A strategy to identify genes associated with circulating solid tumor cell survival in peripheral blood.

Efforts in metastasis research have centered on the phenotypic and genetic differences between primary site and metastatic site tumors. However, genes that may be used as molecular markers of metastasis in circulating tumor cells remain unidentified. Genes regulating the dissemination and survival of solid tumor cells in the blood, as well as their adaptation to new environments, could be candidates for unique metastatic tumor markers. Differential display (DD) was conducted to compare the blood of tumor-free individuals with the blood of patients with lung, breast, and colon cancers. Twenty-one up-expressed genes in the tumor patient blood samples but none in the tumor-free donor blood samples were identified. Nine of these samples were isolated, amplified, and directly sequenced. A gene AB-1 homologous to a Bcl-2 family member, which might function as an apoptosis inhibitor, was identified. The overexpression of an apoptosis inhibitor in blood from patients with metastatic tumors might be correlated with the capability of solid tumor cells to survive in peripheral blood. This is the first demonstration of the usefulness of comparing control and patient blood samples by DD to find novel potential genetic markers identifying metastasis in the blood. http://link.springer-ny. com/link/service/journals/00020/bibs/5n5p313.html