Shinobu Tomochika

Cetuximab strongly enhances immune cell infiltration into liver metastatic sites in colorectal cancer

Cetuximab has activity against colorectal cancers. Recent studies demonstrated that cetuximab induces antibody‐dependent cell‐mediated cytotoxicity via immune cells, and a new immune‐related mechanism of inducing immunogenic cell death. This study aimed to evaluate the immune responses induced by cetuximab in tumor microenvironments at liver metastasis sites of metastatic colorectal cancer patients. We assessed immune cell infiltration in the liver metastatic sites of 53 colorectal cancer patients. These patients were divided into three groups according to the treatment before operation: chemotherapy with cetuximab, chemotherapy without cetuximab, and no chemotherapy. The inflammatory cells in the liver metastatic sites were assessed by hematoxylin–eosin staining, focusing on the invasive margin. The overall inflammatory reaction and number of lymphoid cells were assessed with a four‐point scoring system. We then assessed immune cell infiltration (CD3, CD8 and CD56) in 15 liver metastatic sites. Hematoxylin–eosin staining demonstrated more inflammatory cells in the chemotherapy with cetuximab group than in the other groups (P < 0.001). Of note, inflammatory cells were found in intratumoral areas, and the destruction of cancer cell foci was observed in the chemotherapy with cetuximab group. Moreover, a higher infiltration of CD3+ (P = 0.003), CD8+ (P = 0.003) and CD56+ (P = 0.001) cells was observed in the chemotherapy with cetuximab group than in the other groups. These results suggest that cetuximab might have an immune‐enhancing effect. As such, the immune‐related mechanism of action of cetuximab may enhance the efficacy of combination therapy, such as chemotherapy and immunotherapy using therapeutic peptides.

Prediction of the efficacy of immunotherapy by measuring the integrity of cell‐free DNA in plasma in colorectal cancer

We previously reported a phase II study of a cancer vaccine using five novel peptides recognized by HLA‐A*2402‐restricted CTL in combination with oxaliplatin‐containing chemotherapy (FXV study) as first‐line therapy for patients with metastatic colorectal cancer and demonstrated the safety and promising potential of our five‐peptide cocktail. The objective of this analysis was to identify predictive biomarkers for identifying patients who are likely to receive a clinical benefit from immunochemotherapy. Circulating cell‐free DNA (cfDNA) in plasma has been reported to be a candidate molecular biomarker for the efficacy of anticancer therapy. Unlike uniformly truncated small‐sized DNA released from apoptotic normal cells, DNA released from necrotic cancer cells varies in size. The integrity of plasma cfDNA (i.e. the ratio of longer fragments [400 bp] to shorter fragments [100 bp] of cfDNA), may be clinically useful for detecting colorectal cancer progression. We assessed plasma samples collected from 93 patients prior to receiving immunochemotherapy. The cfDNA levels and integrity were analyzed by semi‐quantitative real‐time PCR. Progression‐free survival was significantly better in patients with a low plasma cfDNA integrity value than in those with a high value (P = 0.0027). Surprisingly, in the HLA‐A*2402‐matched group, patients with a low plasma cfDNA integrity value had significantly better progression‐free survival than those with a high value (P = 0.0015). This difference was not observed in the HLA‐A*2402‐unmatched group. In conclusion, the integrity of plasma cfDNA may provide important clinical information and may be a useful predictive biomarker of the outcome of immunotherapy in metastatic colorectal cancer.

Low invasiveness of thoracoscopic esophagectomy in the prone position for esophageal cancer: a propensity score-matched comparison of operative approaches between thoracoscopic and open esophagectomy

BackgroundIn this study, cytokine levels, outcome, and survival rates after esophagectomy for esophageal cancer were retrospectively investigated in a propensity score-matched comparison of operative approaches between the thoracoscopic esophagectomy (TE) in the prone position and open esophagectomy (OE).Patients and MethodsBetween 2005 and 2014, TE was performed on a group of 85 patients, which was compared with a group of 104 OE cases. Eventually, 65 paired cases were matched using propensity score matching.ResultsAlthough the TE group underwent a significantly longer operation time than the OE group (P < 0.001), the TE group exhibited less blood loss (P < 0.001) and had a shorter postoperative hospital stay (P = 0.038) than the OE group. The serum interleukin-6 levels on ICU admission (P < 0.001) and on POD 1 (P < 0.001) were significantly lower in the TE group. The interleukin-10 levels on ICU admission (P < 0.001), POD 1 (P = 0.016), and POD 3 (P < 0.001) were also significantly lower in the TE group. Pulmonary complication was significantly lower in the TE group (P = 0.043). The 5-year PFS rates in the TE and OE groups were 70.6 and 58.7% (P = 0.328), respectively, and OS rates were 64.9 and 50.2% (P = 0.101), respectively.ConclusionTE compared to OE is a less invasive procedure with lower surgical stress and less pulmonary complication for the treatment of esophageal squamous cell carcinoma.

miR-125b-1 and miR-378a are Predictive Biomarkers for the Efficacy of Vaccine Treatment against Colorectal Cancer

Many clinical trials of peptide vaccines have been conducted. However, these vaccines have provided clinical benefits in only a small fraction of patients. The purpose of the present study was to explore microRNAs (miRNAs) as novel predictive biomarkers for the efficacy of vaccine treatment against colorectal cancer. First, we carried out microarray analysis of pretreatment cancer tissues in a phase I study, in which peptide vaccines alone were given. Candidate miRNAs were selected by comparison of the better prognosis group with the poorer prognosis group. Next, we conducted microarray analysis of cancer tissues in a phase II study, in which peptide vaccines combined with chemotherapy were given. Candidate miRNAs were further selected by a similar comparison of prognosis. Subsequently, we carried out reverse‐transcription PCR analysis of phase II cases, separating cancer tissues into cancer cells and stromal tissue using laser capture microdissection. Treatment effect in relation to overall survival (OS) and miRNA expression was analyzed. Three miRNA predictors were negatively associated with OS: miR‐125b‐1 in cancer cells (P = 0.040), and miR‐378a in both cancer cells (P = 0.009) and stromal cells (P < 0.001). Multivariate analysis showed that expression of miR‐378a in stromal cells was the best among the three predictors (HR, 2.730; 95% CI, 1.027–7.585; P = 0.044). In conclusion, miR‐125b‐1 and miR‐378a expression might be considered as novel biomarkers to predict the efficacy of vaccine treatment against colorectal cancer.

Outcomes following liver resection for multinodular Barcelona Clinic Liver Cancer‑B hepatocellular carcinoma

Management of multinodular hepatocellular carcinoma (HCC) in the intermediate Barcelona Clinic Liver Cancer (BCLC)-B stage is controversial. The aim of the present study as to identify the subgroup of patients with BCLC-B HCC who could benefit from liver resection. The present study retrospectively analyzed the outcomes of 65 patients (training cohort) who underwent liver resection for multinodular BCLC-B HCC. Coxs regression analysis was conducted to identify the independent prognostic factors for overall survival and to develop the prognostic score. As some authors have reported that maximum tumor size (cm) plus tumor number (N+S) is a prognostic factor in patients with BCLC-B HCC who undergo chemoembolization, the usefulness of this factor in patients who underwent liver resection was also evaluated. Subsequently, the validity of the prognostic score was assessed in an independent validation cohort (n=132). Multivariate analysis revealed that positivity for hepatitis C virus antibody (HCV-ab), platelet count ≤1010/l, N+S >8, and des-γ-carboxy prothrombin (DCP) >400 mAU/ml were independent prognostic factors for overall survival. The prognostic score differentiated two groups (≤2, ≥3) with distinct outcomes (median survival time 68.3 months vs. 29.1 months; P<0.0001). This result was confirmed in an external validation cohort. Therefore, surgery can promote long-term survival in patients with multinodular HCC although the indications for surgery are limited. HCV-Ab status, preoperative platelet count, DCP level and N+S may be useful for patient selection.

Efficacy of Perioperative Immunonutrition in Esophageal Cancer Patients Undergoing Esophagectomy

OBJECTIVE Malnutrition is common in patients with esophageal cancer, resulting in increased postoperative complications and mortality. Although preoperative immunonutrition can significantly reduce the incidence of postoperative infectious complications, its effect in patietns with esophageal cancer undergoing esophagectomy remains unclear. The aim of this study was to investigate the effects of perioperative immunonutritional support on the postoperative course and long-term survival of this group of patients. METHODS This prospective, randomized study enrolled 40 patients with thoracic esophageal carcinoma undergoing esophagectomy. The patients were divided into two groups and received either immunomodulating enteral nutrition (IMPACT group; IG) or standard enteral nutrition (Ensure group; EG) continuously for 7 d before and 7 d after surgery. Nutritional status, such as rapid turnover protein, postoperative intensive care unit (ICU) length of stay (LOS), postoperative hospital LOS, morbidity, and mortality were investigated prospectively. RESULTS There were no significant differences in patient demographic characteristics between the two groups. Levels of retinol-binding protein, as a rapid-turnover protein, were significantly higher on postoperative day (POD) -1, 7, and 14 in the IG compared with the EG group (P = 0.009, P = 0.004, and P = 0.024, respectively). The incidence of postoperative infectious complications and changes to therapeutic antibiotics were significantly lower in the IG group than in the EG group (P = 0.048 and P = 0.012, respectively). There was no significant difference in postoperative ICU or postoperative hospital LOS between the two groups. The 5-y progression-free survival rates in the IG and EG groups were 75% and 64%, respectively (P = 0.188), and the overall survival rates were 68% and 55%, respectively (P = 0.187). CONCLUSIONS Perioperative immunonutrition may improve early postoperative nutritional status and reduce postoperative infectious complications in patients with esophageal cancer undergoing esophagectomy.

Abstract 1927: The significance of calreticulin in pancreatic cancer: a molecule highly expressed in pancreatic cancer stem-like cells

Cancer stem-like cells (CSLCs) in solid tumors are thought to be resistant to conventional chemotherapy or molecular targeting therapy and to contribute to cancer recurrence and metastasis. In this study, we aimed to identify a biomarker of pancreatic CSLCs (P-CSLCs). P-CSLC-enriched population was generated from pancreatic cancer cell lines using our previously reported method and its protein expression profile was compared with that of parental cells by two-dimensional electrophoresis and tandem mass spectrometry. The results indicated that a chaperone protein calreticulin (CRT) was significantly upregulated in P-CSLCs compared to parental cells. Flow cytometry analysis demonstrated that CRT was mostly localized to the surface of P-CSLCs and did not correlate with the levels of CD44v9, another P-CSLC biomarker. Furthermore, the side population in CRThigh/CD44v9low population is much higher than that in CRTlow/CD44v9high population. CRT expression was also assessed by immunohistochemistry in pancreatic cancer tissues (n = 80) obtained after radical resection and was found to be associated with patients’ clinicopathological features and disease outcomes in the Cox’s proportional hazard regression model. Multivariate analysis identified CRT as an independent prognostic factor for pancreatic cancer patients, along with age and post-operative therapy. Our results suggest that CRT can serve as a biomarker of P-CSLCs and a prognostic factor associated with poorer survival of pancreatic cancer patients. This novel biomarker can be useful for detecting P-CSLCs independently, which had been detectable by multiple surface markers like CD24, CD44 and ESA. We will present CSLCs properties of CRThigh population in P-CSLCs. Citation Format: Satoshi Matsukuma, Kiyoshi Yoshimura, Atsunori Oga, Moeko Inoue, Takuya Fujimtoto, Atsuo Kuramasu, Masanori Fuse, Ryouichi Tsunedomi, Hidetoshi Eguchi, Hiroto Matsui, Shinsuke Kanekiyo, Yukio Tokumitsu, Shinobu Tomochika, Michihisa Iida, Yoshihiro Tokuhisa, Kazuhiko Sakamoto, Nobuaki Suzuki, Tomoko Furuya-Kondo, Hiroshi Itoh, Shigeru Takeda, Shigeru Yamamoto, Shigefumi Yoshino, Shoichi Hazama, Tomio Ueno, Hiroaki Nagano. The significance of calreticulin in pancreatic cancer: a molecule highly expressed in pancreatic cancer stem-like cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1927. doi:10.1158/1538-7445.AM2017-1927