Prognostic Significance of Young Age (<35 Years) by Subtype Based on ER, PR, and HER2 Status in Breast Cancer: A Nationwide Registry‐Based Study

The prognostic significance of young age was found to depend on molecular subtype. An age of <35 years was a poor prognosticator in patients with the HR+/HER2-, HR+/HER2+, and HR-/HER2+ subtypes, but not in those with the TN subtype.