The results of GSE148748 (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE148748) showed no significant correlation between IL21R (cg04931655) methylation and tumour size or lymph node involvement in BC (Table S9), which is in agreement with our results as presented in Table 3 and Table S4. Here, IL21R is linked to neoplasm.