A Review of Emerging Biomarkers for Immune Checkpoint Inhibitors in Tumors of the Gastrointestinal Tract

Identification and validation of a PD-L1-related signature from mass spectrometry in gastric cancer

BACKGROUND

According to the guidelines, PD-L1 expression is a critical indicator for guiding immunotherapy application. According to certain studies, regardless of PD-L1 expression, immunotherapy could be advantageous for individuals with gastric cancer. Therefore, new scoring systems or biomarkers are required to enhance treatment strategies.

METHODS

Mass spectrometry and machine learning were used to search for strongly related PD-L1 genes, and the NMF approach was then used to separate gastric cancer patients into two categories. Differentially expressed genes (DEGs) between the two subtypes identified in this investigation were utilized to develop the UBscore predictive model, which was verified by the Gene Expression Omnibus (GEO) database. Coimmunoprecipitation, protein expression, and natural killing (NK) cell coculture experiments were conducted to validate the findings.

RESULTS

A total of 123 proteins were identified as PD-L1 interactors that are substantially enriched in the proteasome complex at the mRNA level. Using random forest, 30 UPS genes were discovered in the GSE66229 cohort, and ANAPC7 was experimentally verified as one of 123 PD-L1 interactors. Depending on the expression of PD-L1 and ANAPC7, patients were separated into two subgroups with vastly distinct immune infiltration. Low UBscore was related to increased tumor mutation burden (TMB) and microsatellite instability-high (MSI-H). In addition, chemotherapy medications were more effective in individuals with a low UBscore. Finally, we discovered that ANAPC7 might lead to the incidence of immunological escape when cocultured with NK-92 cells.

CONCLUSION

According to our analysis of the PD-L1-related signature in GC, the UBscore played a crucial role in prognosis and had a strong relationship with TMB, MSI, and chemotherapeutic drug sensitivity. This research lays the groundwork for improving GC patient prognosis and treatment response.

Association of Tumor-Infiltrating Lymphocytes With Survival in Stages II and III Colorectal Cancer

The tumor microenvironment is crucial in tumourigenesis, response to therapy, and elimination of tumor cells. Tumor-infiltrating lymphocytes (TILs) promote the host immune response and are associated with a better prognosis in colorectal cancer (CRC). This multicentric retrospective study evaluated the relationship between the presence and intensity of TILs and survival outcomes. A total of 651 patients from four Portuguese oncological centers who underwent surgical resection for stages II or III colorectal adenocarcinoma between 2016 and 2019 were included in this study. The mean age of the study population was 70 years; 58.2% were males. The median overall survival was 58.03 ± 1.29 months (95% confidence interval (CI) 55.50 - 60.56), and the median disease-free survival (DFS) was 53.02 ± 1.39 months (95% CI 50.29 - 55.74). Patients with high infiltrate (including those with moderate, abundant, or Crohn-like infiltrate) had significantly longer DFS i.e., 58.48 ± 1.84 months (95% CI 54.87 - 62.09 months) vs 49.22 ± 1.75 months (95% CI 45.79 - 52.64 months) in the group with absent or minimal infiltrate; p = 0.003. Assessing the side of the tumor, high infiltrate was associated with higher DFS (59.86 ± 2.36 months (95% CI 55.23 - 64.50 months) vs 49.60 ± 2.40 months (95% CI 44.90 - 54.29 months), p = 0.011). This work reinforces the importance of research into possible prognostic and predictive factors in patients with CRC.