Table 3. Univariate analysis of genetic alterations and clinical characteristics.
| EGFR * | KRAS * | HER2 * | BRAF * | ALK ** | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Characteristics | n (%) | P value | n (%) | P value | n (%) | P value | n (%) | P value | n (%) | P value |
| Age (years) | 0.501 | 0.200 | 0.502 | 0.777 | 0.002 | |||||
| ≤ 65 | 536 (55.0) | 45 (4.6) | 22 (2.3) | 6 (0.6) | 25 (14.0) | |||||
| > 65 | 451 (56.6) | 48 (6.0) | 14 (1.8) | 6 (0.8) | 4 (3.4) | |||||
| Gender | <0.001 | <0.001 | 0.312 | 0.781 | 0.331 | |||||
| Male | 367 (44.7) | 76 (9.3) | 20 (2.4) | 5 (0.6) | 12 (8.0) | |||||
| Female | 620 (65.2) | 17 (1.8) | 16 (1.7) | 7 (0.7) | 17 (11.7) | |||||
| Smoking status | <0.001 | <0.001 | 1.000 | 1.000 | 0.167 | |||||
| Non-smokers | 753 (63.9) | 20 (1.7) | 24 (2.0) | 8 (0.7) | 21 (11.9) | |||||
| Current/former smokers | 234 (39.5) | 73 (12.3) | 12 (2.0) | 4 (0.7) | 8 (6.8) | |||||
| Stage, n (%) # | 0.187 | 1.000 | 0.015 | 0.754 | 0.837 | |||||
| I-IIIa | 298 (58.2) | 27 (5.3) | 4 (0.8) | 4 (0.9) | 10 (10.4) | |||||
| IIIb-IV | 682 (54.6) | 66 (5.3) | 32 (2.6) | 8 (0.6) | 19 (9.6) | |||||
EGFR, epidermal growth factor receptor; ALK, anaplastic lymphoma kinase.
*Cohort 1 (1772 patients with lung adenocarcinoma) testing of EGFR, KRAS, HER2 and BRAF mutations.
**Cohort 2 (295 patients with EGFR-wild type lung adenocarcinoma) testing of EML4-ALK translocation.
#Exclude 12 patients of cohort 1 and 1 patients of cohort 2 with incomplete data on tumor staging For KRAS mutations, a significantly higher mutation rate was noted in male then in female patients (9.3 vs. 1.8%, P < 0.001) and in smokers then in non-smokers (12.3 vs. 1.7%, P < 0.001). Neither age nor tumor stage were correlated with KRAS mutation. For HER2 mutations, patients with more advanced diseases were associated with a higher mutation rate (2.6% in stage IIIb-IV vs. 0.8% in stage I-IIIa, P = 0.015). For BRAF mutation, there was no significant association between patient characteristics and the mutation rate.