Reciprocal expression of survivin and SMAC/DIABLO in primary breast cancer

There is an intimate relation between disturbance in survivin and SMAC/DIABLO expressions and cancer formation in many tissues; however, this was not confirmed in the primary breast cancer. The aim of this study was to evaluate the relationship between survivin and SMAC/DIABLO mRNA expressions in primary breast cancer using RT-PCR and their relationship to some of the risk factors (age, family history, breast-feeding, use of contraceptive pills and hormonal receptors). Breast cancer tissues were studied for the detection of the mRNA expression of survivin and SMAC/DIABLO. This was done by qualitative reverse transcription-polymerase chain reaction (RT-PCR). SMAC/DIABLO mRNA was detected by RT-PCR only in 1 sample in breast cancer tissues (6.25%). However, it was expressed in 16 out of 25 (64%) of the benign tumor tissues (P=0.00). In contrast, survivin mRNA was highly expressed in breast cancer tissues, 36 out of 48 (75%) (P=0.00), while its expression was very low in benign tumor tissues, only 1 out of 37 (2.7%) (P=0.00). Expressions of SMAC/DIABLO and survivin were significantly reciprocal in breast cancer and benign tumor tissues. SMAC/DIABLO inhibits apoptosis of breast cancer cells by suppression of survivin. These two genes probably form an important link in the signaling pathway of formation of breast cancer cells, which may be chosen as therapeutic targets in the primary breast cancer.