Biological samples of mammary fluid or components thereof are obtained using a breast pump device coupled with an absorbent paper or membrane, optionally facilitated by administering oxytocin to the subject. The breast pump device stimulates expression of mammary fluid and provides for collection of diagnostic samples on the absorbent paper or membrane to evaluate breast disease, including cancer. The biological sample may include fluid containing one or more of cells or cellular components, proteins, glycoproteins, peptides, nucleotides or other desired constituents comprising a breast disease marker. Absorbent paper or membrane, and methods relating to the paper or membrane, and a breast pump device are also provided.
