Data associated with the figures presented in this study are images, graphics, or tabulated data based on histopathologic analysis performed by a certified study pathologist or image analysis. Data for Tables 1 and 2 provide incidence, labeling scores, and p-values for statistical tests for uterine pathology and IHC expression by treatment group and timepoint or human endometrial tissue, as described in the Main Text file of the manuscript. Manual histopathologic data can be found in excel spreadsheets and are based on presence/absences (yes/no) of a pathologic finding and/or severity score as described in the manuscript (Fig. 1, 2, 3, 4). The image analysis data is based on the quantified area that is designated as “positive” for a particular immunohistochemical stain (Fig. 2, 4, and Suppl. Fig. S2). Supplementary Table 1 provides summary information on antibodies used for immunohistochemistry. Supplementary fig. S1 includes real time RT-PCR data standardized to a housekeeping gene and western blot data. This dataset is associated with the following publication: Suen, A., W. Jefferson, C. Wood, and C. Williams. SIX1 regulates aberrant endometrial epithelial cell differentiation and cancer trajectory. Molecular Cancer Research. American Association for Cancer Research, Inc., Philadelphia, PA, USA, 17(12): 2369-2382, (2019).