Hiromi Kataoka’s research while affiliated with Nagoya City University and other places

172 Background: Anti-EGFR antibody is recommended as one of the standard treatments in patients with RAS wild-type advanced colorectal cancer (CRC). Few reports have evaluated low-frequency subclones of alterations in EGFR signaling pathway genes in plasma cell-free DNA (cfDNA) during anti-EGFR treatment in prospective cohort of advanced CRC patients. Methods: Key inclusion criteria of this study was as follows: 20 years old and over, performance status 0 to 2, metastatic or recurrent CRC (adenocarcinoma), RAS wild-type CRC diagnosed by PCR-rSSO using tumor tissue, no prior use of anti-EGFR antibody. Plasma samples were prospectively collected at pre-treatment, at 4, 10 weeks, every 10 weeks thereafter, and at the end of the anti-EGFR treatment. With QX200 Droplet Digital PCR platform, we analyzed hotspot mutations of KRAS, NRAS, BRAF, and PIK3CA and copy number (CN) variant of HER2 and MET using plasma samples of pre- and post-treatment as well as during treatment (limited to patients with any gene alterations at pre- and post-treatment). Results: Total 50 patients were registered in this study, but 3 patients were excluded because inclusion criteria were not met. Finally, 47 patients were included in full analysis set. In 15 patients (31.9%), genetic alterations including KRAS (G12G13: 10.1%, A59Q61: 2.2%), NRAS (G12G13: 2.2%, Q61: 2.1%), BRAF (V600: 6.4%) , PIK3CA (E545: 4.3%, H1047: 4.3%) , and HER2 (amplification: 6.5%) were detected in pre-treatment samples. Analysis of pre-treatment samples showed that response rates of patients with any gene alterations (N = 13) and that without any gene alterations (N = 29) were 30.8% and 58.6%, respectively (p = 0.095). When the cut-off of variant allele frequency (VAF) was set as 0.5% in patients with any gene mutations, the response rates for cases with VAF ≥0.5% (N = 6) and those with VAF < 0.5% (N = 7) were 0% and 57.1%, respectively (p = 0.049). Among 41 patients with detectable target lesions by CT scan, there was significant difference in percentage of best tumor shrinkage between patients with gene alterations and those without gene alterations (32.1% vs 10.5%, p = 0.037), when cut-off VAF of any gene mutations was set as 0.5% and cut-off CN of HER2 or MET was set as 4 at pre-treatment. Due to dynamics of each gene alteration in cfDNA during treatment, mutations of KRAS A59Q61, NRAS Q61, and MET amplification were characterized as acquired alterations which were newly detected after the administration of anti-EGFR antibodies. Conclusions: Our study demonstrated the clinical relevance of minor mutant subclones in EGFR signaling pathway genes in plasma for predicting response to anti-EGFR treatment. Although sample size of this study was small, preferable threshold for distinguishing responders from non-responders may be 0.5% as VAF of these gene mutations. Clinical trial information: 000034923 .

The molecular and clinical characteristics of non‐ampullary duodenal adenomas and intramucosal adenocarcinomas are not fully understood because they are rare. To clarify these characteristics, we performed genetic and epigenetic analysis of cancer‐related genes in these lesions. One‐hundred seven non‐ampullary duodenal adenomas and intramucosal adenocarcinomas, including 100 small intestinal type tumors (90 adenomas and 10 intramucosal adenocarcinomas) and 7 gastric type tumors (2 pyloric gland adenomas and 5 intramucosal adenocarcinomas), were investigated. Using bisulfite pyrosequencing, we assessed the methylation status of CpG island methylator phenotype (CIMP) markers and MLH1 . Then using next‐generation sequencing, we performed targeted exome sequence analysis within 75 cancer‐related genes in 102 lesions. There were significant differences in the clinicopathological and molecular variables between small intestinal and gastric type tumors, which suggests the presence of at least two separate carcinogenic pathways in non‐ampullary duodenal adenocarcinomas. The prevalence of CIMP‐positive lesions was higher in intramucosal adenocarcinomas than adenomas. Thus, concurrent hypermethylation of multiple CpG islands is likely associated with development of non‐ampullary duodenal intramucosal adenocarcinomas. Mutation analysis showed that APC was the most frequently mutated gene in these lesions (56/102; 55%), followed by KRAS (13/102; 13%), LRP1B (10/102; 10%), GNAS (8/102; 8%), ERBB3 (7/102; 7%), and RNF43 (6/102; 6%). Additionally, the high prevalence of diffuse or focal nuclear β‐catenin accumulation (87/102; 85%) as well as mutations of WNT pathway components (60/102; 59%) indicate the importance of WNT signaling to the initiation of duodenal adenomas. The higher than previously reported frequency of APC gene mutations in small bowel adenocarcinomas as well as the difference in the APC mutation distributions between small intestinal type adenomas and intramucosal adenocarcinomas may indicate the adenoma‐carcinoma sequence has only limited involvement in duodenal carcinogenesis. This article is protected by copyright. All rights reserved.

Recent studies have shown that colorectal serrated lesions, which include sessile serrated adenomas (SSAs) and traditional serrated adenomas (TSAs), are precursors of colorectal cancer. However, the molecular mechanisms underlying the carcinogenesis, particularly in TSAs, remain largely uncharacterized. To clarify their molecular and clinicopathological characteristics, we performed mutation and methylation analyses of cancer-associated genes in 78 serrated lesions, including TSAs, SSAs and microvesicular hyperplastic polyps. Target exon sequence analysis was performed with 39 genes, including genes known to be frequently mutated in colorectal cancers and/or serrated lesions. We also used bisulfite pyrosequencing to assess the methylation status of various cancer-associated genes and marker genes of the CpG island methylator phenotype (CIMP). The prevalence of mutations in genes associated with Wnt signaling was significantly higher in TSAs than SSAs (65% vs. 28%, p < 0.01). Among those, RNF43 mutations were observed in 38% of TSAs and 17% of SSAs. In immunohistochemical studies of 39 serrated lesions, the prevalence of abnormal nuclear β-catenin accumulation was significantly higher in TSAs (57%) than SSAs (8%) (P = 0.01). SMOC1 methylation was detected in 54% of TSAs but in no SSAs (p < 0.01). Additionally, SMOC1 methylation was more prevalent among TSAs with KRAS mutation (82%) than with BRAF mutation (38%, p = 0.03). Lesions with CIMP-high or RNF43 mutations were detected only in TSAs with BRAF mutation, suggesting two distinct carcinogenic pathways in TSAs. Mutations in genes associated with Wnt signaling play a greater role in the carcinogenesis of TSAs than SSAs.

Since a fecal occult blood test for colorectal cancer (CRC) does not offer sufficient diagnostic power for CRC, novel non-invasive biomarkers are hopeful for CRC screening. We conducted the current study to discover non-invasive urinary biomarkers for diagnosing CRC. Among urine samples from 258 patients (CRC, n = 148; healthy controls, n = 110), a cohort of 176 patients composed of 88 patients with GC and 88 healthy controls was selected after age- and sex-matching using propensity score. This cohort was then randomly divided into 2 groups: 53 pairs (106 patients) in the training cohort, and 35 pairs (70 patients) in the validation cohort. No significant differences were found for baseline characteristics between the CRC and healthy control groups in both training and validation cohorts. On multivariate analysis in the training cohort, urinary levels of cysteine-rich protein 61 (uCyr61) and trefoil factor 3 (uTFF3) were identified as independent significant diagnostic markers for CRC. Moreover, uCyr61 alone and the combination of uCyr61 and uTFF3 allowed significant differentiation between healthy controls and CRC groups in the training set (uCyr61: area under the curve (AUC) = 0.745 [95% CI, 0.653–0.838]; uCyr61 + uTFF3: AUC = 0.753 [95% CI, 0.659–0.847]). In the validation cohort, uCyr61 and uTFF3 were significantly higher in the CRC group than in the healthy control group, and they also allowed significant differentiation between healthy control and CRC groups (uCyr61: AUC = 0.696 [95% CI, 0.571–0.822]; uTFF3: AUC = 0.639 [95% CI, 0.508–0.770]; uCyr61 + uTFF3: AUC = 0.720 [95% CI, 0.599–0.841]), as in the training cohort. A panel combining uCyr61 and uTFF3 offers a promising non-invasive biomarker for diagnosing CRC.

We describe a case of intestinal obstruction caused by a small bowel adenocarcinoma misdiagnosed as psychogenic disorder. A woman in her 40s was admitted to Nagoya City University Hospital with fatigue, anorexia, nausea and vomiting. CT, oesophagogastroduodenoscopy and colonoscopy revealed no signs of organic abnormality in her gastrointestinal tract. As the patient had previously been diagnosed with and treated for depression, her symptoms were suspected to be due to psychogenic disorder. Therefore, she was diagnosed with severe depression and was administered antidepressant agents. Despite intense psychiatric treatment, her symptoms worsened and she was later diagnosed with ileus due to adenocarcinoma in the jejunum. After drainage by insertion of a transnasal decompression tube, a partial jejunum resection was performed. After the resection, the patient’s symptoms including fatigue and depression resolved without the use of antidepressant agents.

Herein, we describe a rare case of refractory gastric antral ulcers. A woman in her 50 s was admitted to Nagoya City University Hospital with epigastric pain after being diagnosed with gastric antral submucosal tumor at another hospital. Findings from esophagogastroduodenoscopy and endoscopic ultrasound examination revealed that the lesion was a gastric ulcer. The patient had no Helicobacter pylori infection and no recent history of using non-steroidal anti-inflammatory drugs. On the basis of these findings, we diagnosed this as a case of refractory gastric antral ulcer (RGAU). RGAU is considered a new disease concept and detailed analyses are expected in the future.

The aim of this study was to evaluate the effects of oral administration of transglucosidase (TG) on postprandial glucose concentrations in healthy subjects. A randomized placebo-controlled three-way crossover trial was separated by a washout period of more than 3 days. Twenty-one normal healthy volunteers, aged 30-61 years old (17 males and 4 females) were selected for this study. The subjects' health was assessed as normal by prestudy screening. All subjects received 3 types of test meals (3 rice balls: protein, 14.4 g; fat, 2.1 g; and carbohydrate, 111 g: total energy, 522 kcal) with 200 ml water in which 0 mg, 150 mg, or 300 mg of TG was dissolved. Blood samples for estimating plasma glucose and insulin concentrations were collected before and every 30 min after the experiment. As compared to no TG treatment, TG administration tended to prevent a postprandial increase in plasma glucose (p = 0.069: 150 mg of TG vs control) but there were no significant difference among three groups. With regard to the 17 subjects who were suggested to have impaired glucose tolerance, TG significantly decreased the postprandial blood glucose (p<0.05: 150 mg and 300 mg of TG vs control) and marginally decreased insulin concentrations (p = 0.099: 300 mg of TG vs control). These results suggest that TG may be useful for preventing the progression of type 2 diabetes mellitus.