TABLE 4.

Stratified survival analysis of TCGA.

Variable	Low-risk	High-risk	P-value	HR (95% CI)
Gender
Female	5	6	0.0123	3.806 (0.961–15.08)
Male	21	24	0.0001	3.110 (1.559–6.204)
AJCC stage
I + II	6	12	0.0322	2.534 (0.967–6.640)
III + IV	20	18	0.0006	3.174 (1.444–6.973)
T stage
T1 + T2	12	16	0.0018	2.889 (1.268–6.582)
T3 + T4	14	14	0.0025
N stage
N0	12	21	0.0017	2.823 (1.372–5.806)
N +	14	9	0.0013	3.937 (1.163–13.33)

HR, hazard ratio; CI, confidence interval; AJCC, American Joint Commission on Cancer. *Nineteen patients were not included in the stratified analysis of TCGA dataset, as some clinical information was not available. All P values in bold were less than 0.05 which were considered statistically significant.