Fluorescence in situ hybridization analysis of the PRV-1 gene in polycythemia vera: Implications for its role in diagnosis and pathogenesis

Objective In polycythemia vera (PV) there is no specific clonal marker because the molecular lesion responsible for PV is unknown. The recent demonstration that the PRV-1 gene is overexpressed in granulocytes from patients with PV provided the rationale for the current study to investigate whether PRV-1 is structurally rearranged, thus explaining its aberrant expression. Materials and Methods Fluorescence in situ hybridization was used to determine chromosomal localization of PRV-1 and to study whether the PRV1 gene is rearranged in 26 patients with PV. Results PRV-1 was localized to chromosome 19, band region q13.12-2. Structural rearrangements of PRV-1 were evaluated in bone marrow cells from 26 patients with PV: 14 with a normal karyotype and 12 with an abnormal karyotype. None of 150 metaphase cells or more than 10,000 interphase cells demonstrated PRV-1 gene deletion, amplification, or separation of the probe signal, which would indicate a PRV-1 rearrangement. Conclusion These findings are consistent with a lack of structural rearrangement of PRV-1 in patients with PV. Thus, overexpression of PRV-1 in granulocytes from patients with PV is related to mechanisms that do not involve structural genetic changes.