NEUROENDOCRINE DIFFERENTIATION IN METASTATIC PROSTATIC ADENOCARCINOMA

Neuroendocrine differentiation of prostatic adenocarcinoma has receive d considerable attention in recent years. The objectives of this study were to characterize the incidence, pattern of distribution and pepti de hormone immunoreactivities of neuroendocrine differentiated tumor c ells in prostatic carcinoma metastases; determine the correlation of n euroendocrine differentiation and deoxyribonucleic acid content in lym ph node metastases, and determine the prognostic role of neuroendocrin e differentiation of metastases in stage D1 cancer. We examined immuno histochemically 62 metastatic lesions (41 pelvic lymph nodes and 21 bo ne metastases) for the presence of chromogranin-A expressing tumor cel ls. Of 41 lymph nodes and 21 bone metastases 19 (46%) and 11 (52%), re spectively, contained chromogranin-A immunoreactive cells. These cells were commonly found to comprise the minority of tumor cells in the me tastases and typically were distributed in a dispersed pattern. Seroto nin and peptide hormone immunocytochemistry in 19 cases (12 lymph node s and 7 bone metastases) demonstrated neuroendocrine cells containing thyroid-stimulating hormone and serotonin in 17 (89%) and 10 (53%), re spectively. All 7 bone metastases contained thyroid-stimulating hormon e immunoreactive cells. The presence of chromogranin-A positive cells did not correlate statistically with deoxyribonucleic acid content of lymph node metastases nor with disease specific survival in patients w ith stage D1 prostate cancer. Our results indicate that a substantial proportion of prostate cancer metastases contain a subpopulation of ce lls expressing a neuroendocrine phenotype similar to primary tumors. T hese cells are capable of elaborating certain biogenic amines and pept ide hormones. However, in stage D1 prostate cancer nodal lesions expre ssing neuroendocrine differentiation do not appear to have significant prognostic value.