The invention is directed to compositions and methods for the detection of a malignant condition, and relates to the discovery of soluble and cell surface forms of HE4a polypeptides, including HE4a that is overexpressed in ovarian carcinomas. In particular the invention provides a nucleic acid sequence encoding HE4a, and also provides a method of screening for the presence of a malignant condition in a subject by detecting reactivity of an antibody specific for a HE4a polypeptide with a molecule naturally occurring in soluble and/or cell surface form in a sample from such a subject, and by hybridization screening using an HE4a nucleotide sequence, as well as other related advantages.