Although there were no differences in the LINE-1 methylation levels with regard to ER and HER2 status in DCIS in this study (data not shown) probably due to the smaller sample size, the different proportion of ER-positive or HER2-positive DCIS in the samples may affect the results of LINE-1 methylation levels. The gene discussed is ERBB2; the disease is ductal breast carcinoma in situ.