Expression of the matrix metalloproteinase 9 in Hodgkin's disease is independent of EBV status

Background-In vitro the Epstein-Barr virus (EBV) encoded latent membrane pr otein 1 (LIMP-1) has been shown to upregulate expression of matrix metallop roteinase 9 (MMP-9), a member of a family of zinc dependent endopeptidases that is believed to facilitate tumour invasion and metastasis by degradatio n of the extracellular matrix. Aim-To test whether the expression of MMP-9 in Hodgkin's disease correlates with EBV status and survival and to investigate whether LMP-1 expression a ffects MMP-9 concentrations in the Hodgkin's disease cell line, L428. Methods-MMP-9 expression was measured by means of immunohistochemistry in a series of Hodgkin's disease tumours and this expression was correlated wit h EBV status and survival. The influence of LMP-1 on MMP-9 expression was a lso investigated in the Hodgkin's disease cell line, L428. Results-MMP-9 expression was demonstrated in the malignant Hodgkin and Reed -Sternberg cells of all (n = 86) formalin fixed, paraffin wax embedded Hodg kin's disease tumours examined. Although the intensity of RIMP-9 immunostai ning varied between cases, there was no correlation between MMP-9 expressio n and EBV status or survival. MMP-9 expression was also detected in a varie ty of non-malignant cells, including fibroblasts. MMP-9 was detected by zym ography in the L428 and KMH2 Hodgkin's disease cell lines, whereas low or u ndetectable amounts of MMP-9 were found in the L591 Hodgkin's disease cell line. Induction of LMP-1 expression in the Hodgkin's disease cell line L428 did not result in a detectable increase in the values of MMP-9 as measured by zymography. Conclusions-These results demonstrate that MMP-9 is consistently expressed by the Hodgkin and Reed-Sternberg cells of Hodgkin's disease tumours and by the Hodgkin's disease cell lines, L428 and KMH2. However, this expression does not appear to be related either to LMP-1 values or to survival.