1. An in-vitro protein test method for diagnosing whether a primary breast tumor from an individual human subject is a clinically metastatic tumor, said in-vitro protein test method comprising the steps of: obtaining a specimen of breast tumor cells representative of a primary tumor found clinically in the breast of an individual human subject; fractionating said specimen to yield a cytoplasmic fraction and a nuclear fraction; fractionating said nuclear fraction to yield a proteinaceous fraction; separating at least a part of said proteinaceous matter fraction from said nuclear fraction; and detecting an absence of the nmt55 protein in said separated proteinaceous matter fraction, said detected absence of the nmt55 protein in said proteinaceous matter fraction indicating that the primary breast tumor found in the individual human subject is a clinically metastatic tumor.