Expression and Significance of BP1 Gene and Cyclin D1 Gene in Breast Cancer.

BACKGROUND & OBJECTIVE: BP1, a novel transcriptional factor, belongs to DLX family of homeobox genes. Recent researches showed that BP1 gene is correlated to genesis of breast cancer, but its correlation to cell cycle control factor has not been reported yet. This study was to observe the expression of BP1 in breast cancer, and to make clear its correlation to Cyclin D1. METHODS: The expression of BP1 and Cyclin D1 in 86 specimens of human breast cancer and 20 specimens of normal breast tissue (3 cm away from primary tumor) was detected by reverse transcription-polymerase chain reaction (RT-PCR). BP1 poly antibody was made and was certificated by Western blot. The expression of BP1 and Cyclin D1 in 86 specimens of human breast cancer were detected by immunohistochemistry; their correlation was analyzed. RESULTS: The positive rate of BP1 mRNA was significanlty higher in breast cancer than in normal breast tissues (69.8% vs. 0, P < 0.001). The positive rate of Cyclin D1 mRNA was 64.0% in breast cancer. BP1 mRNA and Cyclin D1 mRNA were co-expressed in 52 specimens of breast cancer, and simultaneously negative in 23 specimens (P = 0.227); BP1 protein and Cyclin D1 protein were co-expressed in 43 specimens, and simultaneously negative in 31 specimens (P = 0.146). CONCLUSIONS: BP1 gene is highly expressed in breast cancer. There is co-expression of Cyclin D1 and BP1 in breast cancer. BP1 gene may promote the genesis of breast cancer through regulating the expression of Cyclin D1.