Independent External Evaluation of an ALTTO-Derived 87-Gene Classifier in HER2-Positive Breast Cancer

Analysis code and derived, de-identified results supporting an independent external evaluation of the fixed ALTTO-derived 87-gene classifier in HER2-positive breast cancer. The archive contains reproducible analysis scripts, a frozen statistical analysis protocol and correction addendum, classifier coefficients, validation logs, data dictionaries, cohort-level and de-identified patient-level derived outputs, bootstrap performance estimates, sensitivity analyses, and decision-curve results. No newly collected clinical specimens or direct personal identifiers are included. Source cohorts are publicly available and are identified in the accompanying documentation and manuscript.