Table 4 Logistic regression analysis of risk factors for low MHC class I expression

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