EXPRESSION OF C-MET CORRELATES WITH GRADE OF MALIGNANCY IN HUMAN ASTROCYTIC TUMORS - AN IMMUNOHISTOCHEMICAL STUDY

Aims: Recent studies suggest tile involvement of hepatocyte growth fac tor/scatter factor (HGF/SF) in glioma cell invasion and tumour progres sion, We investigated the distribution and rate of tumour cells that e xpress c-Met protein, which is the cell-surface receptor for HGF/SF, i n astrocytic tumours, The type of cells that express c-Met in tumour t issues was also identified, Methods and results: c-Met expression was screened immunohistochemically in a total of 43 astrocytic tumours, in cluding 14 low-grade astrocytomas (A), 13 anaplastic astrocytomas (AA) and 16 glioblastoma multiforme (GBM). c-Met reactivity was demonstrat ed predominantly in the cytoplasm of tumour cells, Bizarre large tumou r cells tended to stain intensely. Higher c-Met expression levels (gre ater than or equal to 2+, more than 25 % cells were positive) were not ed 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 high er grade astrocytic tumours, Moreover, c-Met immunoreactivity was also shown in tumour micro microvasculature. reactive astrocytes, and neur ones in the cortex infiltrated by glioma cells. In 85.7% of cases cont aining infiltrated cortex, neurones were positive vs, no neurones in n on-neoplastic regions (P < 0.002). Conclusions: This evidence suggests that c-Met expression in the brain could be associated with astrocyto ma progression and also reactive process. Immunohistochemical determin ation of c-Met-expressing cell types helps to understand possible role s of c-Met in tumour tissues.