Similarly, in humanized mice engrafted with human CD34+ cells from donors with v1/v2 SIRPA genotype bearing MDA-MB-231 triple negative breast cancer (TNBC) tumors, AB21 significantly decreased antitumor activity while clone HEF-LB had no impact on tumor growth (Fig. 3b). The gene discussed is CD34; the disease is triple-negative breast carcinoma.