EFNA1 and neoplasm: However, based on a recent study showing that ephrin-A1 may be released from some types of tumor cells and can elicit cellular responses that are not dependent on juxtacrine interactions11, we became interested in determining whether soluble ephrin-A1 (sEphrin-A1) is secreted by BCa cells and thereafter exerts a more extensive pro-angiogenic effect on endothelial cells through a paracrine pathway in complex tumors, such as BCa.