PRKCB and neoplasm: These mice are viable allowing for investigation of mammary tumorigenesis in the absence of PKCβ either throughout the whole animal as we investigated in MMTV–PyMT mice with and without PKCβ, or through transplantation approaches where we injected a MMTV–PyMT derived tumor cell line (B6 PyMT cells) into either WT or PKCβ null mammary fat pads.