HG-PIN is defined as a pre-malignant lesion present in most cancerous prostates. Although a pre-malignant lesion shows many of the typical cellular changes observed in cancer, the lesion has not yet progressed fully to disease. Since HG-PIN lesions are also associated with the presence of cancer in many patients, men whose biopsies show HG-PIN are often re-biopsied until cancer is detected, Paciucci says.
In most recent studies, the average risk of cancer following a diagnosis of isolated HG-PIN in biopsy ranged from 20 percent to 30 percent, the researchers say. And while other researchers have found markers in HG-PIN lesions, none have been able to discriminate between lesions that will progress to cancer, the researchers say.
In this study, the research team analyzed HG-PIN lesions from 140 patients: the positive control group comprised 79 patients diagnosed with prostate cancer who had their prostate glands surgically removed and who had been earlier diagnosed with HG-PIN; the negative control group included 11 patients with bladder cancer who had both their diseased bladder and healthy prostate removed; and the study group comprised 50 patients diagnosed with HG-PIN but not prostate cancer. The study group had an average of 2.5 biopsies each between 2000 and 2004.
Finding that PTOV1 gene expression was elevated in HG-PIN associated with cancer, the investigators used tissue microarray and immunohistochemical analyses to see whether PTOV1 protein levels could discriminate these pre-malignant lesions from HG-PIN that did not develop into prostate cancer.
They considered both the number of cells that express the protein and the intensity of the expression, and derived a quantitative score (Hscore) that ranged from 0 to 300. From this, they calculated that an Hscore of 100 represented a highly sensitive malignancy threshold. This means that when PTOV1 Hscore is equal or above 100 the possibility
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American Association for Cancer Research