Novel Biomarkers for Prediction of Response to Preoperative Systemic Therapies in Gastric Cancer

Neoadjuvant PD-1 blockade plus chemotherapy versus chemotherapy alone in locally advanced stage II-III gastric cancer: A single-centre retrospective study

BACKGROUND

PD-1 blockade has been shown to have promising efficacy and acceptable safety profiles in advanced and metastatic gastric cancer; however, the efficacy and safety of neoadjuvant PD-1 blockade-based immunotherapy plus chemotherapy in locally advanced gastric cancer (LAGC) remain uncertain.

METHODS

We performed a retrospective review of patients with LAGC who received neoadjuvant treatment followed by D2 radical resection at the Affiliated Hospital of Qingdao University from 2019 to 2021. The primary aim was to investigate the difference in pathological response rates between neoadjuvant PD-1 immunotherapy plus chemotherapy and neoadjuvant chemotherapy alone. Multivariable models for pathological complete response (pCR) were constructed to investigate the factors that facilitate pCR.

TRIAL REGISTRATION

QYFYWZLL27406.

RESULTS

A total of 77 patients were included in the analysis, among whom 34 (44.2%) received neoadjuvant PD-1 blockade immunotherapy plus chemotherapy. A higher pCR rate was observed in the neoadjuvant PD-1 blockade immunotherapy plus chemotherapy group (8 of 34, 23.5% vs. 2 of 43, 4.7%, P=0.019). Multivariate logistic regression analysis of pCR revealed neoadjuvant PD-1 blockade plus chemotherapy regimen promoted pCR (OR 12.95, P=0.016). Regarding safety, 76.5% (26 of 34) of patients in the PD-1 blockade plus chemotherapy group and 76.7% (33 of 43) of patients in the chemotherapy group experienced treatment-related adverse events (TRAEs), and grade 3 or worse adverse events were 29.4% (10 of 34) and 34.9% (15 of 43), respectively.

CONCLUSION

Neoadjuvant PD-1 blockade plus chemotherapy induced a higher pCR rate than neoadjuvant chemotherapy, and the combined therapy was tolerable in LAGC patients.

Molecular markers as predictors of response to perioperative chemotherapy in locally advanced gastric cancer

Introduction. Perioperative FLOT chemotherapy has improved prognosis in patients with locally advanced resectable gastric cancer (GC). However, in 80 % of cases, the tumor is resistant to the therapy, resulting in unnecessary toxicity and delayed surgical treatment.

Aim. Evaluation of clinico-morphological patterns of microsatellite instability, HER2 gene amplification, changes in gene copy number and their relationship with the response to perioperative FLOT chemotherapy in patients with locally advanced resectable GC.

Materials and methods. The retrospective study included 185 patients. All tumor samples were assessed for HER2 and microsatellite instability status. Among all cases there were 45 patients with locally advanced T2–4N1–2 M0 GC, who underwent a total or subtotal gastrectomy with D2 lymphadenectomy and perioperative chemotherapy with FLOT. Microsatellite instability detection was performed using fragment analysis, HER2 gene amplification testing – fluorescent in situ hybridization. Also 19 patients were tested for copy number changes of the FGFR1, FGFR2, KRAS, MET, EGFR, CCND1, MYC genes using Multiplex ligation-dependent probe amplification. The endpoints were progression-free survival and objective response rate.

Results. Microsatellite instability was detected in 4.8 % (9/185) of GC cases. Microsatellite instability was associated with advanced age (p = 0.005), low grade of differentiation (p = 0.011), presence of tumor-infiltrating lymphocytes (p = 0.0004), and high preoperative CA 72–4 levels (p = 0.025). Prevalence of HER2 amplification was 7.5 % (14/185). It was associated with low grade of differentiation (p = 0.048) and metastasis in regional lymph nodes (p = 0.037). PFS in patients with HER2-positive (HER2 – human epidermal growth factor receptor 2) GC treated with perioperative FLOT chemotherapy (4/45) was significantly lower than in patients with HER2-negative GC: the median was 156 and 317 days, respectively (hazard ratio 0.49; 95 % confidence interval 0.16–1.47; p = 0.0006). There was no correlation between the presence of the alteration and ORR (p = 1.0). Progression-free survival in GC patients with KRAS amplification (3/19) was significantly lower comparing with patients without it: the median was 98 and 327 days, respectively (hazard ratio 0.29; 95 % confidence interval 0.07–1.19; p <0.0001). There was no association between an increase in KRAS copy number and objective response rate (p = 1.0). For microsatellite instability and other studied markers no statistically significant correlation with progression-free survival and objective response rate was found (p >0.05).

Conclusion. The presence of HER2 and KRAS amplification have been shown as promising predictive markers of the treatment failure in patients treated with perioperative FLOT chemotherapy for locally advanced resectable GC.

Genetic and immune microenvironment characterization of HER2-positive gastric cancer: Their association with response to trastuzumab-based treatment

BACKGROUND

We aimed to determine the molecular and immune microenvironment characteristics of HER2-positive gastric cancer (GC) related to the patient's response to first-line trastuzumab-based treatment.

METHODS

Eighty-three cases of HER2-positive advanced gastric adenocarcinoma patients treated with trastuzumab were enrolled. Targeted deep sequencing and transcriptome analysis were performed on selected 21 cases (exploration cohort) along with two post-treatment samples. The results were compared between patients progressed before 6 months (Group 2) and others (Group 1), and were validated by FISH and immunohistochemistry in total cohort. Tumor-infiltrating immune cells were evaluated using RNA sequencing data and multiplex immunohistochemistry. Progression-free survival (PFS) analysis was performed.

RESULTS

Group 1 showed frequent amplification of G1/S cell cycle checkpoint-related genes and upregulated KEGG pathways related to cell proliferation. In contrast, Group 2 had more frequent EGFR, HER3, and MET amplification and higher RNA expression in immune-related KEGG pathways than Group 1. In total cohort, significant predictors of better PFS were cell cycle-related including CCNE1 amplification, Cyclin A and PLK1 overexpression, and decreased Cyclin D3 and HER3 expression (p < 0.05), or immune-related including high density of CD3^- CD57⁺ NK cells and PD-L1 combined positive score ≥5 (p < 0.05). The best prognostic predictors were a combination of Cyclin A, Cyclin E, p21, and HER3 (p < 0.001).

CONCLUSION

HER2-positive GC with favorable response to trastuzumab were characterized by cell cycle-related gene alterations and increased CD3^- CD57⁺ NK cell infiltration. These findings would be helpful to the fine modulation of therapeutic strategies for patients with HER2-positive GC.

Tumor vessel normalization and immunotherapy in gastric cancer

Gastric cancer (GC) is a common malignant tumor, and patients with GC have a low survival rate due to limited effective treatment methods. Angiogenesis and immune evasion are two key processes in GC progression, and they act synergistically to promote tumor progression. Tumor vascular normalization has been shown to improve the efficacy of cancer immunotherapy, which in turn may be improved through enhanced immune stimulation. Therefore, it may be interesting to identify synergies between immunomodulatory agents and anti-angiogenic therapies in GC. This strategy aims to normalize the tumor microenvironment through the action of the anti-vascular endothelial growth factor while stimulating the immune response through immunotherapy and prolonging the survival of GC patients.

CD44v6 High Membranous Expression Is a Predictive Marker of Therapy Response in Gastric Cancer Patients

In gastric cancer (GC), biomarkers that define prognosis and predict treatment response remain scarce. We hypothesized that the extent of CD44v6 membranous tumor expression could predict prognosis and therapy response in GC patients. Two GC surgical cohorts, from Portugal and South Korea (n = 964), were characterized for the extension of CD44v6 membranous immuno-expression, clinicopathological features, patient survival, and therapy response. The value of CD44v6 expression in predicting response to treatment and its impact on prognosis was determined. High CD44v6 expression was associated with invasive features (perineural invasion and depth of invasion) in both cohorts and with worse survival in the Portuguese GC cohort (HR 1.461; 95% confidence interval 1.002–2.131). Patients with high CD44v6 tumor expression benefited from conventional chemotherapy in addition to surgery (p < 0.05), particularly those with heterogeneous CD44v6-positive and -negative populations (CD44v6_3+) (p < 0.007 and p < 0.009). Our study is the first to identify CD44v6 high membranous expression as a potential predictive marker of response to conventional treatment, but it does not clarify CD44v6 prognostic value in GC. Importantly, our data support selection of GC patients with high CD44v6-expressing tumors for conventional chemotherapy in addition to surgery. These findings will allow better stratification of GC patients for treatment, potentially improving their overall survival.

Phenotypic Plasticity Conferred by the Metastatic Microenvironment of the Brain Strengthens the Intracranial Tumorigenicity of Lung Tumor Cells

Lung cancer is the leading cause of cancer-related deaths and is the primary source of brain metastases. Despite great advances in the study of the genetics and etiology of lung cancer in previous decades, the identification of the factors and mechanisms underlying the brain metastasis of lung tumors is still an open question. In this study, the results of bioinformatic conjoint analysis revealed that the metastatic microenvironment in the brain conferred lung tumor cell phenotypic plasticity, characterized by neural cell-like and embryonic–stem cell-like features. Meanwhile, the metabolic phenotype of the educated tumor cells underwent transition characterized by oxygen-related metabolism. The results of the experiments demonstrated that the downregulation of HOXB9 weakened the tumorigenicity of lung tumor cells. Bioinformatic prediction analysis also determined that many cell cycle-associated factors were potentially transcribed by HOXB9. Collectively, the results of this study suggested that under the influence of the metastatic environment of the brain, lung tumor cells seemed to acquire phenotypic plasticity characterized by neural cell-like features, and this transition may be associated with the aberrant upregulation of HOXB9.

Mechanisms of Pharmaceutical Therapy and Drug Resistance in Esophageal Cancer

Pharmaceutical therapies are essential for esophageal cancer (EC). For the advanced EC, the neoadjuvant therapy regimen, including chemotherapy plus radiotherapy and/or immunotherapy, is effective to achieve clinical benefit, even pathological complete response. For the unresectable, recurrent, and metastatic EC, the pharmaceutical therapy is the limited effective regimen to alleviate the disease and prolong the progression-free survival and overall survival. In this review, we focus on the pharmaceutical applications in EC treatment including cytotoxic agents, molecular targeted antibodies, and immune checkpoint inhibitors (ICIs). The chemotherapy regimen is based on cytotoxic agents such as platinum-based complexes, fluorinated pyrimidines and taxenes. Although the cytotoxic agents have been developed in past decades, the standard chemotherapy regimen is still the cisplatin and 5-FU or paclitaxel because the derived drugs have no significant advantages of overcoming the shortcomings of side effects and drug resistance. The targeted molecular therapy is an essential supplement for chemotherapy; however, there are only a few targeted therapies available in clinical practice. Trastuzumab and ramucirumab are the only two molecular therapy drugs which are approved by the US Food and Drug Administration to treat advanced and/or metastatic EC. Although the targeted therapy usually achieves effective benefits in the early stage therapy of EC, the patients will always develop drug resistance during treatment. ICIs have had a significant impact on routine clinical practice in cancer treatment. The anti-programmed cell death-1 monoclonal antibodies pembrolizumab and nivolumab, as the ICIs, are recommended for advanced EC by several clinical trials. However, the significant issues of pharmaceutical treatment are still the dose-limiting side effects and primary or secondary drug resistance. These defects of pharmaceutical therapy restrain the clinical application and diminish the effectiveness of treatment.

Relationship between the Expression of the Thymidylate Synthase and the Prognosis of Gastric Cancer Patients Treated with Combinational Chemotherapy Regimen Including Fluorouracil, Docetaxel and Cisplatin

Background: Thymidylate synthase is one of the target enzymes of 5-fluorouracil. However, the clinical and prognostic significance of TS expression in gastric cancer has remained controversial. In this study, the expression of thymidylate synthase was evaluated in gastric cancer patients treated with combinational chemotherapy; moreover, the association between TS expression and clinicopathologic characteristics and overall survival of the patients were also assessed.

Materials and Methods: In this descriptive study, 89 pathological samples were gathered from patients at Kermanshah hospitals during 2008-2017. The survival status of patients was recorded and their overall survival was evaluated individually.

Results: The average survival period for low and high thymidylate synthase groups was 54 and 50 months, respectively, meaning higher survival time in the lower thymidylate group. But this difference was not statistically significant (log Rank=0.88). In addition, sex, stage, recurrence, and survival had no significant difference between the low and high expression of thymidylate synthase groups (p=0.89).

Conclusion: The results clearly indicated that the level of thymidylate synthase is not a significant modulator of 5- fluorouracil in gastric cancer patients. Nevertheless, evaluation of the level of the enzymes and markers as well as their effects are highly recommended for accurate selection of chemotherapeutical strategies.

A phase II trial of the FGFR inhibitor pemigatinib in patients with metastatic esophageal-gastric junction/gastric cancer trastuzumab resistant: the FiGhTeR trial

Background:

Prognosis of patients affected by metastatic esophageal–gastric junction (EGJ) or gastric cancer (GC) remains dismal. Trastuzumab, an anti-HER2 monoclonal antibody, is the only targeted agent approved for the first-line treatment of patients with HER2-overexpressing advanced EGJ or GC in combination with chemotherapy. However, patients invariably become resistant during this treatment. We recently identified the overexpression of fibroblast growth factor (FGF) receptor 3 (FGFR3) as a molecular mechanism responsible for trastuzumab resistance in GC models, providing the rationale for the inhibition of this receptor as a potential second-line strategy in this disease. Pemigatinib is a selective, potent, oral inhibitor of FGFR1, 2, and 3.

Methods:

The FiGhTeR trial is a phase II, single-arm, open-label study to assess safety and activity of the FGFR inhibitor pemigatinib as second-line treatment strategy in metastatic EGJ/GC patients progressing under trastuzumab-containing therapies. The primary endpoint is the 12-week progression-free survival rate. Plasma and tumor tissue samples will be collected for translational research analyses at baseline, during treatment, and at progression on pemigatinib.

Discussion:

Co-alterations in genes coding for different tyrosine-kinase receptors are emerging as relevant mechanisms of acquired resistance to anti-HER2 therapeutic strategies in GC. In particular, our group has recently identified that in GC models the overexpression of FGFR3 sustains the acquired resistance to trastuzumab. This trial aims to assess the safety, tolerability and activity of the FGFR inhibitor pemigatinib as a second-line treatment in metastatic EGJ/GC patients refractory to first-line trastuzumab-containing therapies. Furthermore, this study offers the opportunity to prospectively study mechanisms and pathways involved in trastuzumab resistance.

Protocol number:

CRC2017_02

EudraCT Number:

2017-004522-14