Table 2.
Correlation of immunohistochemical and molecular biomarkers with survival in skull base chordomas. Of the biomarkers studied, Ki67 PI 5% and 9p LOH were significantly associated with shorter overall survival (OS), while chordomas with 9p21 homozygous deletion trended toward shortened OS. P53 accumulation, EGFR expression, and deletions on 1p, 10q, and 17p were not significantly associated with survival.
| Biomarker | Result | Frequency (%) | Mean OS (mos) | 95% CI (mos) | P |
|---|---|---|---|---|---|
| Ki67 PI | <5% | 17/25 (68) | 159.3 | 118.9 – 199.7 | 0.005 |
| ≥5% | 8/25 (32) | 69.3 | 28.7 – 110.0 | ||
| P53 expression score | <25 | 14/25 (56) | 145.1 | 102.3 – 187.9 | 0.282 |
| ≥25 | 11/25 (44) | 96.6 | 65.4 – 127.8 | ||
| EGFR expression | negative | 22/24 (92) | 137.6 | 99.1 – 176.1 | 0.270 |
| positive | 2/24 (8) | 57.7 | 16.4 – 98.9 | ||
| 1p36 FISH | intact | 19/23 (83) | 134.5 | 97.2 – 171.7 | 0.628 |
| hemizygous deletion | 4/23 (17) | 122.7 | 91.7 – 153.6 | ||
| 1p LOH | negative | 15/24 (62) | 142.0 | 91.0 – 192.9 | 0.820 |
| positive | 9/24 (38) | 120.4 | 87.5 – 153.2 | ||
| 9p21 FISH | intact | 18/23 (78) | 151.4 | 115.1 – 187.7 | 0.083 |
| homozygous deletion | 5/23 (22) | 73.8 | 47.9 – 99.7 | ||
| 9p LOH | negative | 22/25 (88) | 146.2 | 109.8 – 182.5 | 0.033 |
| positive | 3/25 (12) | 71.7 | 42.5 – 100.9 | ||
| 10q LOH | negative | 9/21 (43) | 130.7 | 75.8 – 185.6 | 0.855 |
| positive | 12/21 (57) | 117.1 | 83.3 – 150.9 | ||
| 17p LOH | negative | 11/23 (48) | 120.4 | 69.2 – 171.6 | 0.565 |
| positive | 12/23 (52) | 125.1 | 92.9 – 157.3 |
CI = confidence interval.