Concerning the methylation of macromolecules, it is interesting to note that HSD17B4 methylation was identified as a predictive response marker to HER2-directed therapy in ERBB2+ BCa [31] and that genes involved in cancer-related pathways were frequently affected by epigenetic alterations in HER2-positive breast cancer [32]. This evidence concerns the gene HSD17B4 and breast carcinoma.