DCBLD2 (discoidin, CUB and LCCL domain-containing 2; also known as ESDN and CLCP1) is a type I transmembrane protein that is structurally similar to neuropilin family proteins and contains the longest known amino-terminal secretory signal sequence among eukaryotic proteins (1). Highly expressed in nerve bundles, vascular smooth muscle cells and upregulated following vascular injury, DCBLD2 may be involved in a wide range of functions in the nervous and vascular systems (1,2). Studies have found DCBLD2 to be upregulated in several types of lung cancer with an especially high frequency in metastatic lesions and lymph node metastasis, implicating a role in the process of tumor progression and metastatic capability (3). DCBLD2 has also been identified as part of a complex EGF phosphotyrosine signaling network, serving as a novel tyrosine phosphorylation target of EGF signaling in human cancer cells (4). |