Increased expression of platelet derived growth factor receptor β on trephine biopsies correlates with advanced myeloma.

PURPOSE: Multiple myeloma (MM), a major cause of cancer mortality, is considered the second most frequent haematological malignancy in Europe. Angiogenesis is a multifactorial process that drives the tumorigenesis in solid tumors and in MM. The platelet derived growth factor (PDGF) receptors are cell surface tyrosine kinase receptors and play an important role in angiogenesis, cancer cell proliferation and dissemination. Few studies have been conducted regarding the expression of PDGF receptors and the correlation with clinical-pathological parameters and prognosis in MM. The purpose of our study was to evaluate, for the first time, in a large cohort of newly-diagnosed MM (NDMM) patients, the expression of PDGF receptor α and β (PDGFR α, β) in bone marrow trephine biopsies and investigate the association of PDGFR α, PDGFR β with angiogenesis in the bone marrow, assessed by bone marrow microvessel density (MVD), clinical characteristics and prognosis.

METHODS: In this retrospective study, we assessed the relation of PDGFR α and PDGFR β immunohistochemical expression with MVD in formalin-fixed paraffin-embedded bone marrow sections from 120 NDMM patients. The immunoreactivity of PDGFR α and β was examined on the basis of positive plasma cells (PCs) with specific cut off values.

RESULTS: PDGFRα and PDGFRβ were frequently expressed on malignant PCs. We found that increased PDGFRβ expression was strongly associated with advanced disease and adverse prognosis. The expression of PDGFRα and MDV were not correlated with specific features.

CONCLUSION: This analysis showed highly expressed PDGFRα and β PCs of NDMM patients and indicated that high PDGFRβ expression at diagnosis was associated with advanced-stage disease.