This invention relates generally to a novel CaM multi-functional protein kinase, which has been named Pregnancy Up-Regulated, Nonubiquitous CaM Kinase (PNCK), and to the nucleotide sequence encoding it. The kinase is temporally expressed during postnatal mammary development in a spatially heterogeneous manner in certain subsets of cells, and overexpressed in a subset of primary breast cancers. The invention further relates to an analysis of a correlation between carcinogenesis and postnatal development, particularly mammary development, especially associated with parity; as well as to methods of using the kinase, or gene encoding it, as markers, prognostic tools, screening tools and therapies, in vitro and in vivo that are based upon that correlation.