The Expression And Significance Of Bcl-2 And Bag-1 Protein In Breast Cancer

Apoptosis is a distinct mode of cell death that has been shown to differ from necrosis by morphological and biochemical features that include cytoplasmic and nuclear condensation, subsequent formation of membrane-bound apoptotic bodies and oligonucleosomal DNA degradation. Unlike necrosis, apoptosis is characteristically not associated with an inflammatory cell infiltrate. Apoptosis results in physiological cell deletion during development in a variety of tissues and organisms, it also occurrs spontaneously in malignant tumors and is increased in tumors responding to irradiation, cytotoxic chemotherapy, heating, hormone ablation and other anti-cancer therapies. Apoptosis increasingly has been attracting oncologists' attention for the discovery that apoptosis can be regulated by certain proto-oncongenes and tumor suppressor gene P.^.Among these apoptosis regulator proto-oncogenes, Bcl-2 inhibits apoptosis rather than stimulating cell division.In investigating the genes' structures of bcl-2-associated proteins , Takayama S etc(1995) identified an associated 274 amino acids protein parter, bag-1. Bag-1 protein encoded by bag-1 gene which called bcl-2-associated athanogene 1, has no amino acid homology with bcl-2 protein. So, bag-1 is a novel bcl-2-binding protein. The protein functions are inhibiting apoptosis with binding to bcl-2 and restraining cell death independently.Besides apoptosis regulator activity, bcl-2 and bag-1 are related to a variety-4-of malignant tumors such as breast cancer, lung cancer etc, by showing different effects on their development, progression, therapy and outcom.The relationship of bcl-2,bag-l and breast cancer have not been reported in internal.To evaluate bag-1 and bcl-2 expressions in breast cancer and to evaluate its clinical significance. Bcl-2 and bag-1 expressions were studied by immunohistochemstry Streptavidin-Biotin-Peroxidase Complex (SABC) methods in 100 samples of breast cancer tissues and in 10 normal breast tissues and in 10 benign tumor tissues, and their clinical significance were analysed. The positive rate of bag-1 expression among breast cancer , benign tumor and normal tissues were 85.0%,10.0%.10.0% respectively,and significant difference were observed (p<0.05). However, the positive rate of bag-1 expression is not related to the pathologic grades and the different clinical type(p>0.05). The positive rate of bcl-2 expression among breast cancer , benign tumor and normal tissues were 46.0%,80.0%,90.0% respectively.and significant difference were observed (p<0.05). The positive rate of bcl-2 expression is not related to the pathologic grades and the different clinical type (p>0.05). .Following up the one hundred breast cancer patients,we know that 74 patients survived ^ 5-year whose bag-1 expression is positive,and 41 patients survived ^? 5-year whose bcl-2 expression is positive.The observations suggested following conclusions:(Dln breast cancer, apoptosis is mediated by more than one genes, compare to bag-1 and bcl-2. the apoptosis regulator activity of bag-1 is more dominant. ㏕he positive rate of bcl-2 and bag-1 expression is not related to the pathologic grades and the different clinical type . (3)Bag-l and bcl-2 might serve as a biomarker to diagnose the earlier period breast cancer and bag-1 might even more serve as a biomarker to prognose the earlier period breast cancer. 〥ecrease of apoptosis plays a role in the over-growth of BC and affects the clinic pathology, therapy and outcome of BC.