Abstract 3982
Background
A special role in the tumour progression is played by heterogeneous components of the microenvironment of tumours, premetastatic tumour niches, influencing which seems likely to change the disease course. Our purpose was to analyze some characteristics of the local cellular immunity in metastatic GC.
Methods
33 GC patients aged 30-80 years were divided into 2 groups: group 1 – M0, non-metastatic GC, n = 17, mean age 61.7±8.9 years (G2 – 11, G3 – 6 patients); group 2 – M1, GC with peritoneal and omentum metastases, n = 16, mean age 58.7±11.5 years (G2 – 7, G3 – 5, G4 - 3 patients). Tumours (T), peritumoral tissues (PT), omentum (O) and peritoneum (P) tissues were studied. Lymphocytes were determined by flow cytometry using FACSCantoII (BD) and T-, B-, NK antibody panels; quantitative content of DN (CD3+CD4-CD8-), DP (CD3+CD4+CD8+) T lymphocytes and regulatory (T-regs) T cells (CD4+CD25+CD127dim) was studied.
Results
Patients with M1 GC demonstrated increased CD3+ lymphocytic infiltration of T, PT, O and P tissues. IRI in M1 O was significantly higher than in M0 (1.95±0.3 vs 0.7±0.2), being similar in other tissues. Levels of DN lymphocytes were lower in O of M1, compared to M0 (7.7±2.5 vs 15.7±5.6, p ≤ 0.05). Contents of NK cells, NKT lymphocytes significantly decreased in O of M1 patients, compared to M0 (3.3≤1.1 vs 14.0≤2.3 and 1.7±0.5 vs 3.8±0.8, respectively). Higher levels of NKT lymphocytes were registered in M1 PT, compared to M0 (3.3±1.1 vs 1.3±0.4), as well as lower levels of NK cells in T (2.3±0.9 vs 5.33±0.2). Percentage of Treg lymphocytes in P and O were significantly lower in M1 than in M0 (respectively, 6.9±1.5 vs 12.6±4.9 and 5.9±1.3 vs 12.6±4.9). Higher amount of B lymphocytes was registered in all tissues of M1 patients, compared to M0, maximal in O (13.1±3.3 vs 3.4±1.5), T (23.5±5.1 vs 17.2±2.3) and P (8.2±3.4 vs 3.5±1.2), while in PT it was lower (15.7±4.2 vs 43.7±4.5).
Conclusions
GC metastasis to the omentum and peritoneum is characterized by a change in their immunological features – a decrease in the tissue level of NK and NKT lymphocytes, a loss in the prevalence of CD3+CD8+ due to an increase in the number of CD3+CD4+ cells, and an increase in the level of CD19 + (B2) lymphocytes. This probably contributes to the appearance of metastatic lesions in these organs in gastric cancer.
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.
Resources from the same session
5472 - Early response evaluation and CEA response in patients treated in a Danish randomized study comparing trifluridine/tipiracil (TAS-102) with or without bevazicumab in patients with chemorefractory metastatic colorectal cancer (mCRC)
Presenter: Camilla Qvortrup
Session: Poster Display session 2
Resources:
Abstract
2037 - Updated survival analysis of the randomized phase III trial comparing S-1 versus capecitabine in the first-line treatment of metastatic colorectal cancer (SALTO) by the Dutch Colorectal Cancer Group.
Presenter: Johannes Kwakman
Session: Poster Display session 2
Resources:
Abstract
3053 - JFMC51-1702-C7: Phase II study investigating efficacy and safety of trifluridine/tipiracil (FTD/TPI) plus bevacizumab (BEV) in patients (pts) with metastatic colorectal cancer (mCRC) refractory or intolerant to standard chemotherapies.
Presenter: Keisuke Kazama
Session: Poster Display session 2
Resources:
Abstract
3183 - Bevacizumab plus trifluridine/tipiracil in elderly patients with previously untreated metastatic colorectal cancer (KSCC 1602): A single-arm, Phase 2 study
Presenter: Akitaka Makiyama
Session: Poster Display session 2
Resources:
Abstract
3233 - Biweekly TAS-102 and Bevacizumab as a Third-Line Chemotherapy for metastatic colorectal cancer: A Phase II Multicenter Clinical Trial (TAS-CC4 study)
Presenter: Yoichiro Yoshida
Session: Poster Display session 2
Resources:
Abstract
5907 - Liquid biopsy concordance based on clonality and timing of testing in patients with metastatic colorectal cancer
Presenter: Pashtoon Kasi
Session: Poster Display session 2
Resources:
Abstract
1866 - Plasma clearance of RAS mutation under therapeutic pressure is a rare event in metastatic colorectal cancer
Presenter: Emilie Moati
Session: Poster Display session 2
Resources:
Abstract
2312 - High Circulating miR-1247 is a marker for poor prognosis in patients with metastatic colorectal cancer treated with chemotherapy and cetuximab
Presenter: Jakob Schou
Session: Poster Display session 2
Resources:
Abstract
5602 - Clinical relevance of circulating tumor (ct)DNA genotyping for first line cetuximab-based treatment monitoring in metastatic colorectal cancer (mCRC): a prospective multicentric study
Presenter: JOANA Vidal Barrull
Session: Poster Display session 2
Resources:
Abstract
3182 - Clonal hematopoiesis mutations in plasma cfDNA RAS/BRAF genotyping of metastatic colorectal cancer
Presenter: Beili Wang
Session: Poster Display session 2
Resources:
Abstract