Katherine Fraser¹ , Joanne Moses¹

¹Department of Anatomical Pathology, LabPlus, Auckland, New Zealand

 

Background:
Endometrial cancer (EC) is the most common gynaecological malignancy in New Zealand1. The Cancer Genome Atlas has identified four molecular subgroups of EC, each with distinct prognostic and therapeutic implications: POLE-ultramutated, mismatch repair-deficient (dMMR), p53-mutant (p53abn), and no specific molecular profile (NSMP)2. Targeted POLE sequencing has recently been implemented in Northern and Midland Gynaecological Services in selected high-grade EC.

Objective:
This audit evaluates the first 70 cases of EC sent for targeted molecular analysis to assess the prevalence of molecular subgroups and selected pathological correlations.

Methods:
We identified the first 70 EC cases (01/2023–09/2024) sequenced using the SONIC FIND-IT endometrial panel, which covers  POLE, TP53, PIK3CA, and CTNNB1 mutations. We then collected and analysed selected clinicopathological and molecular data.

Results:
Of the 70 cases, 13% were POLE-mutated, 31% dMMR, 40% p53-abnormal, and 13% NSMP. Thirteen percent had multiple molecular classifiers, with p53 as the second classifier in all cases. Nine cases showed discordance between p53 immunohistochemistry and TP53 sequencing.

Conclusion:
This audit highlights the promising integration of molecular classification in Northern and Midland regions of New Zealand and emphasizes the need to address discordances between IHC and sequencing results for more accurate EC diagnostics.

Statement of originality
My role in this audit was to collect and analyse the data from each case. As trends emerged, I added additional data points. I summarized the results and contributed to the conclusions. I also designed and developed the poster with supervision and guidance from Dr. Joanne Moses.