Immunogold detection of chromogranin A in the neuroendocrine tumor.
Immunogold ultrastructural localization of chromogranin A in secretory granules within tumor cells provides convincing evidence of endocrine or neuroendocrine differentiation. A modified immunogold method (designed for use on osmicated tissue) produced positive labeling of small granules not only in well-differentiated tumors but also in poorly differentiated small cell tumors primary in lung, cervix, and skin; only a proportion of granules in some of the tumor cells were positively labeled. Many non-small cell lung tumors often stain focally positive for chromogranin A at the light microscopy level, and such tumors may also contain sparse, small, dense granules. Because positive labeling could not be demonstrated over small granules in non-small cell lung tumors, the theory that such tumors are neuroendocrine in type may be erroneous.
Silver
M M
MM
Department of Pathology, Hospital for Sick Children, Toronto, Ontario, Canada.
Lines
L D
LD
Hearn
S S
SS
D053379:Chromogranin A; D002864:Chromogranins / Q000032:analysis*; D003594:Cytoplasmic Granules / Q000737:chemistry*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008175:Lung Neoplasms / Q000737:chemistry* / Q000648:ultrastructure; D016253:Microscopy, Immunoelectron; D009490:Neurosecretory Systems / Q000737:chemistry* / Q000648:ultrastructure
C506150:CHGA protein, human; D053379:Chromogranin A; D002864:Chromogranins