The recurrence rates of Hepatocellular carcinoma (HCC) are high, necessitating novel and effective adjuvant therapies. Therefore, we conducted a phase II study of glypican-3 (GPC3) peptide vaccine as an adjuvant therapy for HCC patients. Forty-one patients with initial HCC who had undergone surgery or radiofrequency ablation (RFA) were analyzed in this phase II, open-label, single-arm trial. Ten vaccinations were performed for 1 y after curative treatment. We also investigated case-control subjects, where selected patients treated surgically during the same period were analyzed. The expression of GPC3 in the available primary tumors was determined by immunohistochemical analysis. Six patients received RFA therapy while 35 received surgery. The recurrence rate tended to be lower in the 35 patients treated with surgery plus vaccination compared to 33 patients who underwent surgery alone (28.6% vs. 54.3% and 39.4% vs. 54.5% at 1 and 2 y, respectively; p = 0.346, 0.983). Twenty-five patients treated with surgery and vaccination had GPC3-positive tumors; the recurrence rate in this group was significantly lower compared to that in 21 GPC3-positive patients who received surgery only (24% vs. 48% and 52.4% vs. 61.9% at 1 and 2 y, respectively; p = 0.047, 0.387). The GPC3 peptide vaccine improved the 1-y recurrence rate in patients with GPC3-positive tumors. This study demonstrated that GPC3 expression by the primary tumor may be used as a biomarker in a putative larger randomized clinical trial to determine the efficacy of the GPC3-derived peptide vaccine.

Lung cancer is the leading cause of cancer-related deaths worldwide. Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, have demonstrated marked clinical activity against non-small cell lung cancer (NSCLC) harboring activating epidermal growth factor receptor (EGFR) mutations. However, in most cases, patients develop acquired resistance to EGFR-TKI therapy. The threonine to methionine change at codon 790 of EGFR (EGFR T790M) mutation is the most common acquired resistance mutation, and is present in ~50% cases of TKI resistance. New treatment strategies for NSCLC patients harboring the EGFR T790M mutation are required. We evaluated the immunogenicity of an antigen derived from EGFR with the T790M mutation. Using BIMAS we selected several EGFR T790M-derived peptides bound to human leukocyte antigen (HLA)-A*02:01. T790M-A peptide (789–797) (IMQLMPFGC)-specific cytotoxic T lymphocytes (CTLs) were induced from peripheral blood mononuclear cells (PBMCs) of HLA-A2+ healthy donors. An established T790M-A-specific CTL line showed reactivity against the NCSLC cell line, H1975-A2 (HLA-A2+, T790M+), but not H1975 (HLA-A2−, T790M+), and the corresponding wild-type peptide (ITQLMPFGC)-pulsed T2 cells using an interferon-γ (IFN-γ) enzyme-linked immuno spot (ELISPOT) assay. This CTL line also demonstrated peptide-specific cytotoxicity against H1975-A2 cells. This finding suggests that the EGFR T790M mutation-derived antigen could be a new target for cancer immunotherapy.

Glypican-3 (GPC3) is a glycosylphosphatidylinositol-anchored cell surface protein overexpressed in hepatocellular carcinoma(HCC), and its overexpression is associated with poor prognosis. The diagnostic potential of GPC3 as a serum marker has been reported. In the present study, we evaluated the usefulness of plasma GPC3 as a predictor for recurrence after surgical resection in stage I HCC patients by newly developed an enzyme-linked immunosorbent assay (ELISA) system. Current study demonstrated that high levels of preoperative plasma GPC3 patients tended to experience postoperative recurrence. On the other hand, pre- and postoperative plasma GPC3 positivity of non-recurrence patients was very low. Moreover, even after surgery, approximately half of patients who experienced recurrence were positive for plasma GPC3. Postoperative plasma GPC3 positivity was significantly correlated with worse recurrence-free survival. Immuohistochemical analysis also showed positive rate of GPC3-expression in HCC was higher in recurrence patients than in non-recurrence patients. These results suggested that both pre- and postoperative plasma GPC3 levels may be accurate predictors for recurrence after curative resection of early-stage HCC. It should be noted that the current study only examined a small number of cases; thus, a larger sample size is necessary to validate GPC3 as a predictor for HCC recurrence.

The results of a Phase I clinical trial in which a glypican-3 (GPC3)-derived peptide was tested in advanced hepatocellular carcinoma patients point to a strong correlation between immunological and clinical responses. This commentary reviews our fundamental studies and clinical trials on the GPC3-derived peptide vaccine.

A woman in her 30s visited our hospital with stool abnormality. Esophagogastroduodenoscopy revealed a depressed lesion on the greater curvature of the gastric antrum. The tumor was diagnosed as a well-differentiated tubular adenocarcinoma based on the analysis of the biopsy specimen. The rapid urease test, histological examination, and serum anti-Helicobacter pylori antibody indicated that the patient was Helicobacter pylori negative. Gastric mucosal atrophy was not evident on esophagogastroduodenoscopy. Complete cure en bloc resection was successfully performed. The tumor was confined to the mucosa (pT1a-M). Immunohistochemistry showed positive CD10, MUC2, and CDX2 expression and negative MUC5AC and MUC6 expression. Thus, the phenotype was diagnosed as the intestinal phenotype. Helicobacter pylori-negative, well-differentiated early gastric cancer with intestinal phenotype has not been previously reported. Here, we report a rare and valuable case of Helicobacter pylori-negative early gastric cancer with intestinal phenotype treated by endoscopic submucosal dissection.