Immunohistochemically, the tumour cells were negative for PSA and positive for chromogranins (Fig.
In this case, immunostains for PSAS, prostate-specific acid phosphatase, cytokeratin 7, cytokeratin 20 were negative, while those for chromogranin and synaptophysin were strongly positive - these factors helped in the diagnosis.
Immunostaining for chromogranin showed diffuse cytoplasmic reactivity (inset).
Chromogranins are matrical proteins that are associated with neurosecretory granules and as such they are absolutely specific for NE differentiation (20).
With the hypothesis that histidine decarboxylase (HDC) and its mechanism of releasing and regulating biogenic amines and peptides, may outline a significant link between NE differentiation of any malignancy, we studied the immunohistochemical expression of this marker, along with chromogranin A (CgA), in various subtypes of PNECs.
Key words: Neuroendocrine, pulmonary neuroendocrine carcinomas, chromogranin A, histidine decarboxylase, immunohistochemistry
Staining was positive for pan-cytokeratin and negative for chromogranins, nonspecific esterase, synaptophysin, and S-100, supporting the diagnosis.
Immunohistologic analysis is critical to establishing a diagnosis, particularly staining for chromogranins and S-100.
The results of a biopsy taken at that time the nasal mucosa was positive for HMB-45 and melan-A (figure 1, A and B) and negative for S-100, pan-cytokeratin, synaptophysin, chromogranins, and Epstein-Barr virus (EBV) immunoperoxidase--were consistent with malignant melanoma.
Immunohistochemical staining was positive for HMB-45 and S-100 and negative for pan-cytokeratin, epithelial membrane antigen, synaptophysin, chromogranins, and EBV immunoperoxidase.
Human chromogranin A (CgA), a member of the granin family, is an acidic 439-amino acid protein with a widespread expression in endocrine cells and neurons (1-3).
To evaluate the chromatographic separation of labeled and nonlabeled peptides, 1 mL of the monoiodinated peak fraction was mixed with 10 pmol of the relevant synthetic tyrosine-extended chromogranin A fragment and reapplied to the HPLC column as described.