| Marker | Atypical small cells | Squamous component and a few basaloid nests |
| 34βE12 | - | + |
| p63 | - | + |
| chromogranin A | + | - |
| synaptophysin | + | - |
| CD56 | + | - |
| CEA | - | - |
| p16 | + | + |