Tissue samples can be stained for the presence of PSA and other tumor markers in order to determine the origin of malignant cells that have metastasized.
Small cell carcinoma is a very rare (1%) type of prostate cancer that cannot be diagnosed using the PSA. As of 2009 researchers are trying to determine the best way to screen for this type of prostate cancer because it is a relatively unknown and rare type of prostate cancer but very serious and quick to spread to other parts of the body. Possible methods include chromatographic separation methods by mass spectrometry, or protein capturing by immunoassays or immunized antibodies. The test method will involve quantifying the amount of the biomarker PCI, with reference to the Gleason Score. Not only is this test quick, it is also sensitive. It can detect patients in the diagnostic grey zone, particularly those with a serum free to total Prostate Specific Antigen ratio of 10-20%.
The oncoprotein BCL-2, has been associated with the development of androgen-independent prostate cancer due to its high levels of expression in androgen-independent tumours in advanced stages of the pathology. The upregulation of BCL-2 after androgen ablation in prostate carcinoma cell lines and in a castrated-male rat model further established a connection between BCL-2 expression and prostate cancer progression.
The expression of Ki-67 by immunohistochemistry may be a significant predictor of patient outcome for men with prostate cancer.
ERK5 is a protein that may be used as a marker. ERK5 is present in abnormally high levels of prostate cancer, including invasive cancer which has spread to other parts of the body. It is also present in relapsed cancer following previous hormone therapy. Research shows that reducing the amount of ERK5 found in cancerous cells reduces their invasiveness.
