Yoshitaka Honma

Circulating Exosomal microRNAs as Biomarkers of Colon Cancer

Purpose Exosomal microRNAs (miRNAs) have been attracting major interest as potential diagnostic biomarkers of cancer. The aim of this study was to characterize the miRNA profiles of serum exosomes and to identify those that are altered in colorectal cancer (CRC). To evaluate their use as diagnostic biomarkers, the relationship between specific exosomal miRNA levels and pathological changes of patients, including disease stage and tumor resection, was examined. Experimental Design Microarray analyses of miRNAs in exosome-enriched fractions of serum samples from 88 primary CRC patients and 11 healthy controls were performed. The expression levels of miRNAs in the culture medium of five colon cancer cell lines were also compared with those in the culture medium of a normal colon-derived cell line. The expression profiles of miRNAs that were differentially expressed between CRC and control sample sets were verified using 29 paired samples from post-tumor resection patients. The sensitivities of selected miRNAs as biomarkers of CRC were evaluated and compared with those of known tumor markers (CA19-9 and CEA) using a receiver operating characteristic analysis. The expression levels of selected miRNAs were also validated by quantitative real-time RT-PCR analyses of an independent set of 13 CRC patients. Results The serum exosomal levels of seven miRNAs (let-7a, miR-1229, miR-1246, miR-150, miR-21, miR-223, and miR-23a) were significantly higher in primary CRC patients, even those with early stage disease, than in healthy controls, and were significantly down-regulated after surgical resection of tumors. These miRNAs were also secreted at significantly higher levels by colon cancer cell lines than by a normal colon-derived cell line. The high sensitivities of the seven selected exosomal miRNAs were confirmed by a receiver operating characteristic analysis. Conclusion Exosomal miRNA signatures appear to mirror pathological changes of CRC patients and several miRNAs are promising biomarkers for non-invasive diagnosis of the disease.

Serum levels of hepatocyte growth factor and epiregulin are associated with the prognosis on anti-EGFR antibody treatment in KRAS wild-type metastatic colorectal cancer

Background:Ligands of transmembrane receptor tyrosine kinases have important roles in cell proliferation, survival, migration and differentiation in solid tumours. We conducted this study to evaluate the relationship between concentration of serum ligands and prognosis of patients with metastatic colorectal cancer (mCRC) treated with anti-epidermal growth factor receptor (EGFR) antibodies.Methods:Between August 2008 and August 2011, serum samples were obtained from KRAS wild-type patients who met the inclusion criteria and received an anti-EGFR antibody treatment. Serum concentration of ligands was measured by an enzyme-linked immunosorbent assay, and somatic mutations of KRAS, BRAF, PIK3CA and BRAF were analysed by direct sequencing.Results:A total of 103 patients were enrolled in the present study. At the pretreatment serum levels, patients with high levels of hepatocyte growth factor (HGF) had shorter progression-free survival (PFS) and overall survival (OS) compared with those with low levels of HGF (median PFS: 6.4 months vs 4.4 months; P<0.001, median OS: 15.3 months vs 8.0 months; P<0.001, respectively). Patients with high levels of epiregulin (EREG) also had shorter PFS and OS compared with those with low levels of EREG (median PFS: 6.6 months vs 4.9 months; P=0.016, median OS: 13.8 months vs 7.4 months; P=0.048, respectively). In addition, patients whose serum levels of ligands were elevated at progressive disease had shorter PFS and OS compared with other patients.Conclusions:Our study indicated that high levels of HGF and EREG were associated with resistance to treatment with anti-EGFR antibodies in KRAS wild-type patients with mCRC. Our findings will contribute to the newly combination therapy on the treatment of anti-EGFR antibodies.

Serum level of hepatocyte growth factor is a novel marker of predicting the outcome and resistance to the treatment with trastuzumab in HER2-positive patients with metastatic gastric cancer

HER2-overexpression in tumor tissue is observed in 6 to 23% of advanced gastric cancer (GC) cases, and trastuzumab is an active molecular drug for these patients. There are no data available on whether serum levels of ligands are associated with the response and resistance to trastuzumab in HER2-positive patients with metastatic GC. HER2 screening of 502 patients with advanced gastric cancer was performed in our institution. Among these patients, 84 patients (16.8%) were diagnosed as HER2-positive, and those who were treated with trastuzumab and met the inclusion criteria were enrolled in the present study. Serum levels of ligands that affect the HER2 signal pathway were measured by an enzyme-linked immunosorbent assay. Forty-six HER2-positive patients were enrolled in this study, and 26 patients (56.5%) achieved a partial response to treatment with trastuzumab. Among several ligands, the serum level of hepatocyte growth factor (HGF) was significantly lower in responders compared with that in non-responders (p = 0.014). Multivariate analyses showed that a high level of serum HGF was a poor prognostic factor for overall survival (OS) compared with low levels of HGF (adjusted HR: 3.857, 95% CI: 1.309–11.361, p = 0.014). Among 25 patients without initial disease progression on the treatment with trastuzumab, the mean value of serum HGF at disease progression was significantly higher than that at pre-treatment (p = 0.041). As novel findings, our study indicated that serum level of HGF was associated with tumor shrinkage and time to progression of trastuzumab in HER2-positive patients with metastatic GC.

Risk Factors for Esophageal Fistula Associated With Chemoradiotherapy for Locally Advanced Unresectable Esophageal Cancer: A Supplementary Analysis of JCOG0303

Abstract Esophageal fistula is a critical adverse event in patients treated with chemoradiotherapy (CRT) for locally advanced esophageal cancer. However, risk factors associated with esophageal fistula formation in patients receiving CRT have not yet been elucidated. We retrospectively analyzed data obtained from 140 patients who were enrolled in a phase II/III trial comparing low-dose cisplatin with standard-dose cisplatin administered in combination with 5-flurouracil and concomitant radiotherapy. Inclusion criteria were performance status (PS) 0 to 2 and histologically proven thoracic esophageal cancer clinically diagnosed as T4 and/or unresectable lymph node metastasis for which definitive CRT was applicable. Risk factors for esophageal fistula were examined with univariate analysis using Fisher exact test and multivariate analysis using logistic regression models. Esophageal fistula was observed in 31 patients (22%). Of these, 6 patients developed fistula during CRT. Median time interval between the date of CRT initiation and that of fistula diagnosis was 100 days (inter quartile range, 45–171). Esophageal stenosis was the only significant risk factor for esophageal fistula formation both in univariate (P = 0.026) and in multivariate analyses (odds ratio, 2.59; 95% confidence interval, 1.13–5.92, P = 0.025). Other clinicopathological factors, namely treatment arm, age, sex, PS, primary tumor location, T stage, lymph node invasion to adjacent organs, blood cell count, albumin level, and body mass index, were not risk factors fistula formation. Esophageal stenosis was a significant risk factor for esophageal fistula formation in patients treated with CRT for unresectable locally advanced thoracic esophageal squamous cell carcinoma.

Pretreatment Immune Status Correlates with Progression-Free Survival in Chemotherapy-Treated Metastatic Colorectal Cancer Patients

It was not clear whether immune cell subsets in peripheral blood have prognostic value for patients about to undergo first-line chemotherapy. This prospective study reveals an immune signature that correlates with significantly longer progression-free survival. It remains unclear whether the immunologic status of cells in peripheral blood can be used as a prognostic indicator of response to treatment for patients with unresectable metastatic colorectal cancer (MCRC). We therefore investigated the relationship between the pretreatment immunologic status of 40 patients with MCRC who planned to receive the first-line chemotherapy and their progression-free survival. Twenty-five immune cell subsets, including monocytic myeloid-derived suppressor cells (M-MDSC) and effector memory T cells (TEM), were measured by multicolor-flow cytometry. We divided patients into high and low (above and below the median, respectively) groups based on the median value for each immune cell subset and compared progression-free survival of the two groups. Patients with high M-MDSC, low CD4+ TEM, or low CD8+ TEM quantities had significantly shorter progression-free survival (P = 0.004, 0.005, and 0.002, respectively). Patients were classified into two prognostic groups based on numbers of adverse factors; having two or three adverse factors (n = 21, 52.5%) was correlated with significantly shorter progression-free survival compared with none or one (n = 19, 47.5%; P < 0.001). The presence of two or three adverse factors was an independent poor prognostic factor for progression-free survival (HR, 9.2; 95% confidence interval, 2.5–34.2; P < 0.001). These results provide evidence that pretreatment peripheral immune status can inform the outcome of patients with MCRC treated with first-line chemotherapy. Cancer Immunol Res; 4(7); 592–9. ©2016 AACR.

The peripheral immune status of granulocytic myeloid-derived suppressor cells correlates the survival in advanced gastric cancer patients receiving cisplatin-based chemotherapy

BACKGROUND The prognostic significance of peripheral immune status in patients with advanced gastric cancer (AGC) remains unclear. RESULTS From July 2013 through December 2014, 37 patients were enrolled. Among patients with 25 subsets of immune cells, patients in the high group of granulocytic myeloid-derived suppressor cells (Gr-MDSCs) showed significantly shorter progression-free survival (PFS) than those in the low group (3.98 vs. 8.78 months; hazards ratio (HR), 2.61; p = 0.01). In multivariate analysis, the high Gr-MDSCs value was also associated with shorter PFS (HR, 4.60; 95% confidence interval (CI), 1.79-11.8; p = 0.001). Although significant difference was not found in univariate analysis, the high Gr-MDSCs group was associated with shorter overall survival (OS) (HR, 2.89; 95% CI, 1.23-6.80; p = 0.015) in multivariate analysis. MATERIALS AND METHODS In this explorative prospective study, peripheral blood samples were collected from AGC patients before initiating first-line cisplatin-based chemotherapy (S-1 + cisplatin or S-1 + cisplatin + docetaxel). Peripheral blood mononuclear cells were analyzed for 25 immune subsets by multicolor flow cytometry. PFS and OS were compared between the patients divided into high and low (≥ and < median, respectively) groups based on the median value for each immune cell subset. CONCLUSIONS The peripheral immune status of Gr-MDSCs appears to affect the prognosis in AGC. Further research is needed to confirm the clinical value of the level of circulating Gr-MDSCs as a prognostic and/or predictive marker in AGC.Background The prognostic significance of peripheral immune status in patients with advanced gastric cancer (AGC) remains unclear. Results From July 2013 through December 2014, 37 patients were enrolled. Among patients with 25 subsets of immune cells, patients in the high group of granulocytic myeloid-derived suppressor cells (Gr-MDSCs) showed significantly shorter progression-free survival (PFS) than those in the low group (3.98 vs. 8.78 months; hazards ratio (HR), 2.61; p = 0.01). In multivariate analysis, the high Gr-MDSCs value was also associated with shorter PFS (HR, 4.60; 95% confidence interval (CI), 1.79−11.8; p = 0.001). Although significant difference was not found in univariate analysis, the high Gr-MDSCs group was associated with shorter overall survival (OS) (HR, 2.89; 95% CI, 1.23–6.80; p = 0.015) in multivariate analysis. Materials and Methods In this explorative prospective study, peripheral blood samples were collected from AGC patients before initiating first-line cisplatin-based chemotherapy (S-1 + cisplatin or S-1 + cisplatin + docetaxel). Peripheral blood mononuclear cells were analyzed for 25 immune subsets by multicolor flow cytometry. PFS and OS were compared between the patients divided into high and low (≥ and < median, respectively) groups based on the median value for each immune cell subset. Conclusions The peripheral immune status of Gr-MDSCs appears to affect the prognosis in AGC. Further research is needed to confirm the clinical value of the level of circulating Gr-MDSCs as a prognostic and/or predictive marker in AGC.

Association between serum ligands and the skin toxicity of anti‐epidermal growth factor receptor antibody in metastatic colorectal cancer

Skin toxicity is a known clinical signature used to predict the prognosis of anti‐epidermal growth factor receptor (EGFR) antibody treatment in metastatic colorectal cancer (mCRC). There are no biological markers to predict skin toxicity before anti‐EGFR antibody treatment in mCRC patients. Between August 2008 and August 2011, pretreatment serum samples were obtained from KRAS wild‐type (WT) patients who received anti‐EGFR antibody treatment. Serum levels of ligands were measured by ELISA. A total of 103 KRAS WT patients were enrolled in the study. Progression‐free survival and overall survival of patients with a high grade (grade 2–3) of skin toxicity were significantly longer than those with a low grade (grade 0–1) of skin toxicity (median progression‐free survival, 6.4 months vs 2.4 months, P < 0.001; median overall survival, 14.6 months vs 7.1 months, P = 0.006). There were significant differences in distribution of serum levels of epiregulin (EREG), amphiregulin (AREG), and hepatocyte growth factor (HGF) between groups of low/high grade of skin toxicity (P < 0.048, P < 0.012, P < 0.012, respectively). In addition, serum levels of HGF, EREG, and AREG were inversely proportional to grades of skin toxicity as determined by the Cochran–Armitage test (P = 0.019, P = 0.047, P = 0.021, respectively). Our study indicated that serum levels such as HGF, EREG, and AREG may be significant markers to predict the grade of skin toxicity and the prognosis of anti‐EGFR antibody treatment, which contribute to improvement of the management of skin toxicity and survival time in mCRC patients.

Prognostic role of ERBB2, MET and VEGFA expression in metastatic colorectal cancer patients treated with anti-EGFR antibodies

Background:High amplification of epiregulin (EREG) and amphireglin (AREG) in tumour tissues has been previously reported to be associated with better outcome in metastatic colorectal cancer (mCRC) patients who were treated with anti-EGFR antibodies. Here we investigated associations between the expression of other candidate prognostic biomarkers and outcome in mCRC patients receiving similar treatment.Methods:The relative mRNA levels of seven genes including ERBB2, MET, VEGFA, EREG, AREG, PTEN and ERCC1 between tumour (T) and non-tumour (NT) tissue sections were analysed by quantitative real-time PCR. Relative mRNA values, that is, T/NT ratios, of target genes were calculated and hazard ratios (HRs) for each gene of interest were adjusted for age, gender, performance status, minor RAS mutations and other clinicopathological variables which exhibited P-values<0.1 on the basis of univariate analysis.Results:Among 108 cases who received anti-EGFR antibodies, there were 96 cases of KRAS exon2 wild-type patients enroled in this study. When the cutoff values for relative mRNA levels were set to the upper 25th percentile of all patients, there were statistically significant differences in overall survival (OS) between the patients with high and low levels of EREG (HR: 0.326, 95% CI: 0.136–0.772, P=0.011), ERBB2 (HR: 1.31, 95% CI: 1.084–1.652, P=0.040), MET (HR: 2.48, 95% CI: 1.356–5.463, P=0.026), and VEGF-A (HR: 1.29, 95% CI: 1.036–1.606, P=0.046). In addition, patients with high ERBB2 had shorter progression-free survival (PFS) compared with low ERBB2 (HR: 1.98, 95% CI: 1.062–3.850). There were no significant differences in PFS and OS with respect to relative expression levels of PTEN and ERCC1. The prognostic role of AREG was evaluated in only T sections, as the mRNA expression level of this gene was mostly (91% cases) undetectable in NT sections. Patients with high AREG had longer OS compared with low AREG (HR: 0.227, 95% CI: 0.095–0.808).Conclusions:Our study has shown that higher T/NT ratios of ERBB2, MET and VEGFA mRNA were associated with worse OS in mCRC patients treated with anti-EGFR antibodies, with higher EREG and AREG were associated with better prognosis in the same setting. These findings will contribute the further understanding and management of anti-EGFR antibody treatment in mCRC patients.

Combined Assessment of Endothelial Growth Factor Receptor Dual Color In Situ Hybridization and Immunohistochemistry with Downstream Gene Mutations in Prediction of Response to the Anti-EGFR Therapy for Patients with Metastatic Colorectal Cancer

BACKGROUND AND AIMS Biomarkers associated with anti-EGFR antibodies therapy have been investigated in metastatic colorectal cancer (CRC). We conducted this study to evaluate the clinical utility of a combined assessment of EGFR status and genomic mutations of the EGFR downstream signal pathway in predicting the efficacy of anti-EGFR antibody treatment. METHODS We collected formalin-fixed paraffin-embedded tumor tissues and evaluated the EGFR status by immunohistochemistry (IHC), dual color in situ hybridization (DISH) and genomic analyses of KRAS, BRAF, PIK3CA and NRAS by direct sequencing. RESULTS A total of 129 patients were evaluated in our study. Among KRAS wild-type patients, EGFR DISH positivity was associated with a higher response rate than DISH negativity (56.3 vs. 21.1%, p = 0.011). A subgroup with EGFR DISH positivity plus IHC3+ and wild-type of EGFR downstream gene mutations achieved higher response rate and disease control rate. EGFR DISH positivity, KRAS codon 146 mutation and NRAS codon 61 mutation were prognostic factors in both progression-free survival and overall survival by multivariate analyses. CONCLUSIONS Combined assessment of DISH plus IHC and EGFR downstream gene mutations was useful to predict the response to anti-EGFR antibodies treatment in metastatic colorectal cancer patients in our study.

Phase I study of a new cancer vaccine of ten mixed peptides for advanced cancer patients

A phase I study of a new cancer vaccine (KRM‐10), consisting of a mixture of 10 different short peptides, was conducted for patients with advanced gastrointestinal cancers. Primary or secondary endpoints included the dose‐limiting toxicity (DLT), or safety and immune responses, respectively. Peptide‐specific cytotoxic T lymphocytes (CTL) and immunoglobulin G (IgG), together with soluble inflammatory factors, were measured before and after vaccination. Twenty‐one patients were vaccinated with KRM‐10 at dose levels of 10 (n = 6), 20 (n = 8) or 30 mg (n = 7) of peptides every week for 6 weeks. No DLT were observed in the dose range evaluated. Common treatment‐related adverse events were a grade 1 injection site reaction in 15 patients, and fever in three patients (grade 1 in two patients and grade 2 in one patient). CTL activity to at least one peptide at the time of the third and sixth vaccination increased in 2 and 3 of 6 (10 mg), 2 of 8 and 4 of 6 (20 mg), or 2 and 1 of 6 (30 mg) patients, respectively. IgG levels, at the third and sixth vaccination, were also increased in 1 and 1 of 6 (10 mg), 2 of 8 and 4 of 6 (20 mg), or 1 and 3 of 6 (30 mg) patients, respectively. The KRM‐10 vaccine consisting of 20 mg of peptides was determined as the optimal dose for a coming phase II trial because of its safety, and also for demonstrating the most potent activity for augmenting the immune response of the three doses tested. This trial was registered at the UMIN Clinical Trials Registry as UMIN000008820.