NCAPH drives breast cancer progression and identifies a gene signature that predicts luminal a tumour recurrence.

"gene expression data for mouse breast cancers are available from the gene expression omnibus (accession number gse54582)."

"CONFLICT OF INTEREST STATEMENT The authors declare they have no conflicts of interest."

"JPL's laboratory was supported by grant SAF2017‐88854R, funded by MCIN/AEI/10.13039/501100011039 and ‘ERDF: A Way of Making Europe’; grants PID2020‐118527RB‐I00 and PDC2021‐121735‐I00, funded by MCIN/AEI/10.13039/501100011039 and the ‘European Union Next Generation EU/PRTR’, the Carlos III Health Institute (PIE14/00066), the Regional Government of Castile and León (CSI234P18 and CSI144P20) and the ‘We can be heroes’ charity. SCL was supported by grants RTI2018‐094130‐B‐100 and PDI2021‐1246320B‐100, funded by MCIN/AEI/10.13039/501100011039 and ‘ERDF: A Way of Making Europe’. MME, RCC and AJN were funded by fellowships from the Spanish Regional Government of Castile and León. NGS, MJPB and AGC were recipients of an FPU fellowship (MINECO/FEDER). AML was supported by grant RTI2018‐094130‐B‐100, funded by MCIN/AEI/10.13039/501100011039. The HC work was partially supported by the National Cancer Institute at the National Institutes of Health (R01CA184476). JHM was supported by the Department of Defense (DoD) Breast Cancer Research Program (BCRP) Grant No. BC190820. We thank Isabel Ramos and Marina Jiménez for their help with the Animal House Facility and Elena Alonso for technical assistance, and the Pathology Unit of our Center: PMC‐BEOCyL (Departamento de Patología Molecular Comparada—Biobanco en Red de Enfermedades Oncológicas de Castilla y León) for their pathological support. We thank Phil Mason and Mark Sefton for their support with the English language."