Vesicles released from aggressive prostate cancer cells with highly migratory features, known as large oncosomes, may be a new source of biomarkers for aggressive prostate cancer.

Many patients with prostate cancer have indolent, slow-growing forms of the disease that are not life-threatening. However, more than 30,000 American men will die from aggressive prostate cancer this year alone. This sharp contrast between low-risk and aggressive disease presents a challenge for many researchers and physicians as they diagnose the cancer and also determine the prognosis of the men with the most aggressive forms of prostate cancer.

Investigators at the Cedars-Sinai Samuel Oschin Comprehensive Cancer Institute in Los Angeles, California, have made extensive progress in understanding the molecular mechanisms of disease progression. These results may help scientists better understand the prognosis of patients diagnosed with advanced prostate cancer.

This study, published in Cell Cycle (2013; doi:10.4161/cc.26539), and led by Dolores Di Vizio, MD, PhD, may ultimately lead to the development of new biomarkers for not only prognosis, but also a patient’s potential response to therapy.

The large oncosomes carry tumor molecules. Previous studies have shown that they contribute to tumor progression. This study demonstrates, for the first time in human samples, that identifying circulating large oncosomes can be an indicator of patients with more aggressive, treatment-resistant disease. Also notable, researchers found that large oncosomes contain microRNA, a molecule that regulates several biological processes now proven to influence tumor progression.

“One of the long-standing difficulties in treating men with advanced prostate cancer has been predicting the response to given therapies or treatments,” said Di Vizio, associate professor in the Department of Surgery, Department of Pathology and Laboratory Medicine and Department of Biomedical Sciences. “These latest research findings provide tangible insight into the molecular and structural phenomena that result in prostate cancer metastases. They have the potential to create a new source of biomarkers and an innovative standard of care. These findings may also help distinguish individualized treatment plans best suited for each patient.”