Basal levels of RARα, RARβ, and RARγ mRNA splicing variants in mammary tumorsTotal RNA was extracted from the tissue slices deriving from the surgical specimens of breast cancer patients used in Fig3 before any treatment with DMSO or ATRA. RNA was subjected to RT-PCR analysis to determine the basal expression of the indicated RAR splicing variants.Each value represents the mean ± SD of two replicate measurements. The table shows the statistical significance of the indicated comparisons. *Significantly different (P-value < 0.05, Student's t-test). **Significantly different (P-value < 0.01, Student's t-test). 