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
3278 - Immune-Related Gene Expression Profiling after Neoadjuvant Chemotherapy (NACT) of Ovarian High-Grade Serous Carcinoma
Presenter: Luis Manso
Session: Poster Display session 2
Resources:
Abstract
4906 - Tumor-infiltrating lymphocytes (TILs) in patients with epithelial ovarian cancer undergoing neoadjuvant chemotherapy: A restrospective study
Presenter: Sara Giovannoni
Session: Poster Display session 2
Resources:
Abstract
3919 - Prognostic significance of elements of the adaptive immunity in the microenvironment of epithelial ovarian cancer.
Presenter: Periklis Foukas
Session: Poster Display session 2
Resources:
Abstract
5139 - Neutrophil-to-lymphocyte ratio predicts platinum sensitivity in epithelial ovarian cancer patients: a MITO24 retrospective study
Presenter: Alberto Farolfi
Session: Poster Display session 2
Resources:
Abstract
4212 - The prognostic impact of monocyte to lymphocyte ratio (MLR) in advanced epithelial ovarian cancer (EOC)
Presenter: Marc Cucurull Salamero
Session: Poster Display session 2
Resources:
Abstract
5123 - TP53 Hotspot mutations as immunoreactive neoantigens define a signature with differential survival outcomes in advanced ovarian cancer
Presenter: Marica Garziera
Session: Poster Display session 2
Resources:
Abstract
3795 - Use of bevacizumab (Bev) in real life for first-line (fl) treatment of ovarian cancer (OC)/ The GINECO ENCOURAGE cohort of 500 French patients
Presenter: Dominique Berton-Rigaud
Session: Poster Display session 2
Resources:
Abstract
2359 - Phase II study: Letrozole maintenance therapy after first line chemotherapy in patients with advanced serous and endometrioid ovarian cancer
Presenter: Alexandra Tyulyandina
Session: Poster Display session 2
Resources:
Abstract
3619 - Baseline IPI (Immune Prognostic Index) predicts survival in patients with advanced cervical cancer treated with immune checkpoint inhibitors (ICI).
Presenter: Felix Blanc-Durand
Session: Poster Display session 2
Resources:
Abstract
3474 - Preselecting tumor-infiltrating lymphocyte subsets to implement adoptive inmmunotherapy in ovarian cancer
Presenter: Diego Salas-Benito
Session: Poster Display session 2
Resources:
Abstract