Granins and prostate cancer

Abstract

Objectives: The importance of the expression of granin A (GRN-A, chromogranin-A) has become appreciated in the neuroendocrine differentiation of prostate cancer. We studied the expression of GRN-A in prostate cancer using serum immunoassay and tissue immunohistology procedures for this protein in order to define the clinical value of its measurements. Methods: GRN-A production was measured by immunoassay in serum samples from patients with prostate cancer. Immunohistology procedures were used to assess GRN-A expression in paraffin-embedded prostate tissue samples. Serum and tumor findings were evaluated according to the patient’s clinical status in studies by us and others. Results: These studies demonstrated that GRN-A can serve as a prostate cancer serum and tumor marker with clinical value for both diagnosis and prognosis. Serum GRN-A was increased in early- and late-stage disease. Elevated serum GRN-A levels identified some patients with prostate cancer who did not have elevated serum prostate-specific antigen levels. In addition to their diagnostic value, increased serum GRN-A concentrations had prognostic value. Conclusions: Our own studies as well as those of others support the clinical potential of GRN-A as a marker for early, progressive, and recurrent prostate cancer. This demonstration of clinical utility notwithstanding, further studies are needed to clearly define the clinical value of GRN-A as a serum and tumor marker for this common cancer.