ABCG2 and neoplasm: Imai et al. [83] observed that CD271+ tumor cells increased from 16.3% to 35.2% post-cisplatin treatment, demonstrating marked cisplatin resistance mediated by upregulation of ABC transporter expression, specifically ABCC2 (2.5-fold), ABCB5 (4.8-fold), and ABCG2 (2.4-fold), establishing a mechanistic association between this CSC subpopulation and active drug efflux-mediated resistance.