Immunocytochemistry
![ICC 1](https://dlmp.uw.edu/content/page-img/361/spa-img0055__small.jpg)
Hematoxylin and eosin (H&E)-stained section of a poorly differentiated tumor found in brain biopsy. The polygonal shape of the cells and their cohesion suggest an epithelial tumor (i.e. a carcinoma).
![ICC 2](https://dlmp.uw.edu/content/page-img/361/spa-img0056__small.jpg)
Immunocytochemical study of same tumor as in slide 1 using monoclonal antibody to low molecular weight cytokeratin using antibody 35ßH11, showing a complete absence of reactivity.
![ICC 3](https://dlmp.uw.edu/content/page-img/361/spa-img0057__small.jpg)
Immunocytochemical study of same tumor as in slide 1 using monoclonal antibody HMB45 to melanoma. Positive antibody binding is indicated by the black reaction product. This result indicates that the tumor is a variant of a melanoma, not a carcinoma.
![ICC 4](https://dlmp.uw.edu/content/page-img/361/spa-img0058__small.jpg)
Summary of antibody studies useful in determining site of origin of carcinomas presenting at metastatic sites.
![ICC 5](https://dlmp.uw.edu/content/page-img/361/spa-img0059__small.jpg)
Hematoxylin and eosin (H&E)-stained section of tumor in supraclavicular lymph node found in 72 year old male. It is not obvious where this poorly differentiated carcinoma metastasized from.
![ICC 6](https://dlmp.uw.edu/content/page-img/361/spa-img0060__small.jpg)
Immunocytochemical study of same tumor cells as in slide 5 employing antibodies to prostatic specific antigen, showing positive reaction, and pointing to site of origin of tumor in prostate.