Counting the number of arginase-1-positive macrophages per area unit (100 × 100 μm) on the tumor slices demonstrated that the average number of M2 macrophages in the ‘Untreated’ group was 40.55 ± 2.93, in the group ‘EVs-CNTR it was a little lower (30.44 ± 3.38), and had dropped down to 7.98 ± 0.74 in tumors from the ‘EVs-Hsp70’ group (Fig. 7b). Here, ARG1 is linked to neoplasm.