CD44 and breast cancer: This study demonstrated a higher plasma HMGA2 levels in high grade BC patients than in low grade BC patients, as studies have shown an important role for the HMGA2 protein in promoting the expression of cancer stem cell markers, especially CD44, Oct4, c-Myc, ALDH1, and Twist1 (Mansoori et al. 2020, 2021a; Sun et al. 2017), additionally to the activation of the Wnt/β-catenin pathway, which is known to be responsible for self-renewal, further promoting cancer cell aggressiveness, metastasis, and resistance to cancer therapies (Zha et al. 2013).