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
4732 - Progesterone Receptor Isoform Ratio Dictates Antiprogestins/Progestins Effects on Metastatic Breast Cancer Models
Presenter: Maria Abascal
Session: Poster Display session 2
Resources:
Abstract
5737 - PAM50 and CGH-array genomic characterization of HER2-Equivocal Breast Cancers defined by the 2018 ASCO/CAP recommendations.
Presenter: Carine Ngo
Session: Poster Display session 2
Resources:
Abstract
1096 - OncotypeDX® predictive nomogram for recurrence score output: a machine learning system based on quantitative immunochemistry analysis - ADAPTED01
Presenter: Fabio Marazzi
Session: Poster Display session 2
Resources:
Abstract
5426 - Geriatric parameters predict both disease-related and patient-reported outcomes in older patients with breast cancer
Presenter: Willeke van der Plas-Krijgsman
Session: Poster Display session 2
Resources:
Abstract
5865 - Patients with a 21-gene assay in South East London differ from the TAILORx trial population
Presenter: Charalampos Gousis
Session: Poster Display session 2
Resources:
Abstract
1312 - Predictive tools in adjuvant breast cancer – what is the standard of evidence supporting their utility? A literature review examining validation of Adjuvant!, Cancermath and NHS Predict
Presenter: Alice Loft
Session: Poster Display session 2
Resources:
Abstract
2445 - Oncologic outcome of invasive lobular carcinoma: Is it different from that of invasive ductal carcinoma?
Presenter: Hee Jun Choi
Session: Poster Display session 2
Resources:
Abstract
2476 - Pathologic response and survival efficacy in patients with initial nodal involvement after neoadjuvant chemotherapy in early breast cancer
Presenter: SERAFIN MORALES Murillo
Session: Poster Display session 2
Resources:
Abstract
3761 - Chemotherapy-induced amenorrhea: prognostic impact on premenopausal Egyptian patients with breast cancer
Presenter: Khaled Abdel Karim
Session: Poster Display session 2
Resources:
Abstract
4687 - Predicting the presence of breast cancer using circulating small RNA in the serum
Presenter: Yumiko Koi
Session: Poster Display session 2
Resources:
Abstract