An embodiment of the invention is a method of using a xenograft as a control tissue for
histology, comprising
staining both a patient and a xenograft-derived
control sample under substantially similar
staining conditions, and assessing the
staining outcomes of the two to determine whether the
stain was effective for the patient sample. A xenograft has never been used before in
histology as a control, as far as the inventors know. The result of using a xenograft as a control is surprisingly advantageous. First, the
cell lines grow and differentiate similarly to a human, taking on the general morphology of a real
tissue sample. Second, because the same
transformed cell line can be grown limitless times in
SCID mice, the xenograft control is highly reproducible, leading to a consistent artificial control that is highly manufacturable and subject to genetic manipulation so that antigens or genetic elements may be embedded in the tissue. Another embodiment of the invention is directed generally to a method of making a tissue control substrate, comprising growing a xenograft from a mammalian
transformed cell line in a host animal, removing the xenograft from the host animal,
processing the xenograft thereby embedding the xenograft tissue in an
embedding medium, and finally affixing the embedded xenograft sample onto a substrate. The substrate is generally a
microscope slide. The xenograft control slide can then be stained side-by-side with a specimen sample in an automated slide stainer, and act as a control against which the staining quality can be compared. The xenograft control can also be used as a manual staining control. Determining whether the staining was effective for the patient specimen comprises judging the staining intensity of the xenograft
control sample to determine if the expected degree and type of staining were realized in the control. If the expected type (nuclear, membranous, or cytoplasmic) and degree (0-4 scale) of staining are realized during the run, then the xenograft control indicates the staining process and reagents are working properly, and so the result in the patient specimen can be trusted. A further embodiment of the invention is a xenograft-derived control slide for histochemical use, comprising at least one xenograft
control sample prepared for histological use, and a sample slide upon which the at least one xenograft control sample is affixed.