Neuroendocrine differentiation in prostate adenocarcinoma biopsies and its correlation to histological grading

Prostate adenocarcinoma is frequently diagnosed on needle biopsies in early, organ-confined stages. New prognostic factors would help identifying at this stage patients at risk for unfavorable evolution, that would benefit from alternate therapy. This study aims to find correlations between the extent of neurocrine differentiation (NED), a feature commonly seen in prostate carcinoma, and known factors of disease evolution such as histological grade, malignant cell proliferation and serum PSA levels. Immunohistochemistry for choromogranin A and neuron-specific enaolase (NSE) was used to calculate expression scores in order to asses the extent of NED in prostate biopsies. Tumour proliferative activity was estimated by calculating percentages of Ki-67 immunoreactive cell nuclei. Results show that the presence of numerous clusters of chromogranin A positive cells is a feature that differentiate tumours with Gleason score 9 from those with a score of 6. Also, the same extended neuroendocrine differentiation is associated with high tumour proliferative activity. Multinomial regression analysis showed that high Ki indices, serum PSA values and NSE scores are predictive for moderately and poorly differentiated prostatic adenocarcinoma.