Table 3.

Relative gene expression measured by quantitative real-time RT-PCR.

	Relative expression levels in MCF-7 cells
Treatment	P21WAF1/CIP1	BCL-2	BAX
Experiment 1 (mean ± SD, n = 5)
Control	1 (c)	1 (c)	1 (c)
10−8 M B[a]P	1.2 ± 0.4	0.9 ± 0.3	1.1 ± 0.2
10−9 M E2	0.6 ± 0.1	0.9 ± 0.3	1.2 ± 0.2
Binary mixture	0.9 ± 0.2	0.9 ± 0.3	0.6 ± 0.6
Experiment 2
Control	1 (c)	1 (c)	1 (c)
10−6 M B[a]P	36.1	0.2	1.5
10−9 M E2	1.0	1.3	1.3
Binary mixture	35.5	0.1	1.4
Experiment 3
Control	1 (c)	1 (c)	1 (c)
10−8 M B[a]P	1.1	1.3	1.0
10−11 M lindane	0.7	1.2	1.0
Binary mixture	0.9	1.0	1.0
Experiment 4
Control	1 (c)	1 (c)	1 (c)
10−6 M B[a]P	56.3	0.3	2.1
10−11 M lindane	1.9	2.0	2.9
Binary mixture	47.9	0.3	2.2
Experiment 5
Control	1 (c)	1 (c)	1 (c)
0.5 μM PhIP	1.4	1.2	1.4
10−9 M E2	0.8	1.0	1.6
Binary mixture	0.6	0.7	1.1

^(c) calibrator, which for the purposes of these experiments were untreated controls. Relative gene expression levels following 24-hr treatment in the presence or absence of test agents, as indicated. Reverse transcription of total RNA and subsequent amplification was carried out using primers as described in “Materials and Methods.” Within each experiment, reactions were performed in triplicate and “no-template” controls were included. Averaged threshold cycle (C_T) values for each reaction were normalized to β-ACTIN values thus giving ΔC_T values. Alterations in gene expression were determined by comparing treatment groups with the calibrator, giving ΔΔC_T values. Finally, relative gene expression was calculated using the formula 2^−ΔΔC_T.