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Expression of Bcl‐2, but not Bax, correlates with estrogen receptor status and tumor proliferation in invasive breast carcinoma
Author(s) -
Yang Qifeng,
Sakurai Takeo,
Jing Xuefeng,
Utsunomiya Hirotoshi,
Shan Liang,
Nakamura Yasushi,
Nakamura Misa,
Oura Shoji,
Suzuma Takaomi,
Yoshimura Goro,
Umemura Teiji,
Kokawa Yozo,
Kakudo Kennichi
Publication year - 1999
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1046/j.1440-1827.1999.00942.x
Subject(s) - immunostaining , immunohistochemistry , estrogen receptor , apoptosis , breast carcinoma , biology , breast cancer , cancer research , lymph node , bax protein , pathology , estrogen , carcinoma , progesterone receptor , medicine , cancer , endocrinology , protein expression , gene , biochemistry
Bcl‐2 and Bax have been demonstrated to be associated with apoptosis in breast carcinoma, and the ratio between Bax and Bcl‐2 seems to be an important determinant of cellular sensitivity to induction of apoptosis. However, little information is available on the relationship between Bcl‐2, Bax and the proliferative activity of breast carcinoma. The purpose of this study was to investigate the significance of apoptosis‐related genes bcl‐2 and Bax and their correlation with expression of p53, tumor proliferation defined by MIB‐1 expression and estrogen receptor status. Immunohistochemistry was performed to determine Bcl‐2, Bax, p53, estrogen receptor (ER) and MIB‐1 expression in paraffin‐embedded tissues of 177 invasive breast cancers. Expression of the anti‐apoptotic protein Bcl‐2 was not correlated with the pro‐apoptotic Bax. Bcl‐2 immunostaining displayed a negative correlation with increasing histologic grade, p53 and MIB‐1 ( P < 0.0001, P < 0.05 and P < 0.0001, respectively) and a positive correlation with rising ER immunostaining ( r = 0.305, P < 0.0001). Conversely, expression of the apoptosis‐promoting protein Bax did not correlate with increasing histologic grade, p53, MIB‐1 or ER status. Neither Bcl‐2 expression nor Bax expression correlated with age, menopausal status, tumor size, histologic type or axillary lymph node status. These results imply that Bcl‐2 is associated with good prognostic markers and the regulation of Bax is complex and does not necessarily correlate with mutant p53 status in breast cancers.