Table 1. Clinicopathological variables of the subjects.
| Variables | HNSCC (n = 273) | Control (n = 122) |
| Age (year) | ||
| Mean ± SD | 53.0±11.0 years | 53.5±13.4 years |
| Range | 27–82 years | 21–85 years |
| Gender (Male : Female) | 251∶22 | 60∶62 |
| Site | ||
| Buccal mucosa | 119 | |
| Tongue | 70 | |
| Gingiva | 45 | |
| Retromolar trigone | 7 | |
| Mouth floor | 7 | |
| Oropharynx | 15 | |
| Hypopharynx | 1 | |
| Lip | 7 | |
| Unspecified | 2 | |
| Tumor size | ||
| T1–T3 | 137 | |
| T4 | 136 | |
| Neck lymph node metastasis | ||
| N (−) | 173 | |
| N (+) | 100 | |
| TNM staging | ||
| Stage I–III | 121 | |
| Stage IV | 152 | |
| Perineural invasion | ||
| (−) | 244 | |
| (+) | 29 | |
| Lymphovascular invasion | ||
| (−) | 246 | |
| (+) | 27 | |
| Follow-up period (Mean ± SD) | 50.4±32.7 months | |
The tumor staging was according to American Joint Committee on Caner (AJCC) TNM staging system. The T represents tumor size and the N represents lymph node metastasis. T1: tumor size less than 2 cm; T2: tumor size between 2 to 4 cm; T3: tumor size larger than 4 cm; T4: tumor invading to adjacent tissues or spaces.