Factor interacting with poly polymerase

Over expression of tumor suppressor gene bcI-2 plays an important role in cellular resistance to apoptosis caused by various factors (77). Lin et al have shown that over expression of anti-apoptotic Bcl-2 and Bc1-Xl proteins may play a role in the development of resistance to cancer therapy 18). Functional over expression of Bcl-2 has been reported to confer an anti-apoptotic potential in a variety of cell types. The role of Bcl-2 in epithelial cell-cycle control and in interactions with other cell-cycle regulators is not clearly understood. Its expression has been correlated with the hormone- and chemo-resistant phenotype in advanced prostate cancer 19). Granville et al have shown that overexpression of Bcl-2 in HL-60 cells prevented apoptosis-related events including caspase 3 and 6 activation, poly (ADP-ribose) polymerase cleavage by photodynamic therapy (20). Over expression of HER2 in estrogen receptor (ER)-positive human breast tumors has been associated with resistance to endocrine therapy. 

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