Analysis of β-catenin expression in membrane and free fractions. Membrane-associated β-catenin (blue), and free (yellow), fractions were analysed semi-quantitatively by laser densitometry of the western blots. Levels are represented as a percentage of the maximum per 5 μg of protein from each fraction. The membrane levels of β-catenin varied over a range of 70%. The CACO-2 control shows that the free component of β-catenin is substantially increased and is higher than its membrane component. The level of free β-catenin in the oesophageal SCC cell lines is low (WHCO3, WHCO5 and SNO) to negligible (WHCO1 and WHCO6). Note: the nature of this analysis does not lend itself to the inclusion of error bars.