Table 2 Clinical features of primary mammary tumours collected from Mmtv-Pymt mice that met the inclusion criteria for the study. Mammary tumours were collected from Mmtv-Pymt transgenic mice at either estrus or diestrus phase of the ovarian cycle. Ovarian cycle stage was determined by cytological analysis of vaginal smears, performed for at least 2 weeks. All tumours are estrogen receptor positive as determined through immunohistochemistry. No differences in tumour features were observed between ovarian cycle stages

From: Ovarian cycle stage critically affects 21-gene recurrence scores in Mmtv-Pymt mouse mammary tumours