Immunohistochemical analysis of bcl-2, bax, mcl-1, and bcl-X expression in ovarian surface epithelial tumors.
Cell survival may be enhanced in tumors by the inhibition of apoptosis, which allows tumor promotors to exert their effects. The bcl-2 related genes have been shown to contribute to either the inhibition or induction of apoptosis in a variety of neoplasms; therefore, it was hypothesized that the expression of these genes might contribute to malignant transformation in ovarian surface epithelial tumors. The expression of bcl-2 family proteins was investigated in 28 ovarian surface epithelial tumors, including serous and mucinous benign, borderline, and malignant tumors by immunohistochemical staining with antibodies to bcl-2, bax, bcl-X, and mcl-1 proteins. Staining intensity was scored on a 1+ to 3+ scale and the benign, borderline, and malignant tumors were compared. Significantly less immunoreactive bcl-2 and bcl-X proteins were present in malignant serous tumors compared to their benign counterparts. No difference was seen in immunostaining for bax or mcl-1 when benign, borderline, or malignant serous tumors were compared. In the mucinous tumors, no differences were seen in immunostaining for any of the bcl-2 family proteins between tumor types. The loss of expression of the antiapoptotic proto-oncogenes bcl-2 or bcl-X in serous carcinomas compared to benign serous tumors, together with previous demonstrations that the presence of bcl-2 in ovarian surface epithelial cancers is a favorable prognostic indicator, suggests that bcl-2 and bcl-X have biological functions in the ovary other than inducing apoptosis, acting instead as tumor suppressor proteins.
Wehrli
B M
BM
Department of Pathology, University of British Columbia, Vancouver, Canada.
Krajewski
S
S
Gascoyne
R D
RD
Reed
J C
JC
Gilks
C B
CB
D017209:Apoptosis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000032:analysis; D009375:Neoplasms, Glandular and Epithelial / Q000737:chemistry* / Q000473:pathology; D010051:Ovarian Neoplasms / Q000737:chemistry* / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000032:analysis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
C494826:BAX protein, human; C494811:BCL2L1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein