Overall, the higher median VAF was associated with higher tumor grade (p = 0.0463), the presence of more than one plasma mutation in plasma with the likelihood of clinical relapse (p = 0.0237) and TP53 mutations in plasma more frequently observed in hormone receptor (HR)-negative tumors (estrogen receptor (ER)-negative p = 0.0316; progesterone (PR)-negative, p = 0.0257). The gene discussed is ESR1; the disease is neoplasm.