In this study, factors associated with lower risk of residual LN involvement after NAC included negative ER and PR status, Ki-67 proliferation index > 50%, clinical tumor size \documentclass[12pt]{minimal}\usepackage{amsmath}\usepackage{wasysym}\usepackage{amsfonts}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{mathrsfs}\usepackage{upgreek}\setlength{\oddsidemargin}{-69pt}\begin{document}$$\le $$\end{document}≤ 2 cm, cN0 status, ypT0, and negative pre-NAC LN biopsy as compared to positive pre-NAC LN biopsy. The gene discussed is PGR; the disease is neoplasm.