Abstract 1234
Background
Gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC) is a poorly differentiated grade 3 neuroendocrine neoplasm, of which the overall survival is poor with limited treatment options. Immune checkpoint related therapy such as PD-1 blocking has successfully been used in some solid tumor treatment. In this study, we investigated the infiltration of immune-cells and PD-1/PD-L1 blockade biomarkers to improve understanding of the tumor immune microenvironment in GEP-NEC.
Methods
Stromal and tumor cells expressing CD3, CD8 and CD68 protein were assessed in 32 cases of GEP-NEC by immunohistochemistry. Their tumor mutational burden (TMB) and microsatellite instability (MSI) were measured by gene sequencing. Software mSINGS MSIsensor and MSIseq were used to evaluate MSI and MSI status was set when more than two software showed the MSI. The Mann-Whitney U test and Kruskal-Wallis test were used to analyze the correlation of markers expression with clinicopathological parameters. Kaplan -Meier curves were applied in survival analyses.
Results
In the study, 65.6% of the patients were male and the median age was 65. The predominant primary sites were stomach (66%) and pancreas (19%). High infiltration (more than 25% stromal area infiltration) of CD3, CD8 and CD68 immune cells were found in 84%, 47% and 81% of the patients, respectively. High expression of CD3 correlated with high expression of CD8 and CD68 (p < 0.05). Average of TMB was 5.84 mutations per megabase. 57% of the patients were classified as having intermediate TMB (5-15 mutations/megabase) with the remaining classified as having low TMB (0-5 mutations/megabase). None of the patients was in MSI status under our evaluation. Among the baseline characteristics, patients in stage IV of TNM showed lower CD8 expression (p < 0.05). No significant association was observed between the investigated markers and survival.
Conclusions
The study contributes to the understanding of immune microenvironment of GEP-NEC. The association of clinicopathological features with PD-1/PD-L1 blockade biomarkers and immune cells in GEP-NEC were explored. This understanding should help to improve predictions of the impact of the PD-1/PD-L1 pathway in GEP-NEC patients.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Chinese Academy of Medical Sciences (CAMS) Initiative for innovative Medicine (CAMS-I2M) 2017-I2M-1-001.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
3780 - Perioperative atezolizumab in combination with FLOT versus FLOT alone in patients with resectable esophagogastric adenocarcinoma: DANTE, a randomized, open-label phase II trial of the German Gastric Group of the AIO and the SAKK.
Presenter: Salah-Eddin Al-Batran
Session: Poster Display session 2
Resources:
Abstract
3006 - Nal-iri/lv5-fu versus paclitaxel as second-line therapy in patients with metastatic esophageal squamous cell carcinoma (OESIRI-PRODIGE 62): A FFCD multicenter, randomized, phase II study.
Presenter: Violaine Randrian
Session: Poster Display session 2
Resources:
Abstract
3697 - The expression of Versican and its role in pancreatic neuroendocrine tumor
Presenter: Zhao Sun
Session: Poster Display session 2
Resources:
Abstract
6073 - Characteristics of patients with thyroid carcinoma in the united states
Presenter: Dina El-Habashy
Session: Poster Display session 2
Resources:
Abstract
2124 - The discrimination of pituitary adenomas and craniopharyngioma on MRI: from image features to texture features
Presenter: Hanyue Xu
Session: Poster Display session 2
Resources:
Abstract
3786 - Proportion of Peripheral Lymphocyte Subsets Correlates with the Progression-free Survival and Metastatic Status of Pancreatic Neuroendocrine Tumor Patients
Presenter: Yitao Gong
Session: Poster Display session 2
Resources:
Abstract
2263 - Immunohistochemical expression of ER-α and PR in papillary thyroid carcinoma
Presenter: Enas Elkhouly
Session: Poster Display session 2
Resources:
Abstract
4386 - SILVELUL Project: Immunohistochemical panel analyses as potential predictive and prognostic factors in Pancreatic Neuroendocrine Tumors (PanNET) Treated with CAPTEM or Everolimus
Presenter: Ana De Jesus-Acosta
Session: Poster Display session 2
Resources:
Abstract
2302 - Carcinoid heart disease (CHD): the CRUSOE-NETs, a prospective cohort study from the French Group of Endocrine Tumors (GTE)
Presenter: Kathleen Dekeister Geoffroy
Session: Poster Display session 2
Resources:
Abstract
5749 - Safety of high doses of somatostatin analogs in well differentiated NENs in elderly
Presenter: Massimiliano Cani
Session: Poster Display session 2
Resources:
Abstract