Fig. 1.

Project overview. Samples were split into a discovery cohort and a validation cohort. The discovery cohort was analyzed with the Illumina HT12 v4 whole transcriptome microarray. Top discriminating genes for ipsilateral breast tumor recurrence were combined with genes from the literature and previous signatures for a radiosensitivity gene panel. A targeted assay was developed, and both the discovery cohort and the validation cohort were analyzed. Single-sample predictors were developed in the discovery cohort and validated in the validation cohort and in public datasets. Finally, the previously published signatures were tested in all our data. ER, estrogen receptor; RT, adjuvant radiotherapy