Abubakar M, Zhang J, Ahearn TU, et al. - This study was carried out to assess whether tumor-associated stromal cellular density as a predictor of recurrence and mortality in breast cancer. Researchers defined tumor-associated stromal cellular density (SCD) as the percentage of tumor–stroma that is occupied by nucleated cells by applying machine learning to digitized hematoxylin and eosin (H&E)-stained sections for 2,084 breast cancer patients from China (n = 596; 24–55 years), Poland (n = 810; 31–75 years), and the United States (n = 678; 55–78 years). They estimated Hazard ratios and 95% confidence intervals for associations between SCD and clinical outcomes [recurrence (China) and mortality (Poland and the United States)] using Cox proportional hazard regression, adjusted for clinical variables.The data suggest the independent prognostic value of tumor-associated SCD among ethnically diverse luminal breast cancer patients.