Men whose prostate cancer screenings show high grade prostatic intraepithelial neoplasia (HG-PIN) may find themselves in limbo, "stuck" between diagnoses - they are told prostate cancer has not yet developed, but it might, and they are advised to undergo repeated needle biopsies as a precaution.
Investigators from Spain have found a means of distinguishing between HG-PIN lesions destined to become cancerous and those which will remain benign. Their findings, reported in the May 1 issue of Clinical Cancer Research, a journal of the American Association for Cancer Research, could spare patients the discomfort and inconvenience of unnecessary needle biopsies.
The Spanish team found that expression of the PTOV1 gene in HG-PIN lesions is linked to prostate cancer development, and that the higher the expression, the more likely it is that subsequent biopsies will find cancer. The reverse is also true-lack of PTOV1 reduces the risk of prostate cancer.
"This is the first HG-PIN biomarker to be associated with prostate cancer development," said the study's lead author, Rosanna Paciucci, Ph.D., a researcher at the Vall d´Hebrón Hospital Research Institute in Barcelona. She says that when the results of this study are validated, the PTOV1 gene marker could be used to determine which men with HG-PIN are at substantial risk of developing prostate cancer.
"Those patients with a high PTOV1 score should undergo an immediate repeat biopsy," Paciucci said. On the flip side, men who test low for PTOVI may not need to receive future "annoying and useless" biopsies, she said. "We estimate that we can save 40 percent of unnecessary biopsies - those that are repetitively negative and contain HG-PIN lesions that do not develop into cancer."
While the researchers do not know the precise biochemical function of PTOV1, they say they have found this protein promotes the proliferation of cancer cells when it is over-expressed, as it occurs in prostate cancer cells.
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.