Abstract: A method for assessing prognosis in a subject having a breast tumor comprises determining the level of expression of at least one Notch receptor gene, Notch ligand gene or Notch signaling target gene. A method of treating a subject suffering from a breast tumor associated with increased Notch signaling comprises administering to the subject an effective amount of an inhibitor of Notch signaling.

Abstract: The present invention describes the identification, isolation and characterization of novel mammalian proteins encoded by the Ese1 and Ese2 genes which are involved in endocytosis, vesicular trafficking and regulation of the actin cytoskeleton. Transcripts and products of these genes are useful for detecting abnormal cellular endocytosis processes as well as for developing assay systems to find and elucidate further binding partners of the proteins, to develop therapeutics to alter/restore protein function and for the isolation and manufacture of Ese proteins.