Table 4.

Logistic regression analysis of risk factors for low MHC class I expression

Factors	Univariate analysis		Multivariate analysis
	OR (95% CI)	p-value	OR (95% CI)	p-value
Age at diagnosis (≥ 60)	0.60 (0.37–0.98)	0.042	0.99 (0.54–1.85)	0.998
Gender (female)	0.72 (0.44–1.17)	0.187
Primary tumor site		0.136
Left colon	0.79 (0.41–1.50)	0.464
Right colon	1.36 (0.74–2.50)	0.323
Rectum (reference)	–	–
Stage (7th AJCC)		0.245
I	0.47 (0.17–1.35)	0.161
II	0.38 (0.15–0.97)	0.044
III	0.43 (0.16–1.17)	0.097
IV (reference)	–	–
Tumor stage		0.005		0.122
T1	0.89 (0.27–2.99)	0.849	6.78 (0.97–47.42)	0.054
T2	0.37 (0.16–0.86)	0.02	0.91 (0.22–3.72)	0.897
T3	0.35 (0.19–0.65)	0.001	0.71 (0.33–1.52)	0.377
T4 (reference)	–	–	–	–
Node stage (positive)	0.92 (0.54–1.56)	0.753
Negative lymph nodes (high)	1.42 (0.89–2.28)	0.143
Tumor histological grade		0.004		0.117
Well-differentiated	0.00	0.999	0.00	0.999
Moderately differentiated	0.38 (0.22–0.65)	< 0.001	0.47 (0.23–0.94)	0.034
Poorly differentiated	0.76 (0.38–1.52)	0.436	0.99 (0.42–2.38)	0.989
Mucinous (reference)	–	–	–	–
Nerve invasion (no)	1.66 (0.73–3.77)	0.227
Vascular invasion (no)	1.10 (0.51–2.38)	0.814
MMR status (dMMR)	15.16 (7.81–29.42)	< 0.001	15.34 (7.24–32.50)	< 0.001
CD3 expression (high)	0.91 (0.54–1.52)	0.714
CD4 expression (high)	0.57 (0.35–0.93)	0.025	1.05 (0.57–1.96)	0.871
CD8 expression (high)	1.42 (0.83–2.42)	0.198
CD56 expression (high)	0.49 (0.30–0.79)	0.004	0.92 (0.50–1.70)	0.795
PD-1 expression (high)	0.95 (0.56–1.61)	0.855
PD-L1 expression (positive)	0.70 (0.43–1.12)	0.133

OR: odds ratio; 95% CI: 95% confidence interval

Only the meaningful factors (p < 0.05) in univariate analysis were brought into the multivariate analysis