We applied the Auxin Inducible Degron (AID) proteolytic system, paired with CRISPR/Cas9 knock-in gene-editing, to obtain an unprecedented characterization of the biological activities of Nucleolin (NCL), one of the most abundant nucleolar proteins, in Triple Negative Breast Cancer (TNBC) cells. The gene discussed is AICDA; the disease is triple-negative breast carcinoma.