To further characterize the 67LR in colorectal cancer cells, we used different cell fractionation protocols that led to two unexpected findings: 1) The immunoreactive 67 kDa RPSA-related components were predominantly found under a soluble form in cell lysates and 2) Part of the cellular RPSA can be isolated in membrane protein fractions and can be released after membrane solubilization. Here, RPSA is linked to colorectal cancer.