Similarly, a metastatic gastric cancer cell line, AZ-P7a cells selectively secrete let-7 family miRNAs, which are considered mainly as tumor suppressor genes targeting oncogenes such as RAS and high-mobility group A2 (HMGA2), into the extracellular environment via exosomes to maintain their tumorigenic and metastatic propensities [21]. The gene discussed is HMGA2; the disease is neoplasm.