In the MONALEESA-2 trial, consistent PFS benefit was shown independent of PIK3CA, TP53, ZNF703, FGFR1 and ESR1 mutations in the plasma or of CDKN2A, CCND1 and ESR1 mRNA levels or of Rb, Ki67 and p16 protein expression levels in tumor tissue, biopsied before therapy initiation [327]. This evidence concerns the gene ESR1 and neoplasm.