We established a mouse subcutaneous tumor model by subcutaneous injection of MDA-MB-231 cells, and used exosome-deleted SNHG12 (named as Exo-SNHG12 KD) and corresponding negative control exosome (Exo-SNHG12 KD-MOCK) to treat the mice. The gene discussed is SNHG12; the disease is neoplasm.