Expression of Met protein and urokinase-type plasminogen activator receptor (uPA-R) in papillary carcinoma of the thyroid.
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 cases (14 per cent) without sclerosis. Peritumoural normal thyroid, follicular adenomas, and follicular carcinomas were negative for Met 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.
Zanetti
A
A
Dipartimento di Medicina Sperimentale e Patologia, Università La Sapienza, Roma, Italy.
Stoppacciaro
A
A
Marzullo
A
A
Ciabatta
M
M
Fazioli
F
F
Prat
M
M
Comoglio
P M
PM
Baroni
C D
CD
Ruco
L P
LP
D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000737:chemistry* / Q000556:secondary*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D010960:Plasminogen Activators / Q000032:analysis*; D019859:Proto-Oncogene Proteins c-met / Q000032:analysis*; D011956:Receptors, Cell Surface / Q000032:analysis*; D055293:Receptors, Urokinase Plasminogen Activator; D013964:Thyroid Neoplasms / Q000737:chemistry*
C524898:PLAUR protein, human; D011956:Receptors, Cell Surface; D055293:Receptors, Urokinase Plasminogen Activator; D019859:Proto-Oncogene Proteins c-met; D010960:Plasminogen Activators