An international reproducibility study validating quantitative determination of ERBB2, ESR1, PGR, and MKI67 mRNA in breast cancer using MammaTyper®

Table 1 Intersite reproducibility of centrally (samples 1–8) and locally (samples 9–24) extracted RNA samples as total SD, as well as intersite and residual SD (quantification cycle values)

	Analyte	Intersite		Residual		Total
	Analyte	SD	95% CI	SD	95% CI	SD
RNA pools Samples 1–8	ERBB2	0.16	0.12–0.21	0.24	0.22–0.27	0.29
	ESR1	0.18	0.13–0.29	0.40	0.37–0.44	0.44
	PGR	0.09	0.07–0.13	0.16	0.15–0.17	0.18
	MKI67	0.21	0.17–0.26	0.21	0.19–0.23	0.29
Self-extracted RNAs Samples 9–24	ERBB2	0.22	0.19–0.26	0.23	0.21–0.24	0.31
	ESR1	0.25	0.20–0.31	0.36	0.34–0.39	0.44
	PGR	0.12	0.10–0.16	0.19	0.18–0.20	0.23
	MKI67	0.16	0.14–0.20	0.19	0.18–0.21	0.25
RNA pools and self-extracted RNAs Samples 1–24	ERBB2	0.20	0.17–0.23	0.23	0.22–0.25	0.31
	ESR1	0.22	0.19–0.27	0.38	0.36–0.40	0.44
	PGR	0.11	0.10–0.14	0.18	0.17–0.19	0.21
	MKI67	0.18	0.16–0.21	0.20	0.19–0.21	0.27

Abbreviations: ERBB2 (HER2) Human epidermal growth factor receptor 2, ESR1 (ER) Estrogen receptor, MKI67 Marker of proliferation Ki67, PGR (PgR) Progesterone receptor

ISSN: 1465-542X