Protein phosphatase 6 promotes stemness of colorectal cancer cells.

Colorectal cancer (CRC) remains a significant global health concern, demanding a more profound comprehension of its molecular foundations for the development of improved therapeutic strategies. This study aimed to elucidate the role of protein phosphatase 6 (PP6), a member of the type 2A protein phosphatase family, in CRC. Protein phosphatase 6 functions as a heterotrimer with a catalytic subunit (PP6c), regulatory subunits (PP6Rs; PP6R1, PP6R2, and PP6R3), and scaffold subunits (ANKRD28, ANKRD44, and ANKRD52). Elevated PP6c expression has been identified in CRC tissues compared to normal mucosa, aligning with its potential involvement in CRC pathogenesis. PP6c knockdown resulted in decreased colony-forming ability and in vivo proliferation of various CRC cell lines. Transcriptome analysis revealed that PP6c knockdown resulted in altered expression of genes associated with cancer stemness. Notably, the PP6c-PP6R3 complex is a key player in regulating cancer stem cell (CSC) markers. Additionally, increased PP6c expression was observed in CSC-like cells induced by sphere formation, implicating the role of PP6c in CSC maintenance. This study highlights the role of PP6c in CRC and suggests that it is a potential therapeutic target disrupting a pathway critical for CRC progression and stem cell maintenance.

A novel index combining fecal immunochemical test, DNA test, and age improves detection of advanced colorectal adenoma.

Although the fecal immunochemical test for hemoglobin (FIT) is a widely used screening test for colorectal cancer, it is not sensitive enough to detect advanced colorectal adenoma. To address this issue, we performed this study to investigate whether combining the FIT and fecal DNA testing of methylated somatostatin (SST) could improve diagnostic performance for advanced colorectal adenoma. We collected feces from 79 healthy subjects with negative results on colonoscopy, 43 patients with non-advanced colorectal adenoma, 117 patients with advanced colorectal adenoma, and 126 patients with colorectal cancer. After fecal DNA was incubated with methylation-sensitive restriction enzymes, SST methylation levels were measured by droplet digital PCR. Using logistic multivariate analysis, we established a prediction formula for detecting colorectal neoplasia and named it the FAMS (FIT, age, methylated SST) index. The diagnostic performance of a single use of FIT for advanced colorectal adenoma showed a sensitivity of 29.1% (34/117) and specificity of 89.3% (109/122). In contrast, the FAMS index showed a sensitivity of 56.4% (66/117) at a similar specificity point of 91.0% (111/122). Furthermore, even at the higher specificity point of 94.3% (115/122), the sensitivity was still higher than that of FIT, reaching 42.7% (50/117). As the FAMS index showed better diagnostic performance for advanced colorectal adenoma than a single use of FIT, the FAMS index could be a promising tool for detecting advanced colorectal adenoma.

High serum proteinase-3 levels predict poor progression-free survival and lower efficacy of bevacizumab in metastatic colorectal cancer.

BACKGROUND: To improve the prognosis of patients with metastatic colorectal cancer (mCRC), investigating predictive biomarkers of their prognosis and chemotherapeutic responsiveness is necessary. This study aimed to analyze the clinical significance of serum proteinase-3 (PRTN3) as a predictor for prognosis and chemosensitivity, especially to bevacizumab therapy, in mCRC. METHODS: This single-center retrospective observational study enrolled 79 patients with mCRC in our hospital and 353 patients with colorectal cancer in the TCGA database. Preoperative serum PRTN3 levels were measured using an enzyme-linked immunosorbent assay. The clinicopathological characteristics and prognosis according to serum PRTN3 levels were then evaluated. PRTN3 expression in tumor and stromal cells was evaluated immunohistochemically. The impact of PRTN3 levels on angiogenesis and bevacizumab sensitivity was evaluated using the tube formation assay. RESULTS: Serum PRTN3 levels were an independent poor prognostic factor for progression-free survival (PFS) (hazard ratio, 2.082; 95% confidence interval, 1.118-3.647; P=0.010) in patients with mCRC. Similarly, prognostic analysis with TCGA data sets showed poorer overall survival in patients with PRTN3 expression than that in patients without PRTN3 expression, especially in patients with stage IV. Immunohistochemical analysis of resected specimens revealed that stromal neutrophils expressed PRTN3, and their expression level was significantly correlated with serum PRTN3 levels. Interestingly, the effectiveness of first-line chemotherapy was significantly poorer in the high serum PRTN3 level group. High serum PRTN3 was significantly associated with poor PFS (hazard ratio, 3.027; 95% confidence interval, 1.175-7.793; P=0.0161) in patients treated with bevacizumab, an anti-angiogenic inhibitor. The tube formation assay revealed that PRTN3 administration notably augmented angiogenesis while simultaneously attenuating the anti-angiogenic influence exerted by bevacizumab therapy. CONCLUSIONS: Serum PRTN3 levels could be a novel predictive biomarker of PFS of first-line chemotherapy, especially for bevacizumab therapy, in patients with mCRC.

IL-6 Levels Correlate with Prognosis and Immunosuppressive Stromal Cells in Patients with Colorectal Cancer.

BACKGROUND: The prognosis for patients with colorectal cancer (CRC) is determined by tumor characteristics as well as the host immune response. This study investigated the relationship between an immunosuppressive state and patient prognosis by evaluating the systemic and tumor microenvironment (TME) interleukin (IL)-6 levels. METHODS: Preoperative serum IL-6 levels were measured using an electrochemiluminescence assay. Expression of IL-6 in tumor and stromal cells was evaluated immunohistochemically in 209 patients with resected CRC. Single-cell analysis of tumor-infiltrating immune cells was performed using mass cytometry in 10 additional cases. RESULTS: Elevated serum IL-6 levels were associated with elevated stromal IL-6 levels and a poor prognosis for patients with CRC. High IL-6 expression in stromal cells was associated with low-density subsets of CD3+ and CD4+ T cells as well as FOXP3+ cells. Mass cytometry analysis showed that IL-6+ cells among tumor-infiltrating immune cells were composed primarily of myeloid cells and rarely of lymphoid cells. In the high-IL-6-expression group, the percentages of myeloid-derived suppressor cells (MDSCs) and CD4+FOXP3highCD45RA- effector regulatory T cells (eTreg) were significantly higher than in the low-IL-6-expression group. Furthermore, the proportion of IL-10+ cells in MDSCs and that of IL-10+ or CTLA-4+ cells in eTregs correlated with IL-6 levels. CONCLUSION: Elevated serum IL-6 levels were associated with stromal IL-6 levels in CRC. High IL-6 expression in tumor-infiltrating immune cells also was associated with accumulation of immunosuppressive cells in the TME.

[A Severe Case of Bleeding from Duodenal Invasion Due to Co-Morbid IPMC with Arcuate Ligament Syndrome and IPDA Aneurysm].

An 81-year-old man with a history of left hemiplegia due to a cerebral hemorrhage was admitted to a clinic because of tarry stools. Endoscopic findings revealed an ulcerative lesion with hemorrhage in the descending duodenum. The patient was transferred to our hospital for treatment. Because endoscopic hemostasis was impossible, interventional radiology(IVR) hemostasis was performed using coil embolization for the feeding artery. Simultaneously, angiography showed stenosis of the root of the celiac axis due to arch ligament syndrome and an aneurysm of the inferior pancreaticoduodenal artery (IPDA). Due to the risk of rebleeding, subtotal stomach-preserving pancreatoduodenectomy was performed after the patient's overall condition had stabilized. Despite dissecting the arcuate ligament, the hepatic artery flow did not improve. Hence, a direct arterial anastomosis between the middle colic artery and the gastroduodenal artery was performed. Furthermore, due to the proximity of the IPDA aneurysm to the superior mesenteric artery, IVR embolization for the IPDA aneurysm was performed on postoperative day 8, and he was transferred to a rehabilitation hospital on postoperative day 57. The pathological result was invasive intraductal papillary mucinous carcinoma(IPMC). The patient has been an outpatient with no recurrence 12 months postoperatively.

CD4 and FOXP3 as predictive markers for the recurrence of T3/T4a stage II colorectal cancer: applying a novel discrete Bayes decision rule.

BACKGROUND: We recently reported the relapse-free survival (RFS) significance of the combination of CD4+ and forkhead box P3+ (FOXP3) T-cell densities identified by immunohistochemistry in patients with stage I, II, and III colorectal cancer (CRC) who underwent curative resections. This study was designed to determine the optimal combination of markers that predict recurrence in patients with T factors of T3/T4a stage II CRC by applying a novel Bayes decision rule. METHODS: Using 137 cancer tissue specimens from T3/T4a stage II patients, 12 clinicopathologic and immune factors were analysed as predictive candidates for recurrence. RESULTS: Our study showed that the combination of low CD4+ and low FOXP3+ T-cell densities resulted in extremely poor RFS. CONCLUSIONS: Adjuvant chemotherapy may be considered for patients with a combination of low CD4+ and low FOXP3+ T-cell densities. The discovery of this new prognostic indicator is important for the appropriate management of patients undergoing curative resection for T3/T4a stage II CRC.

[Tumor Immunogenicity and Immune Checkpoint Inhibitors].

Cancer immunotherapy including immune checkpoint inhibitors(ICIs)have established itself as the fourth cancer therapy. However, the response rate of ICIs is still only about 20%, and tumors resistant to ICIs are often so-called"cold-tumor"with low tumor immunogenicity. Therefore, research and development is being conducted worldwide on how to convert cold- tumors into hot-tumors with high immunogenicity. In this paper, we review the relationship between tumor immunogenicity and ICI, as well as therapeutic methods to enhance tumor immunogenicity, and introduce our research about novel cancer peptide vaccination therapy.

[Surgical Resection of Gastric GIST Liver Metastasis with Giant Cystic Mass-A Case Report].

The patient is a woman in her 80s who underwent a partial gastrectomy for a gastric GIST 14 years ago. This time, she presented our department with upper abdominal distention and computed tomography revealed an 18 cm-sized cystic lesion in the left lobe of the liver. Since a nodule enhancement was observed in the cyst, malignant disease such as hepatic cystadenocarcinoma could not be ruled out and surgical resection was performed. Pathological examination revealed liver metastasis of gastric GIST. In Japan, only 14 cases have been reported showing such late recurrence with liver metastasis more than 10 years after resection of a primary tumor, including our case. In addition, the cystic finding in this case made preoperative diagnosis difficult because a needle biopsy could not be performed to obtain a pathological diagnosis.

[A Case in Which FOLFOXIRI Was Useful as Preoperative Chemotherapy for Locally Advanced Rectal Cancer with Difficulty in Securing CRM].

The patient is a 65-year-old woman. Colonoscopy performed for close examination of constipation and lower abdominal pain revealed a circumferential type 3 lesion in the rectum Ra. A CT scan showed invasion of the primary lesion into the extramural and sacral front and multiple metastases in the mesorectal lymph nodes but no distant metastasis. Staging laparoscopy was performed. As the mesorectum around the primary lesion was tightly adherent, it was difficult to R0 resection; hence, only construction of colostomy was performed. We have introduced chemotherapy(FOLFOXIRI plus bevacizumab therapy), and 4 courses were administered. Post-treatment CT scan showed that the peri-invasiveness of the primary tumor had disappeared and the enlarged lymph nodes had shrunk. Furthermore, SUVmax of PET-CT for main lesion was decreased, dramatically. On day 109 after the initial surgery, laparoscopic low anterior resection was performed. Although the left hypogastric nerve was resected, other areas could be dissected and R0 resection could be performed. FOLFOXIRI therapy has shown good early-tumor shrinkage and depth of response and may be useful for patients with locally advanced rectal cancer who have difficulty securing circumferential resection margin(CRM).

Novel adjuvant dendritic cell therapy with transfection of heat-shock protein 70 messenger RNA for patients with hepatocellular carcinoma: a phase I/II prospective randomized controlled clinical trial.

INTRODUCTION: A proteomic analysis of hepatocellular carcinoma (HCC) has revealed that Heat Shock Protein 70 (HSP70) is among the cancer antigen proteins of HCC. Moreover, we confirmed that HSP70 was highly expressed in HCC by immunohistochemical staining. Based on these results, we developed an HSP70 mRNA-transfected dendritic cell (DC) therapy for treating unresectable or recurrent HCC, and the phase I trial was completed successfully. Thus, we aimed to investigate the safety and efficacy of this therapy as a postoperative adjuvant treatment after curative resection for HCC to prevent recurrence by conducting a phase I/II randomized controlled clinical trial. METHODS: Patients (n = 45) with resectable HCC of stages II-IVa were registered and randomly assigned into two groups (DC group: 31 patients, control group: 14 patients) before surgery. The primary endpoint was disease-free survival (DFS), and the secondary endpoints were safety and overall survival. The DC therapy was initially administered at approximately 1 week after surgery, and twice every 3-4 weeks thereafter. RESULTS: No adverse events specific to the immunotherapy were observed in the DC group. There was no difference in DFS between the DC and control groups (p = 0.666). However, in the subgroup with HSP70-expressing HCC, DFS of the DC group tended to be better (p = 0.090) and OS of the DC group was significantly longer (p = 0.003) than those of the control group. CONCLUSION: The HSP70 mRNA-transfected DC therapy was performed safely as an adjuvant therapy. The prognosis of HSP70-expressing HCC cases could be expected to improve with this therapy.

Determining the protective characteristics and risk factors for the development of anastomotic leakage after low anterior resection for rectal cancer.

PURPOSE: Anastomotic leakage is one of the most serious postoperative complications associated with surgery for rectal cancer. The present study aimed to identify the protective characteristics and risk factors associated with anastomotic leakage after low anterior resection for rectal cancer. METHODS: This was a retrospective, single-center study conducted between January 2009 and December 2017 at our institution. In total, 136 rectal cancer patients who underwent low anterior resection were included in the study. We analyzed preoperative and intraoperative factors. In addition, the pelvic dimensions were measured using computed tomography in all cases. RESULTS: Among the 136 patients, anastomotic leakage occurred in 21 (15.4%), including 18 males and 3 females. The median body mass index was 21.1 kg/m2. The construction of a covering stoma was found to be a protective factor. In addition, the operation time (≥ 373 min), intraoperative blood loss (≥ 105 ml), and size of the pelvic inlet (≥ 113 mm) were identified as risk factors for anastomotic leakage. CONCLUSION: The construction of a covering stoma was a possible protective factor. However, a longer operation time, higher intraoperative blood loss, and larger pelvic inlet dimensions were possible risk factors for developing anastomotic leakage after low anterior resection in patients with rectal cancer.

[Immune-Related Factors as Prognostic Markers for Resectable Colorectal Cancer].

BACKGROUND: Tumor infiltration of CD3 and CD8-positive T cells has been reported as a good prognostic marker for patients with colorectal cancer(CRC). To clarify the significance of CD4 and FOXP3-positive T cells in CRC for prognosis of intratumoral infiltration. METHODS: CD3, CD8, CD4 and FOXP3-positive T cells were immunostained(IHC)from tissue specimens of 342 CRC patients who underwent curative resection to quantify the number of infiltrating cells in the tumor. Microsatellite instability(MSI)was also evaluated in 322 samples and the clinicopathological factors and survival were analyzed. RESULTS: Highly infiltrated groups of CD3, CD4 and FOXP3-positive T cells were associated with improved relapse-free survival(RFS). Highly infiltrated groups of CD8, CD4 and FOXP3-positive T cells were associated with improved disease- specific survival(DSS). Invasion depth, vascular infiltration, and CD4-positive T cell density were independent prognostic factors for DSS. CD4 and FOXP3-positive T cell infiltration was not associated with the high-frequency microsatellite instability group, in contrast to CD3 and CD8-positive T cell infiltration. CONCLUSIONS: Intratumoral CD4-positive T cell density and FOXP3-positive T cell densities were stronger prognostic indicators than other clinicopathological features. These results may facilitate the establishment of novel prognostic factors and therapeutic strategies for CRC.

[Postoperative Management of Refractory Pleural Effusion in a Patient with Esophageal Cancer Accompanied by Cirrhosis].

This study reports a case of a 61-year-old man with a chief complaint of anemia. The patient was diagnosed with esophageal cancer(Stage Ⅰ). Preoperative examination revealed alcoholic liver cirrhosis(Child-Pugh A, liver damage B). After a period of abstinence to improve liver function, minimally invasive esophagectomy, retrosternal reconstruction with a gastric tube, and two-field lymph node dissection were performed. The thoracic duct was preserved during the operation. Post- surgery, the bill pleural effusion was increased. Drainage was initiated using thoracentesis with frosemide, spironolactone, and tolvaptan. On post-operating day(POD)35, the patient was discharged; however, right pleural effusion continued to increase. Therefore, cell-free and concentrated reinfusion therapy for right pleural effusion was performed on POD 56. After the treatment, the pleural effusion was well-controlled with 20 mg of frosemide. This case suggested that cell-free and concentrated pleural effusion reinfusion therapy contributed to the management of refractory pleural effusion in patients with esophageal cancer accompanied by cirrhosis.

[A Resected Case of Advanced Lower Rectal Cancer with Neoadjuvant Chemotherapy by FOLFOXIRI plus Cetuximab].

Although the current standard of care for patients with lower rectal cancer in Japan includes total mesorectal resection with lateral lymph node dissection, postoperative local and distant recurrence rates are high. Multidisciplinary treatment is important to improve the prognosis. A man in his 30s was diagnosed with lower rectal cancer due to bloody stool and referred to our department. He was diagnosed as cT3N3M0, cStage Ⅲc with right obturator lymph node metastasis. Four courses of neoadjuvant chemotherapy(NAC)with FOLFOXIRI plus cetuximab were performed. Because Grade 3 neutropenia was observed in the first cycle(CTCAE v5.0), pegfilgrastim was administered in the second and subsequent cycles, and NAC was completed without dose reduction. The patient underwent laparoscopy-assisted intersphincteric rectal resection and D3+rtLD2 dissection. Histopathological resection margins were negative, and the resection was R0. Lymph node metastasis was found only in No. 263d-rt, and the pathological diagnosis was ypT3N3M0, pStage Ⅲc. Histological evaluation of response to treatment was Grade 2. The postoperative course was good and the patient was discharged on postoperative day 15. The patient received 8 courses of adjuvant chemotherapy with mFOLFOX6 from the 7th postoperative week and is alive and recurrence-free 6 months after surgery.

[A Case of Intrahepatic Cholangiocarcinoma in the Elderly Patient with Curative Resection after Neoadjuvant Chemotherapy].

An 80 year-old woman with anorexia and jaundice was diagnosed with mass-forming intrahepatic cholangiocarcinoma, lymph node metastasis, common hepatic duct strictures, and obstructive jaundice. PET-CT showed FDG accumulation in the primary lesion(SUVmax 19.0)and swollen lymph nodes. Her ADL and major organ functions were judged to be sufficient for treatment. After treatment for jaundice, she received a total of 6 courses of gemcitabine, cisplatin plus S-1(GCS)therapy as neoadjuvant chemotherapy(NAC). Her first treatment was an 80% dose of GCS, but she was subsequently diagnosed with Grade 4 thrombocytopenia(CTCAE v5.0). The dose of gemcitabine was further reduced, and no adverse events of Grade 3 or higher were observed thereafter. After NAC, PET-CT showed decreased FDG accumulation in the primary lesion(SUVmax 3.3)and normalization of FDG accumulation in the lymph nodes. Extended right hepatectomy and biliary reconstruction were performed as radical resection(R0). The final diagnosis was pT2, N0, M0, Stage Ⅱ. After hepatectomy, her anorexia and poor ADL persisted. She was discharged to her home 151 days after her surgery.

[A Case of Pseudo-Meigs' Syndrome Caused by Ovarian Metastasis from Colon Cancer].

This case pertains to a female patient in her 60s who was diagnosed with carcinoma in the cecum with lung, ovarian, and peritoneal metastases. She complained of abdominal distension and poor feeding because her ascites and ovarian metastasis worsened 18 months after chemotherapy initiation. Repeated cytologic examination of the ascitic fluid revealed no malignant cells. Therefore, Pseudo-Meigs' syndrome was suspected. Bilateral salpingo-oophorectomy was performed as palliative surgery because of the patient's reduced capacity to perform activities of daily living(ADL)due to ascites. After palliative surgery, her ascites disappeared, and she was able to better perform ADL. Further, chemotherapy was resumed. The patient remains well 10 months after surgery. This case highlights the importance of considering Pseudo-Meigs' syndrome in patients with massive ascites and ovarian metastasis, because surgical resection can improve their quality of life.

[A Case of Combined Hepatocellular Carcinoma and Cholangiocarcinoma with Multidisciplinary Treatment Including Lenvatinib].

A 49-year-old man came to our department for the purpose of scrutinizing liver tumor. CA19-9 and CA125 increased, and AFP and PIVKA-Ⅱ were within the normal range. CT showed a large number of early ring enhanced tumor, and a tumor thrombus in the left branch of the portal vein. Tumor biopsy revealed adenocarcinoma. Chemotherapy(gemcitabine, cisplatin plus S-1: GCS)was performed for intrahepatic cholangiocarcinoma(r/o combined hepatocellular carcinoma and cholangiocarcinoma). Lenvatinib was administered because portal vein tumor thrombus and PIVKA-Ⅱ increased after GCS therapy. Two months later, CA19-9 and PIVKA-Ⅱ were decreased and portal vein tumor thrombus was shrunk. Extended left hepatectomy was performed for the purpose of disease control. Histopathological examination revealed some hepatocellular carcinoma components in intrahepatic cholangiocarcinoma. Tumor thrombus was vitrified and necrotic. After hepatectomy, administration of lenvatinib was continued for the residual lesion, and no significant tumor growth was observed.

[A Case of Anastomotic Recurrence of Rectal Cancer Treated by Laparoscopic Total Pelvic Exenteration after Neoadjuvant Chemoradiation].

Patient is 69-year-old man, who underwent a high anterior resection with laparoscopic support for rectal cancer. The patient was diagnosed with anastomotic recurrent rectal cancer after 14 months after surgery. The pelvic MRI scan showed invasion of the prostate and seminal vesicles, so NACRT was performed. Tumors were found to have decreased in size, although there was still some residual invasion of the prostate and seminal vesicle. Laparoscopic total pelvic exenteration (Lap-TPE), and combined excision of the anal elevator muscle and bladder were performed. Preoperative diagnosis was ycT4b, N0, M0, ycStage Ⅱ, and pathological diagnosis was pT4b (prostate and seminal vesicles), INF b, Ly2, v2, Pn1b, pPM0, pDM0, pRM0, and pN0. Laparoscopic surgery allowed to operate safely, with minimal blood loss and a good field of vision. After postoperative adjuvant chemotherapy, lung and liver metastasis appeared after 6 months after surgery, but there was no local recurrence. The patient is treated with chemotherapy, and the metastases are under control. The patient is survive 17 months after Lap-TPE.

[A Case of Gastrointestinal Stromal Tumor of the Lower Rectum That Enabled Minimally Invasive Surgery with Imatinib Mesylate as Neoadjuvant Chemotherapy].

A 67-year-old woman was admitted with melena. A colonoscopy detected a 50 mm submucosal tumor close to the dentate line. We diagnosed the rectal gastrointestinal stromal tumor by EUS-FNA. With the expectation of tumor shrinkage and strong hope of the patient, we started imatinib mesylate as neoadjuvant chemotherapy. A CT scan after 3 months after administration of imatinib mesylate showed the reduction of the size to 35 mm. We operated transanal endoscopic surgery considering the localization of the tumor. From histopathological findings, the tumor was low risk in the modified-Fletcher classification, and low risk in the Miettinen classification. Eight months after the operation, no recurrence was observed without further adjuvant chemotherapy. In this case, we were able to resect the tumor without injuring the film of tumor by operating transanal endoscopic surgery, because of tumor shrinkage with imatinib mesylate as neoadjuvant chemotherapy. I considered that using imatinib mesylate preoperatively was contributed to minimally invasive surgery.

A phase I study of multi-HLA-binding peptides derived from heat shock protein 70/glypican-3 and a novel combination adjuvant of hLAG-3Ig and Poly-ICLC for patients with metastatic gastrointestinal cancers: YNP01 trial.

BACKGROUND: This phase I study aimed to evaluate the safety, peptide-specific immune responses, and anti-tumor effects of a novel vaccination therapy comprising multi-HLA-binding heat shock protein (HSP) 70/glypican-3 (GPC3) peptides and a novel adjuvant combination of hLAG-3Ig and Poly-ICLC against metastatic gastrointestinal cancers. METHODS: HSP70/GPC3 peptides with high binding affinities for three HLA types (A*24:02, A*02:01, and A*02:06) were identified with our peptide prediction system. The peptides were intradermally administered with combined adjuvants on a weekly basis. This study was a phase I dose escalation clinical trial, which was carried out in a three patients' cohort; in total, 11 patients were enrolled for the recommended dose. RESULTS: Seventeen patients received this vaccination therapy without dose-limiting toxicity. All treatment-related adverse events were of grades 1 to 2. Peptide-specific CTL induction by HSP70 and GPC3 proteins was observed in 11 (64.7%) and 13 (76.5%) cases, respectively, regardless of the HLA type. Serum tumor marker levels were decreased in 10 cases (58.8%). Immunological analysis using PBMCs indicated that patients receiving dose level 3 presented with significantly reduced T cell immunoglobulin and mucin-domain containing-3 (TIM3)-expressing CD4 + T cells after one course of treatment. PD-1 or TIM3-expressing CD4 + T cells and T cell immunoreceptor with immunoglobulin and ITIM domains (TIGIT)-expressing CD8 + T cells in PBMCs before vaccination were negative predictive factors for survival. CONCLUSIONS: This novel peptide vaccination therapy was safe for patients with metastatic gastrointestinal cancers.