SOX2 and cancer: Similarly, overexpression of circFOXK2‐WT could increase MTCO1 expression, complex IV activity, OCR, mtROS, cancer stemness, cisplatin resistance, and SOX2 expression levels in T24‐CIS cells, but circFOXK2‐MUT could not (Figure 7A–C; Figure S9C–H, Supporting Information).