Cancer Research and Treatment

Original Articles

Microbial Dynamics Across Molecular Subtypes and Prognostic Significance of Lactobacillus in Gastric Cancer: Soo Kyung Nam, Juhyeong Park, Sujin Oh, Yoonjin Kwak, Cheol Min Shin, Kyoung Un Park, Nak-Jung Kwon, Seong-Ho Kong, Do Joong Park, Hyuk-Joon Lee, Han-Kwang Yang, Hye Seung Lee; Received April 25, 2025 Accepted July 16, 2025 Published online July 17, 2025; DOI: https://doi.org/10.4143/crt.2025.449 [Accepted]

Abstract PDF: Purpose
Recent studies have revealed a diverse gastric microbiota beyond Helicobacter pylori, suggesting a role in gastric cancer (GC). We aimed to investigate the composition and characteristics of the microbiota in GC and non-cancerous gastric mucosa (NC), with a particular focus on their relationship to molecular subtypes.
Materials and Methods
We conducted 16S rRNA sequencing and whole transcriptomic analysis on fresh-frozen GC and NC tissue samples from 192 GC patients, as well as saliva samples from 12 GC patients and 18 healthy individuals. Microsatellite instability (MSI), Epstein-Barr virus (EBV) in situ hybridization, and immunohistochemistry for p53 and E-cadherin were used to define molecular subtypes.
Results
GC tissues exhibited significantly higher diversity compared to matched NC tissues, with microbial profiles marked by decreased Helicobacter and increased Streptococcus, Prevotella, and Lactobacillus. Saliva samples predominantly contained oral bacteria and exhibited distinct microbial profiles from gastric tissues. In GC tissue, Helicobacter abundance was negatively correlated with key immune checkpoint genes (CTLA-4, PDCD1, CD274, and LAG3), whereas Prevotella, Streptococcus, and Fusobacterium were positively correlated. MSI-high and EBV-positive subtypes showed lower levels of Helicobacter but higher levels of Lactobacillus, Prevotella, and Streptococcus compared to the epithelial-mesenchymal transition (EMT)-like subtype. Notably, within MSI-H GC, a subgroup characterized by Lactobacillus-enriched and otherwise microbiota-depleted profiles was significantly associated with poorer overall and disease-free survival.
Conclusion
These findings underscore distinct microbial patterns across GC molecular subtypes, suggesting potential biomarkers for GC diagnosis and treatment.

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Gastrointestinal cancer

Longitudinal Comparative Analysis of Circulating Tumor DNA and Matched Tumor Tissue DNA in Patients with Metastatic Colorectal Cancer Receiving Palliative First-Line Systemic Anti-Cancer Therapy: Seung-been Lee, Ji-Won Kim, Hong-Geun Kim, Sung-Hyun Hwang, Kui-Jin Kim, Ju Hyun Lee, Jeongmin Seo, Minsu Kang, Eun Hee Jung, Koung Jin Suh, Se Hyun Kim, Jin Won Kim, Yu Jung Kim, Jee Hyun Kim, Nak-Jung Kwon, Keun-Wook Lee; Cancer Res Treat. 2024;56(4):1171-1182. Published online April 29, 2024; DOI: https://doi.org/10.4143/crt.2024.016

Abstract PDF Supplementary Material PubReader ePub

Purpose
This study aimed to compare tumor tissue DNA (ttDNA) and circulating tumor DNA (ctDNA) to explore the clinical applicability of ctDNA and to better understand clonal evolution in patients with metastatic colorectal cancer undergoing palliative first-line systemic therapy.
Materials and Methods
We performed targeted sequencing analysis of 88 cancer-associated genes using germline DNA, ctDNA at baseline (baseline-ctDNA), and ctDNA at progressive disease (PD-ctDNA). The results were compared with ttDNA data.
Results
Among 208 consecutively enrolled patients, we selected 84 (41 males; median age, 59 years; range, 35 to 90 years) with all four sample types available. A total of 202 driver mutations were found in 34 genes. ttDNA exhibited the highest mutation frequency (n=232), followed by baseline-ctDNA (n=155) and PD-ctDNA (n=117). Sequencing ctDNA alongside ttDNA revealed additional mutations in 40 patients (47.6%). PD-ctDNA detected 13 novel mutations in 10 patients (11.9%) compared to ttDNA and baseline-ctDNA. Notably, seven mutations in five patients (6.0%) were missense or nonsense mutations in APC, TP53, SMAD4, and CDH1 genes. In baseline-ctDNA, higher maximal variant allele frequency (VAF) values (p=0.010) and higher VAF values of APC (p=0.012), TP53 (p=0.012), and KRAS (p=0.005) mutations were significantly associated with worse overall survival.
Conclusion
While ttDNA remains more sensitive than ctDNA, our ctDNA platform demonstrated validity and potential value when ttDNA was unavailable. Post-treatment analysis of PD-ctDNA unveiled new pathogenic mutations, signifying cancer’s clonal evolution. Additionally, baseline-ctDNA’s VAF values were prognostic after treatment.

Citations

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Precision-Guided Durable Response From Venetoclax With Decitabine in a Patient With a Metastatic Refractory IDH2 -Mutant Cholangiocarcinoma
Eylül Özgü, Ünal Metin Tokat, Ashkan Adibi, Şevval Nur Bilgiç, Esranur Aydın, Onur Tutar, Mutlu Demiray
JCO Precision Oncology.2025;[Epub] CrossRef
Evolution of Neo-RAS-WT in Circulating Tumor DNA from First-Line to Subsequent Therapies in Metastatic Colorectal Cancer
Marco Siringo, Michela De Meo, Irene Bottillo, Paola Grammatico, Enrico Cortesi, Chiara Nicolazzo, Paola Gazzaniga
Cancers.2025; 17(7): 1070. CrossRef
Liquid biopsy in gastrointestinal oncology: clinical applications and translational integration of ctDNA, CTCs, and sEVs
Rita Palieri, Maria De Luca, Francesco Balestra, Giorgia Panzetta, Claudio Lotesoriere, Federica Rizzi, Angela Dalia Ricci, Rita Mastrogiacomo, Maria Lucia Curri, Luigi Andrea Laghi, Gianluigi Giannelli, Nicoletta Depalo, Maria Principia Scavo
Oncology Reviews.2025;[Epub] CrossRef
Circulating Tumor DNA as a Biomarker for Precision Medicine in Prostate Cancer: A Systematic Review
Nouhaila Chanhih, Abdelilah Laraqui, Salma Hassine, Ahmed Ameur, Larbi Hamedoun, Hicham El Annaz, Rachid Abi, Mohamed Rida Tagajdid, Idriss Lahlou Amine, Khalid Ennibi, Abdelaziz Benjouad, Lamiae Belayachi
International Journal of Molecular Sciences.2025; 26(22): 11049. CrossRef

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Effector Function Characteristics of Exhausted CD8+ T-Cell in Microsatellite Stable and Unstable Gastric Cancer: Dong-Seok Han, Yoonjin Kwak, Seungho Lee, Soo Kyung Nam, Seong-Ho Kong, Do Joong Park, Hyuk-Joon Lee, Nak-Jung Kwon, Hye Seung Lee, Han-Kwang Yang; Cancer Res Treat. 2024;56(4):1146-1163. Published online April 12, 2024; DOI: https://doi.org/10.4143/crt.2024.317

Abstract PDF PubReader ePub

Purpose
Gastric cancer exhibits molecular heterogeneity, with the microsatellite instability–high (MSI-H) subtype drawing attention for its distinct features. Despite a higher survival rate, MSI-H gastric cancer lack significant benefits from conventional chemotherapy. The immune checkpoint inhibitors, presents a potential avenue, but a deeper understanding of the tumor immune microenvironment of MSI-H gastric cancer is essential.
Materials and Methods
We explored the molecular characteristics of CD8+ T-cell subtypes in three MSI-H and three microsatellite stable (MSS) gastric cancer samples using single-cell RNA sequencing and spatial transcriptome analysis.
Results
In MSI-H gastric cancer, significantly higher proportions of effector memory T cell (Tem), exhausted T cell (Tex), proliferative exhausted T cell (pTex), and proliferative T cell were observed, while MSS gastric cancer exhibited significantly higher proportions of mucosal-associated invariant T cell and natural killer T cell. In MSI-H gastric cancer, Tex and pTex exhibited a significant upregulation of the exhaustion marker LAG3, as well as elevated expression of effector function markers such as IFNG, GZMB, GZMH, and GZMK, compared to those in MSS gastric cancer. The interferon γ (IFN-γ) signaling pathway of Tex and pTex was retained compared to those of MSS gastric cancer. The spatial transcriptome analysis demonstrates the IFN-γ signaling pathway between neighboring Tex and malignant cell, showcasing a significantly elevated interaction in MSI-H gastric cancer.
Conclusion
Our study reveals novel finding indicating that IFN-γ signaling pathway is retained in Tex and pTex of MSI-H gastric cancer, offering a comprehensive perspective for future investigations into immunotherapy for gastric cancer.

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Neurogranin facilitates maintaining the immunosuppressive state of hepatocellular carcinoma by promoting TGF-β1 secretion
Dongjie Ye, Zhu Zhang, Yuxin Yao, Banglun Pan, Hao Wu, Xinyu Zhang, Xiaoqian Wang, Nanhong Tang
International Journal of Biological Macromolecules.2025; 311: 143716. CrossRef
T-cell senescence: Unlocking the tumor immune “Dark Box” - A multidimensional analysis from mechanism to tumor immunotherapeutic intervention
Jia Cheng, Jian Zheng, Chen Ma, Yongzhang Li, Hua Hao
Seminars in Cancer Biology.2025; 113: 190. CrossRef
Hybrid model for predicting microsatellite instability in colorectal cancer using hematoxylin & eosin-stained images and clinical features
Hangping Wei, Xiaowei Zhang, Zhen Zhou, Jianbin Xie, Weidong Han, Xiaofang Dong
Frontiers in Oncology.2025;[Epub] CrossRef
Gallic acid potentiates the tumour-killing function of CD8+ T cells in gastric cancer
Si Chen, HaiBin Wang, Meixu Lei, Yumin Li, Qi Wang, Hengxin Wang, Yifei Shen, Xuejie Su, Yali Zhou
Journal of Pharmacy and Pharmacology.2025;[Epub] CrossRef
Simvastatin induces ferroptosis and activates anti-tumor immunity to sensitize anti-PD-1 immunotherapy in microsatellite stable gastric cancer
Yumei Ning, Shilin Fang, Runan Zhang, Jun Fang, Kun Lin, Yang Ding, Haihang Nie, Jingkai Zhou, Qiu Zhao, Hengning Ke, Haizhou Wang, Fan Wang
International Immunopharmacology.2024; 142: 113244. CrossRef

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