Abstract 1994P
Background
Tumour immune microenvironment (TIME) assessment is thought to be effective tool for evaluation of tumour-host interplay and prognostication of different cancers development, including gastric carcinoma (GC). As inflammatory signaling is closely related with DNA-repair pathways, there could be the link between GC immune contexture and DNA-repair enzymes expression defining response to different therapies. This study aimed to assess the relations between TIME and theranostic markers expression in GC of different histological types.
Methods
In this retrospective study we assessed 50 cases (29 males and 21 females; 52.5±2.18 years old) of the locally advanced or metastatic GC naïve to preoperative chemotherapy and radiotherapy. Among enrolled cases there were 15 diffuse GC and 35 intestinal-type GC according to Lauren’s classification. The number of CD8+, CD68+ and CD163+ cells as well as expression of ERCC1, TOPO2A and PD-L1 were assessed immunohistochemically.
Results
Intestinal-type GCs were associated with enhanced infiltration by CD8+ cells (P=0.002), high rate of PD-L1 expression (P=0.03) and CD163+ cells number. In contrast, diffuse GCs demonstrated mostly immune desert phenotype and CD68+ macrophages were the most prevalent within tumour nests and stroma (P<0.001). The lowest rate of ERCC1 expression was found in GC with high CD8+ infiltration (P =0.047) regardless histological type. Whereas high TOPO2A expression was mostly related with highly CD8-infiltrated GCs of intestinal type (P=0.018). Notably, PD-L1 expression was more often in intestinal type GCs rich in CD163+ macrophages (P=0.03).
Conclusions
Various histological types of GC demonstrated distinct immunogenisity and were related with different expression of theranostic biomarkers that could affect both immune escape mechanisms and resistance to therapies.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Laboratory of Pathology \"CSD Health Care\".
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.