C-MYC, C-ERBB-2, C-FMS AND BCL-2 ONCOPROTEINS - EXPRESSION IN NORMAL PLACENTA, PARTIAL AND COMPLETE MOLE, AND CHORIOCARCINOMA

OBJECTIVE: To determine the expression of bcl-2, c-myc, c-fms and c-er bB-2 oncoproteins in normal placentas, partial and complete hydatidifo rm moles, and choriocarcinomas and to examine the possible presence of mutations in the K-ras gene in complete moles and choriocarcinomas. S TUDY DESIGN: The expression of the above oncoproteins was determined i mmunohistochemically by specific antibodies for these proteins on form alin-fixed paraffin sections of 18 normal placentas, 17 partial moles, 25 complete moles and 11 choriocarcinomas. This was followed by polym erase chain reaction analysis (Exons 12 and 13) of K-ras gene for poss ible mutations in complete moles and choriocarcinomas. RESULTS: Expres sion of c-fms oncoprotein appeared confined to the cytoplasm of syncyt iotrophoblastic cells. The c-fins protein staining intensity of the sy ncytiotrophoblastic layer showed no significant difference among the f our gestational tissues. c-erbB-2 antibody expression was confined to the cellular membrane of the extravillous trophoblast. When compared w ith normal placenta or partial mole, the expression of c-erbB-2 protei n was significantly stronger in complete male (P < .0001 and P < .0001 , respectively) and choriocarcinoma (P < .0001 and P < .0001, respecti vely). Expression of bcl-2 protein was significantly stronger in the s yncytiotrophoblast in complete mole and choriocarcinoma as compared to both normal placenta and partial mole (P < .0001 and P < .0001, respe ctively). Staining of c-myc of the syncytiotrophoblastic layer was sig nificantly stronger it placenta, complete mole and choriocarcinoma tha n in partial mole (P < .0001, P < .0001 and P < .0001, respectively). Mutation in Kras gene was not found in any of the 22 complete moles or 11 choriocarcinomas examined. CONCLUSION: Our data suggest that c-myc , c-erbB-2, c-fms and bcl-2 oncoproteins may be important in the patho genesis of complete mote and choriocarcinoma. However, while both comp lete male and choriocarcinoma were characterized by overexpression of c-myc, c-erbB-2 and bcl-2, partial mole generally did Mot strongly exp ress these three oncoproteins.