Table 1.
Immunohistochemistry (IHC) markers and immunohistochemical characteristics of SCLC.
| Marker | Stain | Comments |
|---|---|---|
| Keratin (MWlow) | + | Paranuclear/Cytoplasmatic diffuse |
| Keratin (MWhigh) | - | Not expressed in SCLC |
| Ki67 | + | At high levels, hallmark of SCLC vs NE tumors |
| NCAM/CD56 | + | Variable/Lower compared to other NE tumors |
| Chromogranin | + | Variable/Lower compared to other NE tumors |
| Synaptophysin | + | Variable/Lower compared to other NE tumors |
| INSM1 | + | Variable/Lower compared to other NE tumors |
| Napsin A | - | Presence of this marker favors LCNEC diagnosis |
| TTF-1 | + | Useful SCLC diagnosis vs NE tumors not originated in the lung |
| BCL-2 | + | Often expressed in SCLC |
| P16 | + | Expressed in >95% of SCLC |
| CD117/KIT | + | Expressed in 60% of SCLC |
| P-RB | - | Never expressed in SCLC |
| OTP | - | Never expressed in SCLC |