Abstract 115P
Background
The malignant tumors of female genital system account for most morbidity and mortality among women worldwide. With the increasing knowledge about BRCA mutation in tumors, significant progresses were made in ovarian cancer. But due to poor sensitivity to conventional chemotherapy, effective therapeutic options for endometrial and cervical carcinoma are still unmet clinical needs. Immunotherapy showed remarkable progresses in treatment of melanoma, lung and renal malignancies in recent years. To explore potential use of biomarkers, our study aimed to assess PD-L1 expression on tumor cells and microsatellite instability (MSI) status in Chinese endometrial (EC) and cervical cancer (CC) populations.
Methods
160 endometrial and 197 cervical tumor samples collected in China between January 01, 2017 and April 15, 2020, were analyzed by a College of American Pathologists-certified and Clinical Laboratory Improvement Amendments-accredited lab. PD-L1 expression was accessed by IHC assay (SP263 or 22C3). We scored percentage of PD-L1 expression on tumor cells as TPS: TC3≥50%, TC2≥5% and <50%, TC1≥1% and <5%, and TC0<1%. MSI status was evaluated by targeted next-generation sequencing (NGS) covering 500 MSI loci.
Results
Median age of endometrial cancer patients was 58 years, while cervical cancer patients’ median age was 53 years. 2 (1.2%) individuals had tumors cells PD-L1 scores as TC3, 15 (9.4%) as TC2, 25 (15.6%) as TC1 and 118 (73.8%) as TC0 in EC patients; 16 (8.1%) individuals had tumors cells PD-L1 scores as TC3, 49 (24.9%) as TC2, 40 (20.3%) as TC1 and 92 (46.7%) as TC0 in CC patients. 39 (24.4%) endometrial cancer patients and 8 (4.1%) cervical cancer patients were MSI-H. 17 (43.6%) of MSI-H EC patients and 4 (50%) of MSI-H CC patients were TC1/2/3. TC1/2/3 was associated with MSI-H (P=0.0046) in EC patients, but no association was observed between TC1/2/3 and MSI-H (P=0.848) in CC patients.
Conclusions
The landscape of PD-L1 expression and microsatellite instability status among Chinese endometrial and cervical cancer populations in this study will further assist the utilization of these biomarkers to guide PD-1/PD-L1-related therapeutic strategies.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.