Table 3.
Immunohistochemical and molecular phenotypes
| Molecular or immunohistochemical feature | CRC patients < 50 yr of age, n (%) | CRC patients ≥ 50 yr of age, n (%) | P value |
| Microsatellite stability | |||
| Stable | 56 (91.8) | 213 (84.9) | 0.21 |
| Unstabile | 5 (8.2) | 38 (15.1) | |
| NA | 9 | 90 | |
| KRAS mutation | |||
| Negative | 23 (65.7) | 48 (51.1) | 0.17 |
| Positive | 12 (34.3) | 46 (48.9) | |
| NA | 35 | 247 | |
| NRAS mutation | |||
| Negative | 27 (90) | 74 (94.9) | 0.39 |
| Positive | 3 (10) | 4 (5.1) | |
| NA | 40 | 263 | |
| BRAF mutation | |||
| Negative | 29 (90.6) | 87 (86.1) | 0.76 |
| Positive | 3 (9.4) | 14 (13.9) | |
| NA | 38 | 240 | |
| HER 2 | |||
| Negative | 8 (80) | 24 (70.6) | 0.70 |
| Positive | 2 (20) | 10 (29.4) | |
| NA | 60 | 307 |
CRC: Colorectal cancer; NA: Not available.