Yale University researchers have discovered a potential new biomarker for identifying individuals with increased risk of prostate cancer metastasis. The findings, published in The American Journal of Pathology, announced that mitochondrial protein syntaphilin (SNPH) is vital in determining the balance between tumour cell proliferation and tumour cell invasion, and is expressed significantly at the invasive tumour edge in prostate cancer.

The researchers also determined that SNPH expression increases as the Gleason pattern does. Research into patients undergoing radical prostatectomy has found that low central tumour expression is linked to an increased risk of metastasis.

To get their results, the researchers looked at 89 individuals with prostate adenocarcinoma who had had their prostate removed. They found that SNPH is created in a unique spatial distribution in prostate tumours, with SNPH levels raised at the outer invasive edge (where it correlates with increased tumour cell proliferation), but decreased at the tumour core, in 96% of cases studied.

In the study, central tumour SNPH measures were much lower in 16 patients with metastases compared to those without, while SNPH scores at the invasive edges were the same in both types of patient.

The authors said that: “SNPH distribution in prostate cancer is spatially biphasic, with high expression at the invasive front, correlating with increased proliferative rates, as determined by Ki-67 labelling, and reduced levels in the central tumour bulk, which are further decreased in patients with distant metastases. Higher levels of SNPH were observed with increasing Gleason grade. Prostate tumours predominantly express a novel, extraneuronal isoform of SNPH that accumulates in mitochondria and maintains oxidative metabolism and tumour cell proliferation.”