Analysis of L1 and CLU expression in tumor tissue samples from the site of injection in the spleen and from liver metastases confirmed that these cells continued to express L1 and CLU in liver metastases in L1 overexpressing cells (Fig. 5C, lanes 4 and 6), but while continuing to express L1, they did not express CLU in mice injected with L1+shCLU Cl1 and Cl2 CRC cell clones (Fig. 5C, lanes 8, 10, 12 and 14). This evidence concerns the gene CLU and colorectal carcinoma.