Abstract
PIK3CA mutations are common in HR+/HER2− metastatic breast cancer and guide the use of PI3K-targeted therapies. This expert consensus provides recommendations on timing, methods, and interpretation of PIK3CA testing, emphasizing early assessment at metastatic diagnosis, preferred use of NGS panels, and standardized pre-analytical workflows. Reflex and dual-sample strategies can reduce delays and failures. Implementation requires coordinated logistics, education across the diagnostic chain, and equitable access to ensure timely, personalized treatment.
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The authors thank Ánchel González Barriga and Blanca Piedrafita from Medical Science Consulting (Spain) for providing editorial support, including medical writing and assembling tables/figures based on the authors’ detailed directions, collating author comments, copyediting, fact-checking, and referencing. The study was funded by Roche.
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C.M. has received personal consultancy fees from Menarini, Roche, and Illumina, and speaker fees from Daiichi Sankyo and Veracyte, outside the submitted work. F.R. reports honoraria and participation in advisory boards/consultation for AstraZeneca, Eli Lilly, Menarini Stemline, Novartis, Pfizer, MSD, Merck, Amgen, Janssen, Bristol Myers Squibb (BMS), Astellas, AbbVie, BeiGene, SOPHiA GENETICS, Agilent, and Roche; and research funding from Pfizer, Astellas, Menarini Stemline, and AstraZeneca. E.R.C. reports honoraria from AstraZeneca, Eli Lilly, Guardant, Menarini Stemline, Novartis, Pfizer, and Roche; participation in advisory boards/consultation for AstraZeneca, Eli Lilly, NanoString, Pfizer, and Roche; conference fees/travel/accommodation from Roche and Novartis; an educational grant from Daiichi Sankyo; and research support from SECA. B.B. reports honoraria and participation in advisory boards/consultation for AstraZeneca, Incyte, Menarini Stemline, Novartis, MSD, Merck, Amgen, Johnson & Johnson, BMS, Pfizer, Thermo Fisher, and Roche; and research funding from Roche, Thermo Fisher, and AstraZeneca. C.F. has received honoraria and/or fees from Pfizer, Roche, Eisai, AstraZeneca, Eli Lilly, MSD, Novartis, Gilead, and Veracyte. F.S. declares no competing interests. C.M. and F.S. are Associate Editors of npj Breast Cancer. C.M. and F.S. were not involved in the journal’s review of, or decisions related to, this manuscript.
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Marchiò, C., Rojo, F., Copson, E.R. et al. Expert recommendations for PIK3CA testing in HR+/HER2− locally advanced and metastatic breast cancer. npj Breast Cancer (2026). https://doi.org/10.1038/s41523-026-00968-3
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DOI: https://doi.org/10.1038/s41523-026-00968-3
