C-myc and tumour suppressor gene product expression in developing and term human trophoblast.
Proliferation and differentiation of villous trophoblast during placental development, from an early stage to full-term, were investigated in routinely fixed and processed tissues, by means of the immunocytochemical localization of the cell cycle-related proto-oncogene c-myc and the p53 and retinoblastoma susceptibility (Rb) tumour-suppressor gene products. The proliferative activity of the trophoblast was determined using an antibody against proliferating cell nuclear antigen (PCNA) which stains all proliferating cells in paraffin-embedded tissues. Diffuse nuclear immunoreactivity for PCNA, c-myc and Rb gene products was a consistent finding in early cytotrophoblast; c-myc product expression was also detectable in both layers of mid-gestation trophoblast. Only scattered cytotrophoblastic nuclei of early gestational placenta displayed immunostaining for p53 gene product. In full-term placenta c-myc expression was undetectable while Rb gene product and PCNA immunoreactivity declined markedly. These results indicate that the expression of the above genes is spatio-temporally regulated during placental development. A potential involvement of the oncosuppressor gene products p53 and Rb in the control of trophoblastic proliferation and of c-myc in the control of both the proliferative and differentiation pathways of trophoblastic cells is suggested.
Roncalli
M
M
II Department of Pathology, University of Milan, School of Medicine, Italy.
Bulfamante
G
G
Viale
G
G
Springall
D R
DR
Alfano
R
R
Comi
A
A
Maggioni
M
M
Polak
J M
JM
Coggi
G
G
D002455:Cell Division; D005260:Female; D015870:Gene Expression; D016161:Genes, Retinoblastoma; D016147:Genes, Tumor Suppressor; D016259:Genes, myc; D016158:Genes, p53; D006801:Humans; D007150:Immunohistochemistry; D011247:Pregnancy; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000378:metabolism; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C000715470:MAS1 protein, human; D018809:Proliferating Cell Nuclear Antigen; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53