Fold repression of hTERT gene expression in breast cancer cell lines- TatHA control. Fold changes in hTERT gene expression compared to TatHA control in breast cancer cell lines. HCC1937 and HCC1599 cells were treated for 24 hours with 2 μM Tat fusion proteins. RNA was isolated and RT-qPCR performed as described under Materials and Methods. The asterisks (*) indicate statistically significant fold changes in gene expression. A significant 3.5-fold repression of hTERT gene expression was observed in HCC1937 cells treated with E2F-1/TatHA proteins in comparison to treatment with TatHA control proteins (p < 0.0024). Repression of hTERT in HCC1937 cells treated with E132/TatHA proteins versus the TatHA control proteins was not statistically significant (p < 0.6484). A 3.3-fold repression of hTERT was observed in HCC1599 cells treated with E2F-1/TatHA proteins versus the TatHA control protein (p < 0.0001). hTERT gene expression was slightly increased (1.15-fold increase) in HCC1599 cells treated with E132/TatHA proteins versus the TatHA control proteins (p < 0.0102). The results are means +/- SEM of three separate experiments (HCC1937, n = 17; HCC1599, n = 18).