CAV1 and melanoma: However, since melanoma may express heterogeneous or low amount of MelanA/MART-1, especially at metastatic levels [27], [28], and CEA is present mostly in soluble form in CRC patients serum, we considered Cav1 a more reliable and reproducible tumor marker, thus the Exotest was further developed with the inclusion of anti-Cav1-specific antibodies.