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
2672 - Changes in clinico-pathological characteristics of vulvar cancer in Japan: increasing oldest-old, stage-shifting, and decreasing cohort-level survival
Presenter: Shin Nishio
Session: Poster Display session 2
Resources:
Abstract
4306 - Tumor Treating Fields (200 kHz) concomitant with weekly paclitaxel for platinum-resistant ovarian cancer: Phase 3 INNOVATE-3/ENGOT-ov50 study
Presenter: Ignace Vergote
Session: Poster Display session 2
Resources:
Abstract
5136 - Randomized, phase 1b/2 study of M6620 + avelumab + carboplatin vs standard care (sc) in patients (pts) with platinum-sensitive poly (ADP-ribose) polymerase inhibitor-(PARPi)-resistant ovarian cancer
Presenter: Susana Banerjee
Session: Poster Display session 2
Resources:
Abstract
2296 - An umbrella study of biomarker-driven targeted therapy in patients with platinum-resistant recurrent ovarian cancer: A Korean Gynecologic Oncology Group study (KGOG 3045), AMBITION
Presenter: Jung-Yun Lee
Session: Poster Display session 2
Resources:
Abstract
2732 - A phase 2 study of pembrolizumab in combination with doxorubicin in advanced, recurrent or metastatic endometrial cancer
Presenter: Ana Oaknin
Session: Poster Display session 2
Resources:
Abstract
4404 - ENGOT-EN9/LEAP-001: a phase 3, randomized, open-label study of pembrolizumab plus lenvatinib versus chemotherapy for first-line treatment of advanced or recurrent endometrial cancer
Presenter: Christian Marth
Session: Poster Display session 2
Resources:
Abstract
4564 - Phase 1/2 trial of tisotumab vedotin plus bevacizumab, pembrolizumab, or carboplatin in recurrent or metastatic cervical cancer (innovaTV 205/ENGOT-cx8)
Presenter: Ignace Vergote
Session: Poster Display session 2
Resources:
Abstract
4933 - Updated data of Epitopes-HPV02 trial and external validation of efficacy of DCF in prospective Epitopes-HPV01 study in advanced anal squamous cell carcinoma. Pooled analysis of 115 patients
Presenter: Stefano Kim
Session: Poster Display session 2
Resources:
Abstract
2301 - Pre-specified pilot analysis of a randomised pilot/phase II/III trial comparing standard dose vs dose-escalated concurrent chemoradiotherapy (CRT) in anal cancer (PLATO-ACT5)
Presenter: Alexandra Gilbert
Session: Poster Display session 2
Resources:
Abstract
5773 - A prospective study of diffusion-weighted magnetic resonance imaging for predicting outcome following chemoradiotherapy, in squamous cell carcinomas of the anus.
Presenter: Rebecca Muirhead
Session: Poster Display session 2
Resources:
Abstract