Met protein encoded by MET oncogene is the high affinity receptor for hepatocyte growth factor (HGF)/scatter factor (SF). HGF/SF has to be cleaved in its heterodimeric form by the urokinase-type plasminogen activator (uPA) to become active as a ligand for Met receptor. The expression of Met protein and of the high affinity receptor for uPA. (uPA-R) was investigated in 39 samples of papillary carcinoma using immunohistochemistry. Reactivity for Met protein was present in 33 of 34 tumours, mostly with a diffuse pattern of staining. Reactivity for uPA-R was present in 78 per cent of papillary tumours and exhibited a pattern of staining similar to that of Met protein. Staining for uPA-R was present in 23 of 25 cases (92 per cent) of papillary carcinoma with prominent sclerosis, and in only 1 of 7 eases (14 per cent) without sclerosis. Peritumoural normal thyroid, follicular adenomas, and follicular carcinomas were negative for Mel protein and for uPA-R. Hyperfunctioning tall thyroid cells showed weak membrane reactivity for uPA-R and for Met protein. The findings of immunohistochemistry were confirmed at the mRNA level using in situ hybridization, since the signal for uPA-R and Met RNAs was detected in most tumour cells of five cases of papillary carcinoma.
Expression of Met protein and urokinase-type plasminogen activator receptor (uPA-R) in papillary carcinoma of the thyroid / Zanetti, A.; Stoppacciaro, Antonella; Marzullo, A.; Ciabatta, M.; Fazioli, F.; Prat, M.; Comoglio, P. M.; Baroni, C. D.; Ruco, Luigi. - In: JOURNAL OF PATHOLOGY. - ISSN 0022-3417. - 186(1998), pp. 287-291. [10.1002/(SICI)1096-9896(199811)186:3<287::AID-PATH175>3.3.CO;2-O]