CD44 and cancer: We found that the phosphorylation of AKT, a downstream effector of the CD44 pathway identified in several types of cancer cells [33,34,35], were elevated in MRE11-overexpressing CAL-27 and Ca9-22 cells transfected with scramble siRNA, whereas these phenomena were reversed in the counterpart MRE11-overexpressing OSCC cells transfected with siRNA that targets CD44 (Figure 3A and Supplementary Figure S3A, respectively).