Prostate cancer is diagnosed from the results of a biopsy of the prostate gland. If the digital rectal exam of the prostate or the PSA blood test is abnormal, a prostate cancer is suspected. A biopsy of the prostate is usually then recommended. The biopsy is done from the rectum (trans-rectally) and is guided by ultrasound images of the area. A small piece of prostate tissue is withdrawn through a cutting needle. The TRUS-guided Tru-Cut biopsy is currently the standard method to diagnose prostate cancer. Classically a 6-core set is taken by sampling the base, apex and mid gland on each side of the gland. More cores may be sampled to increase the yield, especially in larger glands. A pathologist then examines the tissue under a microscope for signs of cancer in the cells of the tissue.