Table 2.
Panel of Routine Immunohistochemical Markers for the Evaluation of Suspected Anaplastic Thyroid Cancer and Expected Results Compared with Other Tumor Types
| IHC marker | DTC | PDTC | ATC | MTC | SCC | Lymphoma |
|---|---|---|---|---|---|---|
| Pan-cytokeratins | +++ | +++ | +++/− | +++ | +++ | − |
| Thyroglobulin | +++ | +/− | − | − | − | − |
| Thyroid-transcription factor 1 | +++ | +/− | −/+ | +/− | − | − |
| BRAFV600E | +/− | −/+ | −/+ | − | − | − |
| PAX8 | +++ | +++ | +/− | +/− | − | +/−a |
| Ki-67b | <5% | 5–30% | >30% | <20% | >30% | variable |
| Chromogranin | − | − | − | +++ | − | − |
| Calcitonin | − | − | − | +++/− | − | − |
| Carcinoembryonic antigen | − | − | − | +++ | − | − |
| p53 | − (rare +) | −/+ | +/− | − | +/− | +/− |
| CD45, other lymphoid markers | − | − | − | − | − | +++ |
+ indicates relative positive staining, − indicates negative staining, +/− indicates variable positivity.
a
PAX8 antibodies can cross-react with PAX5, which is expressed in lymphoid cells.
b
Percentage of nuclei positive for Ki-67.
DTC, differentiated thyroid cancer; IHC, immunohistochemistry; MTC, medullary thyroid cancer; PDTC, poorly differentiated thyroid cancer.