Table 1.

Standards and scores of IHC staining.

Intensity score		Percentage score		Staining score=(1)×(2)
Score	Criteria	Score	Criteria	Score	Description
0	No staining	0	No positive cell	0	Negative (−)
1	Light yellow	1	0~25% positive cells	1~3	Weak positive (+)
2	Brown yellow	2	26~50% positive cells	4~5	Moderate (++)
3	Dark brown	3	51~75% positive cells	6~7	Strong (+++)
		4	>75% positive cells