Western blot analyses of oesophageal SCC and CACO-2 cell extracts. 5 μg of protein from a) the membrane and b) the cytoplasmic/nuclear (free) cellular fractions were separated on SDS-PAGE and blotted specifically for β-catenin. Lanes 1–6 represent WHCO1, WHCO3, WHCO5, WHCO6, SNO and CACO-2 cell lines, respectively. a) The presence of β-catenin was identified in the membrane fractions of all cell lines (94 kD, black arrow). An 80 kD band was also exposed (red arrow) previously reported as a partial degradation product [22, 57]. b) CACO-2 cell line, possessing stabilised cytoplasmic β-catenin , exhibits a strong β-catenin band in the free fraction (black arrow). This is in sharp contrast to extremely low free β-catenin concentrations in the oesophageal SCCs.