SLC25A21 and neoplasm: Furthermore, in vitro, SLC25A21 knockdown promoted BC cell proliferation while inhibiting cell apoptosis [127]. Conversely, it has been observed that SLC25A21-AS1 expression was reported to be upregulated in cisplatin-resistant nasopharyngeal cells (NPC) and that SLC25A21 knockdown showed more effective tumor size and weight suppression with cisplatin treatment, implying that bringing down SLC25A21-AS1 inhibited NPC cellular proliferation and multi-drug resistance in vitro and in vivo [128].