- The staining intensity was divided into three grades (using a scoring system of 0–3): No staining (0), slightly yellowish (1), brownish yellow (2) and dark-brown (3). The multiplications of the two scores were graded as follows: 0 (0 score), 1+ (1–4 score), 2+ (5–8 score) and 3+ (9–12 score). Intensity scores of 0 or 1+ were designated as negative expression, whereas those of 2+ or 3+ were designated as positive expression