Assessment of DNA Ploidy in the ProMisE molecular subgroups of endometrial cancer

We sought to determine whether DNA ploidy correlates with the four molecular subgroups of endometrial carcinoma (EC) as determined using ProMisE (Proactive Molecular Risk Classifier for Endometrial Cancer).

90 cases of EC previously characterized by clinicopathological parameters, outcomes, and ProMisE molecular subgroup (POLE EDM, MMR-D, p53 wt or p53 abn) were assessed for DNA ploidy using image cytometry. Associations of ploidy with traditional clinicopathological parameters were also tested.

Abnormal DNA ploidy status differed amongst the ProMisE groups (p<0.001) and was found in 80.9% (17/21) of p53 abn, 37.0% (10/27) of p53 wt, 28.6% (4/14) of POLE EDM and 14.3% (4/28) of MMR-D. Abnormal DNA content was significantly associated with lower BMI (p=0.034) and grade 3 tumors (p=0.001). In the entire cohort, abnormal DNA content was significantly associated with worse progression free survival (p=0.0094) but not disease specific survival (p=0.249) or overall survival (p=0.187). When examining ploidy within each of the ProMisE groups, abnormal DNA content correlated with worse overall survival (p=0.041) and progression free survival (p=0.011) in the MMR-D group. No statistically significant relationship was seen in the remaining 3 groups.

Abnormal DNA ploidy status did correlate with the molecular subgroups of EC; abnormal DNA content was seen in the large majority of p53 abn cases. Abnormal ploidy however was also seen in smaller numbers in the p53 wt, POLE EDM and MMR-D groups; therefore abnormal DNA content was not a specific marker for any one molecular group. The addition of ploidy to the ProMisE molecular categories conferred additional prognostic value within the MMR-D group, which merits further study.