Table 6. Correlation of microarray–based expression profiling data with routinely established PR status.

		Total	PR status defined by predictor	Clinical PR status
				Negative	Positive	p-value*
Training	GSE3494	251	Negative	45	31	2.3·10−16
			Positive	16	159
	GSE3494**	251	Negative	29	17	<3.3·10−10
			Positive	32	173
Validation	GSE20271	144	Negative	63	15	6.1·10−12
			Positive	16	50
	GSE20194	278	Negative	107	22	<2.2·10−16
			Positive	50	99
	GSE9195	79	Negative	9	24	0.1484
			Positive	6	40

*Fisher's exact test.

**The analysis was performed by using the “best probe set” (“219197_s_at”). The rest of analyses were performed by using the 51-gene PR signature.