Table 2 Expression and agreement statistics (κ coefficient) of PD-L1, B7-H3, B7-H4, IDO1, and EphA2 in primary NSCLC and its brain metastases

PD-L1 Positive

PD-L1 Negative

Lung:

PD-L1 Positive

2

2

0.61

0.007

PD-L1 Negative

0

13

B7-H3 high expression

B7-H3 low expression

B7-H3 high expression

6

1

0.43

0.059

B7-H3 low expression

4

6

B7-H4 high expression

B7-H4 low expression

B7-H4 high expression

7

1

0.53

0.024

B7-H4 low expression

3

6

IDO1 high expression

IDO1 low expression

IDO1 high expression

4

2

0.38

0.115

IDO1 low expression

3

8

EphA2 high expression

EphA2 low expression

EphA2 high expression

3

3

-0.04

0.858

EphA2 low expression

6

5