Sections were independently evaluated by two experienced pathologists. Staining intensity was scored using four grades (0 – 3): 0 (negative), 1 (weakly positive), 2 (moderately positive) and 3 (strongly positive). The percentage of positive cells was also scored using five categories (0 – 4): a score of 0 was given for 0 – 5%, 1 for 6 – 25%, 2 for 26 – 50%, 3 for 51 – 75%, and 4 for > 75%. The final staining score was obtained by multiplying the staining intensity and the percentage of positive cells.
