Table 1: Grading of PD-L1 expression in tumor cells in our institution.

G1

< 1% positive staining viable tumor cells with both complete and incomplete membranous staining at any intensity level

G2

> or = 1-25% positive staining viable tumor cells with both complete and incomplete membranous staining at any intensity level

G3

> or = 25-50% positive staining viable tumor cells with both complete and incomplete membranous staining at any intensity level

G4

> or = 50-75% positive staining viable tumor cells with both complete and incomplete membranous staining at any intensity level

G5

> 75% positive staining viable tumor cells with both complete and incomplete membranous staining at any intensity level