Table 4. Association between potential prognostic factors, and RFS and DSS in the validation study of immunohistochemical staining.

Variable	n	RFS			DSS
		Hazed ratio	95%CI	P-value	Hazard ratio	95%CI	P-value
Age (years)
≥45	101	Reference	0.687-2.111	0.515	Reference	0.279-1.441	0.276
<45	26	1.205			0.634
Gender
Male	97	Reference	0.449-1.347	0.369	Reference	0.545-2.020	0.886
Female	30	0.777			1.049
Treatment
Mono-modality*	112	Reference	0.276-1.193	0.137	Reference	0.257-1.506	0.293
Multi-modality**	15	0.574			0.623
pTstage
T1-2	36	Reference	0.655-1.758	0.780	Reference	0.657-2.160	0.564
T3-4	91	1.073			1.191
pNstage
N0-1	45	Reference	1.053-2.970	0.031	Reference	1.064-3.885	0.032
N2-3	82	1.769			2.033
Positive Margin
Absent	107	Reference	0.826-2.702	0.184	Reference	0.848-3.433	0.134
Present	20	1.494			1.707
Extranodal spread of lymph node metastasis
Absent	96	Reference	0.919-2.506	0.103	Reference	0.936-3.266	0.08
Present	31	1.518			1.748
CK4
Negative	87	Reference	0.354-0.988	0.045	Reference	0.159-0.697	0.004
Positive	40	0.591			0.333

NOTE: Analysis uses a multivariate cox regression models for RFS and DSS using variables risk factors including CK4 protein expression. *Surgery alone **Surgery with adjuvant treatment. RFS, relapse-free survival; DSS, disease specific survival; CI, confidential interval; CK4, Cytokeratin 4.