CXCR4 and neoplasm: Further, T22‐PE24‐H6 ArtIBs Ca2+, containing the CXCR4‐targeted cytotoxic polypeptide PE, induced an (p = 0.083) inhibition of tumor growth (n = 3, 1.0 ± 0.2 × 108) stronger than T22‐GFP‐H6 Ca2+ ArtIBs (n = 3, 1.5 ± 0.7 × 108), as compared to the control buffer‐treated group (n = 2, 2.6 ± 1.0 × 108) (Figure 3c).