Abstract 2109
Background
The rates of mismatch repair (MMR) protein deficiency and microsatellite instability (MSI) in ovarian clear cell (CC) and endometrioid (EM) cancer patients were investigated. The clinical features of CC and EM were also analyzed.
Methods
Patients postoperatively diagnosed as CC or EM carcinoma from January 2006 to December 2015 were eligible. Diagnosis of all cases was confirmed by the Central Pathological Review Board. MMR protein was analyzed by IHC using a monoclonal antibody and MSI was examined by a multiplex PCR assay for five microsatellite markers, BAT25, BAT26, NR-21, NR-24, and MONO-27. MLH1 IHC-negative cases were examined for DNA hypermethylation of the MLH1 promoter.
Results
We enrolled 339 cases consisting of 219 CC, 116 EM and 4 mixed type (MT) cases. One case could not be evaluated by IHC. MMR protein deficiency was confirmed in five CC (2.3%), 16 EM (13.9%) and 1 MT case (25%). Deficiency was observed in 4 cases for MLH1 and PMS2, in 13 cases for MSH2 and MSH6, in 1 case for MSH2 and PMS2, in 2 cases for MSH6, and in 1 case for PMS2. DNA hypermethylation of the MLH1 promoter was detected in one of the four MLH1 and PMS2 deficiency cases. Three of the 339 cases could not be evaluated by MSI. A high rate of MSI was confirmed in 13 cases (3.9%) and MMR deficiency was detected by IHC in these cases. However, MSI was not detected in the other nine cases where MMR deficiency was detected by IHC. The median age of all 339 cases was 54 (CC 54, EM 51) and that of CC and EM cases with MMR deficiency was 39 and 48 years, respectively.
Conclusions
The rate of MMR deficiency in CC and EM was not high, whereas CC in young women was more frequent. IHC is a more successful screening method of MMR deficiency in ovarian CC and EM compared with MSI detection. The rate of MLH1 promoter hypermethylation (epigenetic MMR deficiency) in ovarian CC and EM was less than that of endometrial cancer.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The author.
Funding
National Hospital Organization of Japan.
Disclosure
The author has declared no conflicts of interest.
Resources from the same session
2376 - Patient Reported Outcomes (PRO) in patients (pts) with HER2- advanced breast cancer (ABC) and a germline BRCA1/2 mutation (gBRCAm) receiving talazoparib (TALA) vs physician’s choice chemotherapy (PCT) in the EMBRACA trial: A focus on subgroups with/ without visceral disease
Presenter: Johannes Ettl
Session: Poster Display session 2
Resources:
Abstract
4874 - Complete Responses in Patients With 2nd-Line or Greater Metastatic Triple-Negative Breast Cancer (TNBC) Following First-in-Human Immunotherapy Combining NK and T Cell Activation with Off-the-Shelf High-Affinity CD16 NK Cell Line (haNK)
Presenter: Chaitali Nangia
Session: Poster Display session 2
Resources:
Abstract
4362 - Reproducibility and concordance of 4 clinically developed programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) assays in triple-negative breast cancer (TNBC)
Presenter: Aurelia Noske
Session: Poster Display session 2
Resources:
Abstract
4528 - Systemic Therapy in 2nd-Line Metastatic Triple Negative Breast Cancer (mTNBC): A Systematic Literature Review (SLR) and Meta-Analysis (MA) of Efficacy
Presenter: Peter Kaufman
Session: Poster Display session 2
Resources:
Abstract
4112 - Cisplatin given at three divided doses for three consecutive days in metastatic breast cancer: an alternative schedule for one full dose with comparable efficacy but less CINV and hypomagnesaemia
Presenter: Yang Chen
Session: Poster Display session 2
Resources:
Abstract
5699 - Patterns and predictors of first-line (1L) taxane use in US patients with metastatic triple-negative breast cancer (mTNBC)
Presenter: Joyce O’Shaughnessy
Session: Poster Display session 2
Resources:
Abstract
1931 - Maintenance Chemotherapy is effective in Patients with Metastatic Triple Negative Breast Cancer After First-line Platinum-based Chemotherapy
Presenter: Jian Zhang
Session: Poster Display session 2
Resources:
Abstract
4696 - Using the Patient-Reported Outcomes Measurement Information System (PROMIS) to investigate symptom burden enrichment in Stage IV patients at an academic center
Presenter: Madeline Matthys
Session: Poster Display session 2
Resources:
Abstract
4582 - Measures of functional status in adults aged ≥70 years with advanced breast cancer (ABC) receiving palbociclib (PAL) combination therapy in POLARIS
Presenter: Meghan Karuturi
Session: Poster Display session 2
Resources:
Abstract
3565 - Real-World 1-Year Survival Analysis of Patients with Metastatic Breast Cancer with Liver or Lung Metastasis Treated with Eribulin, Gemcitabine or Capecitabine
Presenter: Shayma Kazmi
Session: Poster Display session 2
Resources:
Abstract