Although there are several reports (Chen et al, 2003; Zhou et al, 2006; Huang et al, 2009) that showed the protein or mRNA overexpression of EGFR significantly correlated with ECS in the OSCCs, this is the first study investigating the association between EGFR gene copy number at the primary tumour and the presence of ECS in the metastatic lymph node, and clearly demonstrating the significant correlation between them. The gene discussed is EGFR; the disease is neoplasm.