To further examine the effect of WHSC1L1-mediated EGFR K721 mono-methylation on endogenous phospho-Y1148 and phospho-Y1173 EGFR marks in SCCHN cell lines, we performed siRNA-mediated knockdown of WHSC1L1 with two different WHSC1L1-specific siRNAs in two SCCHN cell lines, YD-10B and HN13, which endogenously overexpress wild-type WHSC1L1 and EGFR. The gene discussed is EGFR; the disease is head and neck squamous cell carcinoma.