Prostate cancer genetic 'bar codes' predict aggressiveness

In two separate papers published in The Lancet Oncology, researchers have found two gene signatures, or "bar codes," that can predict how severe and aggressive prostate cancer could become, potentially improving accuracy of diagnosis and prognosis and supporting treatment decisions. They could potentially be used alongside the existing prostate-specific antigen test.

Outcomes for prostate cancer range from no symptoms at all, through slow-progressing disease, to cancer that is resistant to standard therapy (known as castration-resistant prostate cancer), and treatments and survival times differ for all these types. More accurate tests than are currently available would help doctors make better decisions about treatments, and allow patients with more or less aggressive cancers to be grouped for clinical trials.

In one study, led by the U.K.-based Institute of Cancer Research, the researchers screened blood from patients with castration-resistant prostate cancer or with prostate cancer that was under active surveillance ("watch and wait"). They found a set of 9 genes that could potentially predict whether patients had metastatic castration-resistant prostate cancer. The patients with this genetic signature survived for a median 9 months, compared with 22 months for those without this gene pattern.

Johann de Bono of the Institute of Cancer Research said: "Our test reads the pattern of genetic activity like a bar code, picking up signs that a patient is likely to have a more aggressive cancer. Doctors should then be able to adjust the treatment they give accordingly."

In a second study, led by the Tisch Cancer Institute of Mount Sinai School of Medicine, researchers screened blood from patients with castration-resistant prostate cancer and found a 6-gene signature that signified more aggressive prostate cancer, which could predict whether patients were high risk (median survival 8 months) or low risk (median survival 35 months).

According to Karina Dalsgaard Sørensen at Aarhus University Hospital in Denmark, "Scarcity of prognostic markers presents a major challenge for the clinical management of castration-resistant prostate cancer. These results suggest that a few selected genes in blood samples from patients with castration-resistant prostate cancer can significantly improve the prediction of outcomes."

She adds that these are the first prognostic signatures of this kind, so their biological relevance is largely unknown and further investigation is needed.

- read the press release from Cancer Research UK
- see the abstract for the 9-gene set
- check out the abstract for the 6-gene set