrow Fibrosis Associated with Haematopoietic Neoplasms: A Cross-sectional Immunohistochemical Analysis

Abstract

Introduction: The bone marrow examination is an essential investigation in the diagnosis and management of many haematological disorders. The integration of all investigations, including peripheral blood analysis, bone marrow aspirate, and trephine biopsy findings, along with supplementary tests such as immunophenotyping, cytogenetic analysis, and molecular genetic studies, is crucial for arriving at a final diagnosis. Aim: To assess the presence of reticulin fibres in bone marrow biopsy sections in haematological malignancies, to evaluate the grade of BMF associated with haematological malignancies and to assess the role of angiogenesis using IHC markers in various haematological malignancies. Materials and Methods: A cross-sectional study was conducted in the Department of Pathology at the National Institute of Pathology, Safdarjung Hospital, New Delhi, India in 2009 for a duration of 18 months. Thirty-eight patients with a diagnosis of Acute Myeloid Leukaemia (AML), Acute Lymphoblastic Leukaemia (ALL), Chronic Myeloid Leukaemia (CML), and Chronic Lymphoproliferative Disorder (CLPD) were studied. Bone marrow biopsies were taken, fixed in 10% formalin, and decalcified in 10% Ethylene Diamine Tetraacetic Acid (EDTA). Routine paraffin embedding was performed, and serial sections of 4 μm were obtained on poly-L-lysine-coated slides for Immunohistochemistry (IHC) {Vimentin, Vascular Endothelial Growth Factor (VEGF), CD-34, Smooth Muscle Actin (SMA)}. The presence of reticulin fibres in the bone marrow biopsy sections was assessed using two special stains: Gomori’s Silver Impregnation and Masson’s Trichrome. Fibrosis was quantified according to the Baurmeister 0-4 grading system of Bone Marrow Fibrosis (BMF). Results: The results of the present study suggest that Endothelial to Mesenchymal Transition (EndMT) may play a role in the pathogenesis of BMF. Various grades of fibrosis were observed, with 15 cases (39.47%) in Grade 3, followed by 11 cases (28.95%) in Grade 2, 8 cases (21.05%) in Grade 1, and 4 cases (10.53%) in Grade 4. Conclusion: BMF was a significant finding even in the early stages of the majority of the lesions studied and was closely linked with angiogenesis. This study showed that angiogenesis plays an important role in the pathogenesis of haematological neoplasms and that VEGF is a prominent stimulus in the majority of these disorders. Additionally, this study suggests that EndMT has a possible role in the pathogenesis of BMF.

Keywords

• acute lymphoblastic leukaemia
• acute myeloid leukaemia
• chronic lymphoproliferative disorder
• chronic myeloid leukaemia
• epithelial