XRCC1 and osteosarcoma: Other genes specifically down-regulated in EOC-CC1 cells after FOXM1 inhibition were those coding for (i) the centrosomal protein CEP55, recently identified as an indicator of malignant conversion and progression in head-and-neck squamous cell carcinoma [44] and (ii) the DNA repair gene XRCC1, whose transcriptional regulation by FOXM1 has been demonstrated in osteosarcoma U2OS cells [45].