Serum levels of Magic Roundabout protein in patients with advanced non-small cell lung cancer (NSCLC).

Background: Magic Roundabout (MR; ROBO 4) is a recently discovered gene which encodes a protein that derived its name form the structural homology with the roundabout family of genes. Genes of the roundabout family comprise neuronal-specific cell surface receptors that are involved in axon guidance. MR in contrast showed endothelial specificity in vitro and in vivo using immunohistochemistry and in situ hybridisation. The putative role of MR as an endothelial analogue of Roundabout in angiogenesis makes it an attractive target for anti-angiogenic cancer therapy.

Patients And Methods: Using specific antibodies against MR peptide, we screened pretreatment sera from 193 patients with advanced non-small cell lung cancer (NSCLC) for MR-protein levels.

Results: Patients with serum levels of MR-protein lower than median (E(450 nm) = 0.652) had a median survival of 41.0 weeks whereas those with a higher serum level had a considerably shorter median survival of 32.4 weeks (P = 0.05). The pretreatment serum level of MR-protein achieved no significance in a univariate Cox regression analysis.

Conclusions: This is the first study to present clinical data that link MR expression with outcome in patients with NSCLC, whether the correlation of pretreatment serum levels of MR and survival can be attributed to MR dependent angiogenesis remains to be investigated.