To define the role of the ERp57-STAT3 complex in radioresistance of laryngeal cancer cells, we first checked the expression levels of phosphorylated STAT3 and its target genes, Mcl-1, cyclin D1, and p53 in HEp-2 and RR-HEp-2 cells. This evidence concerns the gene CCND1 and laryngeal carcinoma.