Prevalence of DNA mutations and variations in protein expression in the 115 HNSCC samples in relation with PFS
| Whole population (n = 115) | Cetuximab in first-line recurrent setting (n = 77) | Cetuximab + radiotherapy (n = 38) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n (%) | Progressiona | HRd | 95% CI (HR) | PFSe | n (%) | Progressiona | HRd | 95% CI (HR) | PFSe | n (%) | Progressiona | HRd | 95% CI (HR) | PFSe | |
| DNA mutations | |||||||||||||||
| PIK3CA | |||||||||||||||
| Mutated | 12 (10.4) | 9 | 1 | 0.30 | 6 (7.8) | 6 | 1 | 0.04 | 6 (15.8) | 3 | 1 | 0.22 | |||
| Wild type | 103 (89.6) | 88 | 1.45 | [0.72; 2.89] | 71 (92.2) | 66 | 0.42 | [0.18; 0.99] | 32 (84.2) | 22 | 2.12 | [0.63; 7.14] | |||
| All RAS | |||||||||||||||
| Mutated | 6 (5.2) | 5 | 1 | 0.96 | 3 (3.9) | 3 | 1 | <0.001 | 3 (7.9) | 2 | 1 | 0.69 | |||
| Wild type | 109 (94.8) | 92 | 1.02 | [0.41; 2.52] | 74 (96.1) | 69 | 0.07 | [0.02; 0.26] | 35 (92.1) | 23 | 1.34 | [0.31; 5.68] | |||
| All mutations | |||||||||||||||
| Mutated | 17b(14.8) | 13 | 1 | 0.23 | 8b(10.4) | 8 | 1 | 0.002 | 9 (23.7) | 5 | 1 | 0.17 | |||
| Wild type | 98 (85.2) | 84 | 1.43 | [0.79; 2.59] | 69 (89.6) | 64 | 0.32 | [0.15; 0.7] | 29 (76.3) | 20 | 1.96 | [0.73; 5.29] | |||
| Level of protein expression | |||||||||||||||
| PTENc | |||||||||||||||
| Low | 7 (6.1) | 7 | 1 | 0.10 | 6 (7.8) | 6 | 1 | 0.71 | 1 (2.6) | 1 | 1 | 0.02 | |||
| High | 107 (93.0) | 89 | 0.52 | [0.24; 1.14] | 71 (92.2) | 66 | 0.85 | [0.37; 1.98] | 36 (94.7) | 23 | 0.12 | [0.01; 1.05] | |||
| EGFR | |||||||||||||||
| Low | 97 (84.3) | 81 | 1 | 0.62 | 63 (81.8) | 60 | 1 | 0.24 | 34 (89.5) | 21 | 1 | 0.08 | |||
| High | 18 (15.7) | 16 | 1.15 | [0.67; 1.97] | 14 (18.2) | 12 | 0.69 | [0.37; 1.29] | 4 (10.5) | 4 | 2.55 | [0.85; 7.64] | |||
Bold values are statistically significant. aProgression data collected until June 2016; bone patient has both PIK3CA and HRAS mutations; cone patient has not been tested; dHR estimated by non-adjusted Cox proportional hazards model; eP-value of the log-rank test. HR, hazard ratio; HNSCC, head and neck squamous cell carcinoma; PFS, progression-free survival.