Table 2. Classification performance of the discovery, independent replication and serum studies.

Studies	Accuracy	Specificity	Sensitivity	Negative Predictive Value	Positive Predictive Value	P-value*
41-miRNA model performance in breast tissue
Discovery	0.833	0.840	0.800	0.954	0.500	-
Replication	0.634	0.771	0.348	0.711	0.421	0.090
20-miRNA*** model performance in breast tissue and serum
Discovery	0.811	0.813	0.800	0.953	0.461	-
Serum (GSE44281)	0.532	0.746	0.317	-	-	0.064

* P-value testing the performance of miRNA model based on 10,000 random permutations.

***Only 20 out of 41-miRNA were profiled and detected above background level in serum samples.