In line with these results, we found that SOX2 knockdown decreased the expression of a consistent number of other CSCs markers (BMI1, UBE2C, CD44, NANOG, CXCR4, FAM3C, and RRM2) in both CAL27 and SCC15 3D tumor spheroids (*p-value <0.05) (Fig 5B). The gene discussed is RRM2; the disease is neoplasm.