RARB and breast cancer: 26). Kim et al., analysing a set of biomarkers (SCGB3A1, RARB, RASSF1 and TWIST1), reported RARB gene methylation in BC patient serum with a sensitivity of 86.6% and a specificity of 93.6%. Adding to this analysis, a second gene, RASSF1, improved the sensitivity to 94.1% and achieved an area under the curve (AUC) of 0.979, although the specificity was lower (88.8%). Nevertheless, the author proposed that these two gene panels are suitable for early and metastatic BC diagnosis (Ref. 30).