Cyokeratin 19 is a key cytoskeletal protein in endothelial cells. CK19 is released by colorectal and breast cancer cells. The presence of CK19-releasing cells has been correlated with metastasis.
Alix-Panabieres, C. et al. (2009) Full-length cytokeratin 19 is released by human tmor cells: a potential role in metastatic progression of breast cancer. Breast Cancer Research. 11:R39. Doi:10.1186/bcr2326