Khor L-Y et al. (2008) Protein kinase A RI-α predicts for prostate cancer outcome: analysis of radiation therapy oncology group trial 86-10. Int J Radiat Oncol Biol Phys 71: 1309–1315

Protein kinase A type I (PKA) mediates cell processes such as DNA replication and cell proliferation in mammalian cells. Overexpression of PKA is associated with poor prognosis in studies of patients with breast, colon and lung cancers. Khor and colleagues have now investigated the predictive value of PKA overexpression in men with prostate cancer.

Both manual and image-analysis methods were used to score the immunohistochemical staining intensity of PKA expression in pretreatment biopsies obtained from 80 men who participated in the phase III, randomized, Radiation Therapy Oncology Group (RTOG) trial 86-10. This trial compared the effects of radiotherapy alone with radiotherapy plus short-term androgen deprivation therapy in men with prostate cancer.

On univariate analysis, significant associations were identified between PKA overexpression and cause-specific mortality (P = 0.037 scored manually and P = 0.014 scored by image analysis), distant metastasis (P = 0.029), local failure (P = 0.011) and biochemical failure (P = 0.022). On multivariate analysis, the relationships between PKA overexpression and biochemical failure (P = 0.03), local failure (P = 0.002) and distant metastasis (P = 0.018) remained significant.

In this small group of men with prostate cancer, PKA overexpression seemed to be a stronger determinant of outcome after radiotherapy than the addition of short-term androgen deprivation therapy was. The authors suggest that PKA overexpression could be a potentially useful biomarker for patients with high-risk prostate cancer, but further studies are needed to confirm these results.