Aim: The frequency and clinical significance of neuroendocrine features in conventional carcinomas has not been settled since few studies have been performed with conflicting results. The aim of this prospective study is to investigate neuroendocrine differentiation in colorectal carcinomas in relation to its prognostic significance. 
Methods: The resected specimens of sixty-two colorectal cancer patients were examined grossly and microscopically for 
histopathology, grades and stages. For neuroendocrine cell detection, immunohistochemical staining with anti-chromogranin A monoclonal antibody (Dako A/S, Denmark, cat. No MO869) was done. The distribution of positively stained cells was evaluated and divided into focal and diffuse patterns. The pattern of chromogranin a staining was correlated with the histologic type, grade, stage, disease free survival and overall survival. 
Results: Focal chromogranin a expression was detected in 71% of cases and diffuse staining in 29% of cases. Diffuse staining pattern of chromogranin A indicated more neuroendocrine differentiation of tumor tissue and was significantly correlated with histologic type, high grade and advanced stage of the tumors. Also, diffuse staining significantly lowered disease-free survival and overall survival; however, staging was the main predictor of survival 
Conclusion: Chromogranin A is a sensitive and specific neuroendocrine marker. Diffuse chromogranin A positivity appears to bear a poor prognosis in patients with colorectal cancers.