Expression of c-Met correlates with grade of malignancy in human astrocytic tumours: an immunohistochemical study

Aims: Recent studies suggest the involvement of hepatocyte growth factor/scatter factor (HGF/SF) in glioma cell invasion and tumour progression, We investigated the distribution and rate of tumour cells that express c-Met protein, which is the cell-surface receptor for HGF/SF, in astrocytic tumours, The type of cells that express c-Met in tumour tissues was also identified, Methods and results: c-Met expression was screened immunohistochemically in a total of 43 astrocytic tumours, including 14 low-grade astrocytomas (A), 13 anaplastic astrocytomas (AA) and 16 glioblastoma multiforme (GBM). c-Met reactivity was demonstrated predominantly in the cytoplasm of tumour cells, Bizarre large tumour cells tended to stain intensely. Higher c-Met expression levels (greater than or equal to 2+, more than 25 % cells were positive) were noted in 21.4%, of (A) vs. 53.8% in (AA) and 87.5% in (GBM) (P < 0.001), indicating a dear relationship between c-Met protein staining and higher grade astrocytic tumours, Moreover, c-Met immunoreactivity was also shown in tumour micro microvasculature. reactive astrocytes, and neurones in the cortex infiltrated by glioma cells. In 85.7% of cases containing infiltrated cortex, neurones were positive vs, no neurones in non-neoplastic regions (P < 0.002). Conclusions: This evidence suggests that c-Met expression in the brain could be associated with astrocytoma progression and also reactive process. Immunohistochemical determination of c-Met-expressing cell types helps to understand possible roles of c-Met in tumour tissues.