Disease:
Used to help differentiate between benign versus malignant and increasingly used to grade various tumors (e.g. neuroendocrine tumors, pituitary tumor, schwannoma, meningioma, sarcoma, etc.) or dysplasia (cervical intraepithelial neoplasia, anal intraepithelial neoplasia, dysplasia arising in Barrett, etc.)
Used to determine prognosis of breast cancer, bladder cancer, prostate cancer and chordoma

Marker of cell proliferation. Labile, nonhistone nuclear protein expressed in G1, S, G2 and M phases of cell cycle, then rapidly catabolized at end of M phase and not detectable in G0 and early G1 cells. The expression of the Ki-67 protein is used to assess tumor cell proliferation in breast cancer.
The Ki-67 labeling index which is the fraction of Ki-67-positive tumor cells is often correlated with the clinical course of the disease.

Collection:
FFPE/un-stained slides/Fresh tissue in formalin

Stability:
Room temperature

Unacceptable Conditions:
Unlabeled specimen/specimen left unfixed
for extended periods