Circulating cell-free DNA methylation patterns as non-invasive biomarkers to monitor colorectal cancer treatment efficacy without referencing primary site mutation profiles.

This study investigates methylation patterns in circulating cell-free DNA (ccfDNA) for their potential role in colorectal cancer (CRC) detection and the monitoring of treatment response. Through methylation microarrays and quantitative PCR assays, we analyzed 440 samples from The Cancer Genome Atlas (TCGA) and an additional 949 CRC samples. We detected partial or extensive methylation in over 85% of cases within three biomarkers: EFEMP1, SFRP2, and UNC5C. A methylation score for at least one of the six candidate regions within these genes' promoters was present in over 95% of CRC cases, suggesting a viable detection method. In evaluating ccfDNA from 97 CRC patients and 62 control subjects, a difference in methylation and recovery signatures was observed. The combined score, integrating both methylation and recovery metrics, showed high diagnostic accuracy, evidenced by an area under the ROC curve of 0.90 (95% CI = 0.86 to 0.94). While correlating with tumor burden, this score gave early insight into disease progression in a small patient cohort. Our results suggest that DNA methylation in ccfDNA could serve as a sensitive biomarker for CRC, offering a less invasive and potentially more cost-effective approach to augment existing cancer detection and monitoring modalities, possibly supporting comprehensive genetic mutation profiling.

Genomically Stable Gastric Cancer Characterized by Hypomethylation in Wnt Signal Cascade.

INTRODUCTION: Gastric cancer is divided into four subtypes by their molecular features linked with genetic alterations, e.g., Epstein-Barr virus (EBV), microsatellite instability-high (MSI-high), chromosomal instability (CIN), and genomically stable (GS), called as TCGA classification. In this study, we tried to clarify the epigenetic features of the four GC subtypes according to aberrant methylation status in 23 loci. METHODS: A total of 98 gastric cancers and their normal gastric mucosa samples were included in this study. We divided gastric cancers into TCGA subtypes which were determined in line with MSI-high, EBV, CIN, to GS by their molecular features. The 13 loci of polymorphic microsatellite sequences were used to determine loss of heterogeneity for the detection of CIN. The MSI status was determined by three mononucleotide repeat markers. Infection of EBV was determined by recovering EBV BNRF1 sequence from genomic DNA collected from gastric cancers. Methylation status of 23 loci was investigated by the combined bisulfite restriction analysis. Status of other findings, e.g., KRAS mutations, HER2 expression status, and infection of helicobacter pylori were confirmed. RESULTS: Gastric cancers were divided into MSI (13%), EBV (7%), CIN (53%), and GS (27%). By histological classification, poorly differentiated adenocarcinoma was more in tumors categorized in MSI-high, and GS and signet-ring cell carcinoma (sig) were more in GS. Among the 23 loci investigated their methylation status, 18 loci were significantly hypermethylated in caner tissues. An unsupervised clustering divided gastric cancers into two clusters and revealed that most GS tumors clustered together in a cluster that exhibited lower methylation levels, distinct from the other subtypes. The inter-variable clustering revealed that a cluster contained the three loci (SFRP2-region 1/2 and APC) belonging to the Wnt signal cascade (Wnt-associated loci). The mean methylation score of Wnt-associated loci was the lowest in GS tumors (MSI-high: 2.7 [95% confidence interval, 2.3-2.9]; EBV: 2.1 [1.2-3.1]; CIN: 2.4 [2.2-2.7]; GS: 1.3 [0.8-0.7]). In contrast, the mean methylation score of the other 15 loci was significantly higher in MSI-high, while that in GS was as same as that in EBV or CIN (MSI-high: 10.4 [8.3-12.4]; EBV: 5.7 [1.7-9.7]; CIN: 4.4 [3.6-5.1]; GS: 3.4 [2.2-4.6]). Additionally, the lower methylation score of Wnt-associated loci was observed only in sig tumors. CONCLUSIONS: GS subtype tumors have the potential to possess distinct signatures in DNA hypomethylation profiles in Wnt signaling pathway, especially in sig.

Multicenter, single-arm, phase II study of the continuous use of panitumumab in combination with FOLFIRI after FOLFOX for RAS wild-type metastatic colorectal cancer: Exploratory sequential examination of acquired mutations in circulating cell-free DNA.

This multicenter single-arm, phase II study evaluated the efficacy and safety of uninterrupted panitumumab usage combined with cytotoxic doublets for unresectable/metastatic colorectal cancer (mCRC). Additionally, clinical value of the RAS/BRAF mutation status in circulating cell-free DNA (ccfDNA) was evaluated; this evaluation was measured independently of the protocol treatment. Eligible patients with RAS wild-type mCRC who had received the first-line panitumumab plus FOLFOX treatment were recruited and administered continuous panitumumab combined with FOLFIRI. Progression-free survival (PFS) at 6 months was the primary endpoint, with threshold and expected values of 35% and 50%, respectively. In total, 54 patients were enrolled between October 2017 and October 2019. The crude 6-month PFS rate was 37.0%, with a 4.8-month median PFS. The response rate and disease control rate were 16.7% and 50.0%, respectively. Notably, of the 54 participants, 17 showed RAS/BRAF mutations until the end of the protocol treatment and of the 22 patients with progressive disease as their best response, 10 possessed RAS/BRAF mutations in their plasma ccfDNA at baseline. The median PFS significantly differed among patients harboring tumors with BRAF and RAS mutations and those with wild-type tumors. In conclusion, our study failed to show the expected efficacy of the continuous panitumumab use in the second-line treatment. Liquid biopsy discriminated the duration of PFS according to the mutation status. The effectiveness of continuous treatment with panitumumab should be evaluated in patients with RAS/BRAF wild-type mCRC determined by liquid biopsy at the start of the second-line treatment.

Technique of vessel-skeletonized parenchyma-sparing hepatectomy for the oncological treatment of bilobar colorectal liver metastases.

BACKGROUND: To aid in the oncological management of multiple bilobar colorectal liver metastases (CRLMs), we describe a new surgical procedure, VEssel-Skeletonized PArenchyma-sparing Hepatectomy (VESPAH). STUDY DESIGN: Of 152 patients with CRLMs treated with hepatectomy, 33 patients had multiple bilobar liver metastases (≥8 liver metastases); their surgical procedures and clinical outcomes were retrospectively summarized and compared between those who underwent VESPAH and those who underwent major hepatectomy (Major Hx). RESULTS: Of the 33 patients, 20 patients were resected by VESPAH (the VESPAH group) and 13 patients by major hepatectomy (Major Hx group). The median number of CRLMs was 13 (range, 8-53) in the VESPAH group and 10 (range, 8-41) in the Major Hx group (P=0.511). No operative mortality nor severe morbidity was observed in either group. The VESPAH group showed earlier recovery of remnant liver function after surgery than the Major Hx group; the incidence of grade B/C post hepatectomy liver failure was 5% in the VESPAH group and 38% in the Major Hx group, P=0.048). Intrahepatic tumor recurrence was confirmed in 14 (70%) and 7 (54%) patients in the VESPAH and Major Hx groups, respectively (P=0.416). There was no significant difference in median overall survival (OS) after hepatectomy between the two groups; the median OS was 47 months in the VESPAH group and 33 months in the Major Hx group (P=0.481). The VESPAH group showed the higher induction rate of adjuvant chemotherapy within 2 months after surgery (P=0.002) and total number of repeat hepatectomy for intrahepatic recurrence (P=0.060) than the Major Hx group. CONCLUSIONS: VESPAH enables us to clear surgical navigation by hepatic vessel skeletonization and may enhance patient tolerability of not only adjuvant chemotherapy but also repeat hepatectomies during the patients' lifetimes.

A phase II study of FOLFOXIRI plus bevacizumab as initial chemotherapy for patients with untreated metastatic colorectal cancer: TRICC1414 (BeTRI).

PURPOSE: FOLFOXIRI plus bevacizumab is regarded as a first-line therapeutic option for selected patients with metastatic colorectal cancer (mCRC). Our aim was to assess the efficacy and safety of induction treatment with FOLFOXIRI plus bevacizumab in patients with untreated mCRC harboring UGT1A1 wild (*1/*1), or single-hetero (*1/*6 or *1/*28) genotypes. METHODS: Twelve cycles of FOLFOXIRI plus bevacizumab were administered to patients with untreated mCRC. The primary endpoint was the overall response rate (ORR) assessed by central independent reviewers. Secondary endpoints included time to treatment failure (TTF), progression-free survival (PFS), overall survival (OS), relative dose intensity (RDI), R0 resection rate, and safety. The exploratory objectives were early tumor shrinkage (ETS) and depth of response (DoR). RESULTS: Of the 47 patients enrolled, 46 and 44 patients were eligible for the safety and efficacy analysis, respectively. The primary endpoint was met. The ORR was 63.6% (95% CI 47.8-77.6). At a median follow-up of 25.4 months, median TTF, PFS, and OS was 8.1, 15.5, and 34.4 months, respectively. The median RDI of 5-fluorouracil, irinotecan, oxaliplatin, and bevacizumab was 72, 69, 62, and 71%, respectively. R0 resection rate was 22.7%. Grade 3 or higher adverse events (≥ 10%) included neutropenia (65.2%), febrile neutropenia (26.1%), leukopenia (23.9%), anorexia (10.9%), nausea (10.9%), and diarrhoea (10.9%). No treatment-related deaths were observed. ETS and DoR were 70.5 and 45.4%, respectively. CONCLUSIONS: FOLFOXIRI plus bevacizumab induction treatment of Japanese patients was shown to be beneficial and manageable, although caution is required since the treatment causes febrile neutropenia.

The PVT1 lncRNA is a novel epigenetic enhancer of MYC, and a promising risk-stratification biomarker in colorectal cancer.

Accumulating evidence suggests that dysregulation of transcriptional enhancers plays a significant role in cancer pathogenesis. Herein, we performed a genome-wide discovery of enhancer elements in colorectal cancer (CRC). We identified PVT1 locus as a previously unrecognized transcriptional regulator in CRC with a significantly high enhancer activity, which ultimately was responsible for regulating the expression of MYC oncogene. High expression of the PVT1 long-non-coding RNA (lncRNA) transcribed from the PVT1 locus was associated with poor survival among patients with stage II and III CRCs (p < 0.05). Aberrant methylation of the PVT1 locus inversely correlated with the reduced expression of the corresponding the PVT1 lncRNA, as well as MYC gene expression. Bioinformatic analyses of CRC-transcriptomes revealed that the PVT1 locus may also broadly impact the expression and function of other key genes within two key CRC-associated signaling pathways - the TGFß/SMAD and Wnt/ß-Catenin pathways. We conclude that the PVT1 is a novel oncogenic enhancer of MYC and its activity is controlled through epigenetic regulation mediated through aberrant methylation in CRC. Our findings also suggest that the PVT1 lncRNA expression is a promising prognostic biomarker and a potential therapeutic target in CRC.

[A New Era of Colorectal Cancer Treatment Being Led by a Precise Analysis of Somatic Mutational Profiles Including RAS, BRAF Mutation and Microsatellite Instability Status].

In Japan, clinically, a decade has passed since KRAS exon 2 hotspot mutations could be measured as a companion diagnostic agent of an anti-epidermal growth factor receptor antibody to treat unresectable advanced colorectal cancer. Till now, not only KRAS exon 2, but also KRAS exon 3, 4 and NRAS exon 2-4 mutation, and BRAF mutation(V600E)are approved as insurance as a companion diagnostics tool. In addition to those somatic mutations observed in Ras-Raf signal cascade, the measurement of microsatellite instability status is also approved as a companion diagnostic to anti-programmed death-1 receptor antibodies. Since these somatic mutational profiles in colorectal cancer cells are measured to determine the propriety of administration of a particular medicine, the results must be appropriately reflected in therapy for each patient. In this review, I will summarize the feature of clinical characteristics belonging to each somatic mutational profile commonly observed in colorectal cancer, and discuss howsuch somatic mutational profiles including RAS, BRAF mutation, and microsatellite instability status bring us to a newera of colorectal cancer.

Detection of circulating microRNAs with Ago2 complexes to monitor the tumor dynamics of colorectal cancer patients during chemotherapy.

Because of the different forms of circulating miRNAs in plasma, Argonaute2 (Ago2)-miRNAs and extracellular vesicles (EV-miRNAs), we examined the two forms of extracellular miRNAs in vitro and developed a unique methodology to detect circulating Ago2-miRNAs in small volumes of plasma. We demonstrated that Ago2-miR-21 could be released into the extracellular fluid by active export from viable cancer cells and cytolysis in vitro. As miR-21 and miR-200c were abundantly expressed in both metastatic liver sites and primary lesions, we evaluated Ago2-miR-21 as a candidate biomarker of both active export and cytolysis while Ago2-miR-200c as a biomarker of cytolysis in plasma obtained from colorectal cancer (CRC) patients before treatment and in a series of plasma obtained from CRC patients with liver metastasis who received systemic chemotherapy. The measurement of Ago2-miR-21 allowed us to distinguish CRC patients from subjects without CRC. The trend in ΔCt values for Ago2-miR-21 and -200c during chemotherapy could predict tumor response to ongoing treatment. Thus, capturing circulating Ago2-miRNAs from active export can screen patients with tumor burdens, while capturing them from passive release by cytolysis can monitor tumor dynamics during chemotherapy treatment.

Randomised phase II trial of mFOLFOX6 plus bevacizumab versus mFOLFOX6 plus cetuximab as first-line treatment for colorectal liver metastasis (ATOM trial).

BACKGROUND: Chemotherapy with biologics followed by liver surgery improves the resection rate and survival of patients with colorectal liver metastasis (CRLM). However, no prospective study has compared the outcomes of chemotherapy with bevacizumab (BEV) versus cetuximab (CET). METHODS: The ATOM study is the first randomised trial comparing BEV and CET for initially unresectable CRLM. Patients were randomly assigned in a 1:1 ratio to receive mFOLFOX6 plus either BEV or CET. The primary endpoint was progression-free survival (PFS). RESULTS: Between May 2013 and April 2016, 122 patients were enrolled. Median PFS was 11.5 months (95% CI 9.2-13.3 months) in the BEV group and 14.8 months (95% CI 9.7-17.3 months) in the CET group (hazard ratio 0.803; P = 0.33). Patients with a smaller-number but larger-sized metastases did better in the CET group. In the BEV and CET groups, the response rates were 68.4% and 84.7% and the resection rates were 56.1% and 49.2%, respectively. CONCLUSION: Although CET achieved a better response rate than BEV for patients with a small number of large liver metastases, both biologics had similar efficacy regarding liver resection and acceptable safety profiles. To achieve optimal PFS, biologics should be selected in accordance with patient conditions. TRIAL REGISTRATION: This trial is registered at ClinicalTrials.gov (number NCT01836653), and UMIN Clinical Trials Registry (UMIN-CTR number UMIN000010209).

The relationship between peripheral neuropathy and efficacy in second-line chemotherapy for unresectable advanced gastric cancer: a prospective observational multicenter study protocol (IVY).

BACKGROUND: Paclitaxel is used in second-line conventional chemotherapies to manage patients with unresectable advanced gastric cancer (GC). Paclitaxel-induced peripheral neuropathy is a known adverse event leading to treatment discontinuation. Additionally, oxaliplatin which causes irreversible peripheral neuropathy is now commonly used in first-line chemotherapy for advanced GC in Japan. Thus, examining the incidence of peripheral neuropathy with paclitaxel after oxaliplatin is necessary to improve the quality of life and outcomes of patients with advanced GC in the second-line treatment setting. METHODS: This prospective observational multicenter study, (which we named IVY study), will evaluate the degree of chemotherapy-induced peripheral neuropathy (CIPN) and the efficacy of second-line chemotherapy for unresectable advanced GC. A patient neurotoxicity questionnaire (PNQ) and the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) will be used to assess CIPN during the second-line treatment. The key eligibility criteria are as follows: 1) unresectable or recurrent GC histologically confirmed to be primary adenocarcinoma of the stomach, 2) age over 20 years, 3) Eastern Cooperative Oncology Group performance status score of 0-2, 4) written informed consent following full study information is provided to the patient, 5) progression or intolerance for first-line chemotherapy comprising fluorinated pyrimidine and platinum anticancer drugs (cisplatin or oxaliplatin) for advanced GC. 6) presence of evaluable lesions as confirmed using a computed tomography (CT) or magnetic resonance imaging. A total of 200 patients is considered to be appropriate for inclusion in this study. DISCUSSION: The results of this study will provide some information on CIPN with the sequential usage of oxaliplatin as first-line chemotherapy to paclitaxel as second-line chemotherapy in clinical practice. TRIAL REGISTRATION: This trial is registered in the University Hospital Medical Information Network's Clinical Trials Registry with the registration number UMIN000033376 (Registered 11 July 2018).

Risk Analysis for Invasive Fungal Infection after Living Donor Liver Transplantation: Which Patient Needs Potent Prophylaxis?

BACKGROUND: Invasive fungal infection (IFI) is associated with high mortality after living donor liver transplant (LDLT). The aim of this study was to identify the risk factors for post-LDLT IFI for early diagnosis and improvement of antifungal treatment outcome. METHODS: Risk analysis data were available for all 153 patients who underwent LDLT between January 2005 and April 2012. RESULTS: During the follow-up period (1,553 ± 73 days, range 20-2,946 days), 15 patients (9.8%) developed IFI classified as "proven" (n = 8) and "probable" (n = 7) with fungal pathogens including Candida spp. (n = 10), Aspergillus spp. (n = 4), and Trichosporon (n = 2). Of these patients, 7 patients with IFI died despite treatment. The 1-, 3-, and 5-year survival rates were lower in patients with IFI than those without IFI (66.7/59.3/44.4 vs. 90.4/85.7/81.8%, respectively; p = 0.0026). Multivariate analysis identified model for end-stage liver disease score of ≥26 (OR 16.0, p = 0.0012) and post-transplant acute kidney injury (RIFLE criteria I- or F-class; OR 4.87, p = 0.047) as independent risk factors for IFI. CONCLUSION: Preoperative recipients' status and postoperative kidney dysfunction can affect an occurrence of post-transplant IFI. These risk factors would be taken into consideration for designation of proper antifungal therapy.

Multicenter phase II study of biweekly CAPIRI plus bevacizumab as second-line therapy in patients with metastatic colorectal cancer (JSWOG-C3 study).

BACKGROUND: Triweekly capecitabine plus irinotecan (CAPIRI) was not a replacement for fluorouracil, leucovorin, and irinotecan (FOLFIRI) in the treatment of metastatic colorectal cancer (mCRC) because of the potential for greater toxicity. Recently, it has reported that mCAPIRI is well tolerated and non-inferior to FOLFIRI. In this study, we conducted a multicenter phase II trial to assess the efficacy and safety of biweekly CAPIRI plus bevacizumab as second-line chemotherapy for mCRC with reduced toxicity and preserved efficacy. METHODS: Patients with mCRC who had received prior chemotherapy, including oxaliplatin-based regimens, were eligible for this study. The treatment protocol administered capecitabine at 1000 mg/m2 twice daily from the evening of day 1 to the morning of day 8, intravenous irinotecan at 150 mg/m2 on day 1, and bevacizumab at 10 mg/kg on day 1 every 2 weeks. Primary endpoints for this study were progression-free survival (PFS) and safety. Secondary endpoints were overall survival (OS), time to treatment failure, response rate (RR), and disease control rate (DCR). RESULTS: Fifty-one patients were enrolled in this study. Median PFS was 5.5 months [95% confidence interval (CI) 4.23-7.40 months], and median OS was 13.5 months (95% CI 11.57-20.23 months). The RR was 14.6% (95% CI 6.5-28.4%), and the DCR was 66.7% (95% CI 51.5-79.2%). Hypertension was the most common Grade 3 adverse event (27.5%), followed by neutropenia (17.6%). Only two patients suffered from grade 3 hand-foot syndrome. CONCLUSIONS: In mCRC patients, biweekly CAPIRI + bevacizumab appears effective and feasible as a second-line chemotherapy with relatively low toxicities, and has potential as a useful substitute for FOLFIRI + bevacizumab.

Laparoscopic Rectosigmoid Colon Vaginoplasty in Male-to-Female Transsexuals: Experience in Japan.

Intestinal vaginoplasty has several advantageous features, such as scarless surgery, low incidence of contraction of the reconstructed vagina, maintenance of vaginal depth, spontaneous mucus production, and a low rate of complications. Therefore, this technique is becoming popular in many countries. Following the global trend, the demand for intestinal vaginoplasty for transsexuals is also increasing in Japan. However, there are few reports on intestinal vaginoplasty in Japan. In this study, we examined the safety and effectiveness of rectosigmoid colon vaginoplasty in the Japanese population. We retrospectively surveyed 18 male-to-female transsexuals who underwent laparoscopic rectosigmoid colon vaginoplasty at the Okayama University Hospital Gender Center between October 2012 and December 2017. One patient had developed an anastomotic leak and 2 patients experienced vaginal prolapse, which needed revision surgery. Both adverse outcomes were comparable with those from previous studies. The anastomotic leak was managed adequately with conservative treatment. To avoid vaginal prolapse, it is important to decide the length of the rectosigmoid segment so that a pull on it does not cause it to become lax, while excessive stress on the feeder vessels is avoided. Based on our study, we concluded that rectosigmoid vaginoplasty was a reliable technique in the Japanese population.

[Incidence of Catheter-Related Thrombosis in Patients with Long-Term Indwelling Central Venous Port Who Received Chemotherapies for Unresectable Advanced Digestive Cancers].

BACKGROUND: Most patients with unresectable advanced digestive cancers require placement of a fully implantable venous access port to facilitate safe delivery of anti-cancer drugs. Anti-VEGF therapies are commonly used even though they increase the risk of thrombosis. The objective of this study was to assess the incidence of radiologically confirmed catheter-related thrombosis(CRT)in patients with advanced digestive cancers. METHODS: We retrospectively reviewed 88 patients with advanced digestive cancers who had adapted implantable ports placed in our institution for chemotherapy. RESULTS: Thirty-nine patients were diagnosed with colorectal cancer, 26 with gastric cancer, 12 with pancreatic cancer, 8 with esophageal cancer, and 3 with other cancers. During follow-up, 22 patients(25%)received anti-VEGF therapies, while 66 patients(75%)did not. Four out of 88 patients(4.5%)had asymptomatic CRT. The incidence of CRT was the same(4.5%)regardless of whether the patient received anti-VEGF therapy. CONCLUSIONS: In patients with digestive cancers who had implantable venous access ports, the incidence of the CRT was 4.5% with no association with anti-VEGF therapies.

Novel evidence for a PIWI-interacting RNA (piRNA) as an oncogenic mediator of disease progression, and a potential prognostic biomarker in colorectal cancer.

BACKGROUND: Emerging evidence suggests that PIWI-interacting RNAs (piRNAs) may be important epigenetic regulators of gene expression in human cancers; however, their functional and clinical significance in colorectal cancer (CRC) remains unknown. METHODS: We performed piRNA expression profiling in paired cancer and normal tissues through small RNA-sequencing. The clinical significance of candidate piRNAs was investigated, and independently validated in 771 CRC patients from three independent cohorts. The biological function of piRNAs was characterized in cell lines, followed by identification and validation of downstream target genes in CRC tissues. RESULTS: We identified piR-1245 as a novel and frequently overexpressed noncoding RNA in CRC, and its expression significantly correlated with advanced and metastatic disease. Patients with high piR-1245 expression experienced significantly shorter overall survival, and multivariate analysis identified its expression to serve as an independent prognostic biomarker in CRC. Functionally, piR-1245 acts as an oncogene and promotes tumor progression, and gene expression profiling results identified a panel of downstream target-genes involved in regulating cell survival pathway. Based upon piRNA:mRNA sequence complementarity, we identified a panel of tumor suppressor genes (ATF3, BTG1, DUSP1, FAS,NFKBIA, UPP1, SESN2, TP53INP1 and MDX1) as direct targets of piR-1245, and successfully validated an inverse correlation between their expression and piR-1245 in CRC. CONCLUSIONS: We for the first time have identified the role for a PIWI-interacting noncoding RNA, piR-1245, as a novel oncogene and a potential prognostic biomarker in colorectal cancer.

Antitumor activity of pan-HER inhibitors in HER2-positive gastric cancer.

Molecularly targeted therapy has enabled outstanding advances in cancer treatment. Whereas various anti-human epidermal growth factor receptor 2 (HER2) drugs have been developed, trastuzumab is still the only anti-HER2 drug presently available for gastric cancer. In this study, we propose novel treatment options for patients with HER2-positive gastric cancer. First, we determined the molecular profiles of 12 gastric cancer cell lines, and examined the antitumor effect of the pan-HER inhibitors afatinib and neratinib in those cell lines. Additionally, we analyzed HER2 alteration in 123 primary gastric cancers resected from Japanese patients to clarify possible candidates with the potential to respond to these drugs. In the drug sensitivity analysis, both afatinib and neratinib produced an antitumor effect in most of the HER2-amplified cell lines. However, some cells were not sensitive to the drugs. When the molecular profiles of the cells were compared based on the drug sensitivities, we found that cancer cells with lower mRNA expression levels of IGFBP7, a tumor suppressor gene that inhibits the activation of insulin-like growth factor-1 receptor (IGF-1R), were less sensitive to pan-HER inhibitors. A combination therapy consisting of pan-HER inhibitors and an IGF-1R inhibitor, picropodophyllin, showed a notable synergistic effect. Among 123 clinical samples, we found 19 cases of HER2 amplification and three cases of oncogenic mutations. In conclusion, afatinib and neratinib are promising therapeutic options for the treatment of HER2-amplified gastric cancer. In addition to HER2 amplification, IGFBP7 might be a biomarker of sensitivity to these drugs, and IGF-1R-targeting therapy can overcome drug insensitiveness in HER2-amplified gastric cancer.

Accuracy of four mononucleotide-repeat markers for the identification of DNA mismatch-repair deficiency in solid tumors.

BACKGROUND: To screen tumors with microsatellite instability (MSI) arising due to DNA mismatch repair deficiency (dMMR), a panel of five quasi-monomorphic mononucleotide-repeat markers amplified in a multiplex PCR (Pentaplex) are commonly used. In spite of its several strengths, the pentaplex assay is not robust at detecting the loss of MSH6-deficiency (dMSH6). In order to overcome this challenge, we designed this study to develop and optimize a panel of four quasi-monomorphic mononucleotide-repeat markers (Tetraplex) for identifying solid tumors with dMMR, especially dMSH6. METHODS: To improve the sensitivity for tumors with dMMR, we established a quasi-monomorphic variant range (QMVR) of 3-4 bp for the four Tetraplex markers. Thereafter, to confirm the accuracy of this assay, we examined 317 colorectal cancer (CRC) specimens, comprising of 105 dMMR [45 MutL homolog (MLH)1-deficient, 45 MutS protein homolog (MSH)2-deficient, and 15 MSH6-deficient tumors] and 212 MMR-proficient (pMMR) tumors as a test set. In addition, we analyzed a cohort of 138 endometrial cancers (EC) by immunohistochemistry to determine MMR protein expression and validation of our new MSI assay. RESULTS: Using the criteria of ≥ 1 unstable markers as MSI-positive tumor, our assay resulted in a sensitivity of 97.1% [95% confidence interval (CI) = 91.9-99.0%] for dMMR, and a specificity of 95.3% (95% CI = 91.5-97.4%) for pMMR CRC specimens. Among the 138 EC specimens, 41 were dMMR according to immunohistochemistry. Herein, our Tetraplex assay detected dMMR tumors with a sensitivity of 92.7% (95% CI = 80.6-97.5%) and a specificity of 97.9% (95% CI = 92.8-99.4%) for pMMR tumors. With respect to tumors with dMSH6, in the CRC-validation set, Tetraplex detected dMSH6 tumors with a sensitivity of 86.7% (13 of 15 dMSH6 CRCs), which was subsequently validated in the EC test set as well (sensitivity, 75.0%; 6 of 8 dMSH6 ECs). CONCLUSIONS: Our newly optimized Tetraplex system will help offer a robust and highly sensitive assay for the identification of dMMR in solid tumors.

[Analysis of Fecal Cancer-Specific DNA to Detect Colorectal Neoplasia].

To screen colorectal cancers, fecal occult blood test(FOBT), conducted to detect occult blood present in the feces, has been shown to reduce colorectal cancer mortality in many large-scale colorectal cancer screening programs. However, the sensitivities of FOBT for early-stage colon cancer, colon cancer located at the right colon and colorectal adenoma tend to be low. Additionally, some colorectal cancers which could not detect by repeated FOBT screening are actually existed. Beyond those disadvantages, FOBT is the most promised colorectal cancer screening tool for large-scale cohort. To overcome the weak points of FOBT to screen colorectal tumors, the strategy for capturing and recovering tumor-derived DNA in feces has been developed and applied for clinical usage. In this study, we summarized the series of strategies for capturing and recovering fecal tumor-derived DNA to screen colorectal neoplasia.

[Introduction].

Time has come when oncology has met immunology. Immune checkpoint inhibitors(ICIs)are being approved as standard cancer treatments, day by day. ICIs, however, have serious immune-related adverse events(irAEs)in a diverse manner, requiring the establishment of team-approach system to manage irAEs. Here, irAEs are summarized and their managements are discussed.

[A Case of Laparoscopic Surgery Performed for Lynch Syndrome in a Patient Who Developed Cecal Cancer and Uterine Carcinosarcoma Synchronously].

A 51-year-old woman was referred to our hospitalfor treatment of endometrialcancer. She had 3 family members with colorectal cancer in the first degree. She was also diagnosed with advanced cecal cancer based on a preoperative examination. She underwent laparoscopic surgery, modified radical hysterectomy, and bilateral salpingo-oophorectomy for endometrial cancer, and ileocecal resection for cecal cancer simultaneously. Pathological examination of the uterine tumor revealed carcinosarcoma with carcinomatous and sarcomatous components. Since she fulfilled 4 of the revised Bethesda criteria, we suspected Lynch syndrome. Immunohistochemical analysis of mismatch repair proteins demonstrated the loss of MSH2/MSH6 expression in both cecalcancer and uterine carcinosarcoma tissues. Genetic testing by direct sequencing revealed a pathogenic germ line mutation of MSH2 in codon 2245 of exon 14, and she was definitively diagnosed with Lynch syndrome. Laparoscopic surgery is less invasive and would be useful for Lynch syndrome patients potentially requiring multiple surgeries or risk- reduction surgery.