Gastric cancer is a heterogeneous disease with diverse histological and genomic subtypes, making it difficult to demonstrate treatment efficacy in clinical trials. However, recent efforts have been made to identify molecular biomarkers with prognostic and predictive implications to better understand the broad heterogeneity of gastric cancer and develop effective targeted therapies for it. HER2 overexpression, HER2/neu amplification, MSI-H, and PD-L1+ are predictive biomarkers in gastric cancer, and a growing number of clinical trials based on novel biomarkers have demonstrated the efficacy of targeted therapies alone or in combination with conventional chemotherapy. Enrichment design clinical trials of targeted therapies against FGFR2b and claudin 18.2 have demonstrated efficacy in unresectable advanced gastric cancer. Nonetheless, it is essential to continuously validate promising molecular biomarkers and introduce them into clinical practice to optimize treatment selection and improve patient outcomes. In this review, we focused on established (PD-L1, HER2, MSI) and emerging biomarkers (FGFR2, CLDN18.2) in gastric cancer, their clinical significance, detection methods, limitations, and molecular agents that target these biomarkers.

This retrospective multicenter study analyzed 244 patients with unresectable hepatocellular carcinoma treated with lenvatinib (LEN) and atezolizumab + bevacizumab (Atezo + Bev) to examine the characteristics, treatment courses, and prognoses. The cases of patients who could achieve HCC downstaging from Barcelona Clinic Liver Cancer (BCLC) stage B or C to A or zero indicated the need for conversion therapy. The patients’ prognoses with and without conversion therapy were compared. Of the 244 patients, 12 (4.9%) underwent conversion therapy, six out of 131 (4.6%) were treated with LEN, and six out of 113 (5.3%) were treated with Atezo + Bev. Eleven patients (91.7%) with a modified albumin bilirubin (mALBI) grade 1 or 2a and BCLC-B stage showed significantly higher rates of transition during conversion therapy (p < 0.05). The patients undergoing conversion therapy had a significantly longer median overall survival rate than those receiving chemotherapy alone (1208 [1064–NA] vs. 569 [466–704] days, p < 0.01). A comparison of the patients who achieved a partial response with and without conversion was evaluated using propensity score matching to reduce the confounding factors, showing a significant survival benefit in the conversion group (1208 [1064–NA] vs. 665 days, p < 0.01). Among the patients with u-HCC who were treated with LEN and Atezo + Bev, those with mALBI 1 + 2a and BCLC-B were likely to achieve conversion therapy with downstaging.

Introduction: Lenvatinib (LEN) is a novel potent multi-tyrosine kinase inhibitor, approved as first-line treatment for unresectable hepatocellular carcinoma (HCC). Considering its high objective response rate, LEN therapy could be expected to achieve downstaging of tumors and lead to conversion therapy with hepatectomy or ablation. However, the feasibility of conversion therapy after LEN treatment in unresectable HCC remains largely unknown. Patient concerns: Here, we reported 3 cases of unresectable HCC: case 1, a 69-year-old man diagnosed with ruptured HCC; case 2, a 72-year-old woman with nonalcoholic steatohepatitis-based HCC; and case 3, a 73-year-old man with a history of alcoholic cirrhosis-based HCC. Diagnosis: In all cases, cirrhosis was classified as Child-Pugh 5 and modified albumin-bilirubin grade 1 or 2a. HCC was diagnosed as Barcelona Clinic Liver Cancer (BCLC) stage B. Interventions: In all cases, LEN was initiated after conventional-transcatheter arterial embolization enforcement, while maintaining liver function. Outcomes: In all cases, the main tumor size decreased after 6 months of LEN treatment and no satellite nodes were detected, indicating downstaging of HCC to BCLC stage A. Subsequently, conversion hepatectomy or ablation was performed. After successful conversion therapy, the general condition of the patients was good, without tumor recurrence during the observation period (median 10 months). Lessons: This study demonstrated that LEN enables downstaging of HCC and thus represents a bridge to successful surgery or ablation therapy. In particular, LEN treatment may facilitate the possibility for conversion therapy of initially unresectable HCC, while maintaining the hepatic functional reserve.

Gastric cancer (GC) is one of the most clinically challenging cancers worldwide. Over the past few years, new molecular-targeted agents and immunotherapy have markedly improved GC prognosis. Human epidermal growth factor receptor 2 (HER2) expression is a key biomarker in first-line chemotherapy for unresectable advanced GC. Further, the addition of trastuzumab to cytotoxic chemotherapy has extended the overall survival of patients with HER2-positive advanced GC. In HER2-negative GC, the combination of nivolumab, an immune checkpoint inhibitor, and a cytotoxic agent has been demonstrated to prolong the overall survival of GC patients. Ramucirumab and trifluridine/tipiracil, which are second- and third-line treatments for GC, and trastuzumab deruxtecan, an antibody–drug conjugate for HER2-positive GC, have been introduced in clinics. New promising molecular-targeted agents are also being developed, and combination therapy comprising immunotherapy and molecular-targeted agents is expected. As the number of available drugs increases, it is important to understand the target biomarkers and drug characteristics and select the optimal therapy for each patient. For resectable disease, differences in the extent of standard lymphadenectomy between Eastern and Western countries have led to different standard treatments: perioperative (neoadjuvant) and adjuvant therapy. This review aimed to summarize recent advances in chemotherapy for advanced GC.

The mechanism of resistance to sorafenib in hepatocellular carcinoma (HCC) remains unclear. We analyzed miRNA expression profiles in sorafenib-resistant HCC cell lines (PLC/PRF5-R1/R2) and parental cell lines (PLC/PRF5) to identify the miRNAs responsible for resistance. Drug sensitivity, migration/invasion capabilities, and epithelial-mesenchymal transition (EMT) properties were analyzed by biochemical methods. The clinical relevance of the target genes to survival in HCC patients were assessed using a public database. Four miRNAs were significantly upregulated in PLC/PRF5-R1/-R2 compared with PLC/PRF5. Among them, miR-125b-5p mimic-transfected PLC/PRF5 cells (PLC/PRF5-miR125b) and showed a significantly higher IC50 for sorafenib compared with controls, while the other miRNA mimics did not. PLC/PRF5-miR125b showed lower E-cadherin and higher Snail and vimentin expression—findings similar to those for PLC/PRF5-R2—which suggests the induction of EMT in those cells. PLC/PRF5-miR125b exhibited significantly higher migration and invasion capabilities and induced sorafenib resistance in an in vivo mouse model. Bioinformatic analysis revealed ataxin-1 as a target gene of miR-125b-5p. PLC/PRF5 cells transfected with ataxin-1 siRNA showed a significantly higher IC50, higher migration/invasion capability, higher cancer stem cell population, and an EMT phenotype. Median overall survival in the low-ataxin-1 patient group was significantly shorter than in the high-ataxin-1 group. In conclusion, miR-125b-5p suppressed ataxin-1 and consequently induced Snail-mediated EMT and stemness, leading to a poor prognosis in HCC patients.