Interpretation of PD-L1 expression
The slides were reviewed and scored independently by two clinical
pathologists specialized in in interpreting PD-L1 expression in solid
tumors. PD-L1 was scored according to the quantity and intensity in the
megakaryocytic lineage of cells. The quantity of PD-L1 expression was
graded from 0 to 100% while the intensity was graded from 1+ to 3+,
according to the level of intensity. The result was a PD-L1 score
calculated by multiplying percentage by intensity of PD-L1 in the bone
marrow megakaryocytes. This score will be detailed further in the
statistical analysis section.