MKI67 and neoplasm: Response was defined as a decrease in IHC staining for MKI67 when comparing pre‐ vs posttreatment EC tissue as previously described.4 Quantitative LC‐MS/MS‐based global proteomic analyses of pathologically defined tumor cell populations harvested by LMD from FFPE endometrial biopsies and EC surgical tumor tissues identified 1289 proteins by at least two PSMs across patients (Table S1 and S2).