library_construction_protocol: RNA was extracted with Trizol reagent, followed by clean-up and DNase I treatment with QIAGEN RNeasy mini kit in accordance with the prescribed protocol provided with the kit. Genomic DNAs were extracted from the mammary tumors of mice offspring using DNeasy Blood and Tissue Kit (Qiagen). Quality control was performed with Agilent Bioanalyser. RNA libraries or bisulfite-converted DNA libraries were prepared for sequencing using standard Illumina protocols.