Expression of Siah1 and Siah2 in SKBR3 cells. A: All but the MCF-7 breast cancer cells lacked expression of Siah1 and Siah1L. mRNA expression was determined by RT-PCR. GAPDH was used as an internal control. B: Ectopic expression of Siah1, Sial1L or Siah1ΔR in SKBR3 cells. Cells were stable transfected with plasmids encoding FLAG- tagged Siah1, Sial1L or Siah1ΔR proteins. Protein level was determined by Immunoblot analysis with anti FLAG antibody.