The course of neuroendocrine differentiation in prostatic carcinomas. An immunohistochemical study testing chromogranin A as an "endocrine marker".

To gain further insight into the pathogenetic aspects of neuroendocrine (NE) differentiation in prostatic carcinoma, the incidence of NE manifestations was studied during tumour progression in the course of the disease. This follow-up took the form of semiquantitative assessment of the NE cells in carcinomas by means of repeat biopsies at intervals of a few years, correlating the findings with those of conventional histopathological grading of the prostatic tumours. Immunoreactivity to chromogranin A (ChrA) and the Grimelius silver-staining technique were used to detect NE cells. A strong correlation was observed in all the 25 carcinomas studied between the results obtained with the Gimelius silver-staining and those obtained on the basis of immunoreactivity to ChrA. In addition, cells immunoreactive to an antiserum against ChrA found in virtually all sections from 24 cases of hyperplastic prostatic glands were found to be almost invariably argyrophil. Most of the 25 carcinomas underwent marked tumour progression, while the number of NE cells concomitantly increased. An unequivocal relationship can be stated between the degree of NE differentiation and tumour progression in our series of prostatic carcinomas treated with steroids-i.e., the more anaplastic the prostatic carcinoma, the more numerous are its NE cells. ChrA may be considered to be a sensitive marker for NE cells both in hyperplasia and in prostatic carcinomas.(ABSTRACT TRUNCATED AT 250 WORDS)