HER2 testing on core needle biopsy specimens from primary breast cancers: interobserver reproducibility and concordance with surgically resected specimens

Table 4 Concordance of consensus HER2 judgments by immunohistochemistry between core needle biopsy and corresponding surgically resected specimens.

3 categories (0 or 1+ vs. 2+ vs. 3+)
HER2 score for surgically resected specimens	Number of tumors
	HER2 score for CNB specimens
	0 or 1+	2+	3+
0 or 1+	56	3	1
2+	4	11	0
3+	0	5	20
% agreement = 87%, κ = 0.77, standard deviation (σ) = 0.045
2 categories (0, 1+. or 2+ vs. 3+)
HER2 score for surgically resected specimens	Number of tumors
	HER2 score for CNB specimens
	0, 1+ or 2+		3+
0, 1+, or 2+	74		1
3+	5		20
% agreement = 94%, κ = 0.83, σ = 0.038

ISSN: 1471-2407