Simultaneous activation of Kras-Akt and Notch pathways induces extrahepatic biliary cancer via the mTORC1 pathway.

Biliary tract cancer (BTC) has poor prognosis. The Notch receptor is aberrantly expressed in extrahepatic cholangiocarcinoma (eCCA). However, the role of Notch signaling in the initiation and progression of eCCA and gallbladder (GB) cancer remains unknown. Therefore, we investigated the functional role of Notch signaling during tumorigenesis of the extrahepatic bile duct (EHBD) and GB. Activation of Notch signaling and oncogenic Kras resulted in the development of biliary intraepithelial neoplasia (BilINs) in the EHBD and GB, which were premalignant lesions that progressed to adenocarcinoma in mice. The expression of genes involved in the mTORC1 pathway was increased in biliary spheroids from Hnf1b-CreERT2; KrasLSL-G12D ; Rosa26LSL-NotchIC mice and inhibition of the mTORC1 pathway suppressed spheroid growth. Additionally, simultaneous activation of the PI3K-AKT and Notch pathways in EHBD and GB induced biliary cancer development in mice. Consistent with this, we observed a significant correlation between activated NOTCH1 and phosphorylated Ribosomal Protein S6 (p-S6) expression in human eCCA. Furthermore, inhibition of the mTORC1 pathway suppressed the growth of Notch-activated human biliary cancer cells in vitro and in vivo. Mechanistically, the Kras/Notch-Myc axis activated mTORC1 through TSC2 phosphorylation in mutant biliary spheroids. These data indicate that inhibition of the mTORC1 pathway could be an effective treatment strategy for Notch-activated human eCCA. © 2023 The Pathological Society of Great Britain and Ireland.

Loss of Arid1a and Pten in Pancreatic Ductal Cells Induces Intraductal Tubulopapillary Neoplasm via the YAP/TAZ Pathway.

BACKGROUND & AIMS: Pancreatic ductal adenocarcinoma (PDAC) arises from several types of premalignant lesions, including intraductal tubulopapillary neoplasm (ITPN); however, the molecular pathogenesis of ITPN remains unknown. METHODS: We performed studies with Hnf1b-CreERT2; Ptenf/f; Arid1af/f mice to investigate the consequence of genetic deletion of Arid1a in adult pancreatic ductal cells in the context of oncogenic PI3K/Akt pathway activation. RESULTS: Simultaneous deletion of Arid1a and Pten in pancreatic ductal cells resulted in the development of ITPN, which progressed to PDAC, in mice. Simultaneous loss of Arid1a and Pten induced dedifferentiation of pancreatic ductal cells and Yes-associated protein 1/Transcriptional coactivator with PDZ-binding motif (YAP/TAZ) pathway activation. Consistent with the mouse data, TAZ expression was found elevated in human ITPNs and ITPN-derived PDACs but not in human intraductal papillary mucinous neoplasms, indicating that activation of the TAZ pathway is a distinctive feature of ITPN. Furthermore, pharmacological inhibition of the YAP/TAZ pathway suppressed the dedifferentiation of pancreatic ductal cells and development of ITPN in Arid1a and Pten double-knockout mice. CONCLUSION: Concurrent loss of Arid1a and Pten in adult pancreatic ductal cells induced ITPN and ITPN-derived PDAC in mice through aberrant activation of the YAP/TAZ pathway, and inhibition of the YAP/TAZ pathway prevented the development of ITPN. These findings provide novel insights into the pathogenesis of ITPN-derived PDAC and highlight the YAP/TAZ pathway as a potential therapeutic target.

[A Case of Transverse Colon Cancer Associated with Lynch Syndrome with Excellent Response to Pembrolizumab].

A 47-year-old woman diagnosed with transverse colon cancer with liver, peritoneal, and lymph node metastases was admitted. Modified FOLFOX6(mFOLFOX6)regimen was given as a first line chemotherapy and was followed by pembrolizumab after 1 cycle of the mFOLFOX6, because microsatellite instability(MSI)test of the tumor showed high-frequency MSI. Because of the transverse colon obstruction after 2 cycles of pembrolizumab, she underwent right hemicolectomy. Histological examination of the resected specimen revealed no residual tumor cells in the primary tumor and reginal lymph nodes. Immunohistochemistry for mismatch repair proteins(IHC-MMR)showed loss of MSH2 and MSH6 expression. Genetic test identified a MSH2 pathogenic variant leading to the diagnosis of Lynch syndrome. The present case shows the importance of MSI test or IHC-MMR before the treatment of metastatic colorectal cancer.

[A Rare Case of Cronkhite-Canada Syndrome Associated with Gastric Cancer and Gastric Outlet Obstruction].

Cronkhite-Canada syndrome(CCS)is a rare non-inherited disease characterized by gastrointestinal polyposis and ectodermal abnormalities. We report a rare case of CCS associated with gastric cancer and gastric outlet obstruction with a review of the literature. A 75-year-old man was admitted because of frequent vomiting and hypoproteinemia. He was diagnosed with CCS due to typical clinical and laboratory findings including alopecia, nail atrophy, hypoproteinemia, and typical gastrointestinal polyposis. Upper endoscopic examination also pointed out a large gastric cancer mainly located in the antrum and the reversible pyloric obstruction caused by the gastric tumor. Biopsy of the tumor revealed tubular adenocarcinoma. Computed tomography demonstrated the dilated duodenum caused by packing of the gastric tumor. 1.5 months after prednisolone therapy, he underwent total gastrectomy with complete resection of the dilated duodenal bulb. Histological examination revealed gastric cancer(pap>tub1)classified into Stage ⅢC. Postoperative course was uneventful and he moved to another hospital. To our knowledge, including the present case, there were 20 reported cases of CCS associated with gastric cancer from Japan(1979-2022). Also, 7 cases of CCS associated with gastric outlet obstruction was reported.

JNK pathway plays a critical role for expansion of human colorectal cancer in the context of BRG1 suppression.

Tumor stem cells (TSCs), capable of self-renewal and continuous production of progeny cells, could be potential therapeutic targets. We have recently reported that chromatin remodeling regulator Brg1 is required for maintenance of murine intestinal TSCs and stemness feature of human colorectal cancer (CRC) cells by inhibiting apoptosis. However, it is still unclear how BRG1 suppression changes the underlying intracellular mechanisms of human CRC cells. We found that Brg1 suppression resulted in upregulation of the JNK signaling pathway in human CRC cells and murine intestinal TSCs. Simultaneous suppression of BRG1 and the JNK pathway, either by pharmacological inhibition or silencing of c-JUN, resulted in even stronger inhibition of the expansion of human CRC cells compared to Brg1 suppression alone. Consistently, high c-JUN expression correlated with worse prognosis for survival in human CRC patients with low BRG1 expression. Therefore, the JNK pathway plays a critical role for expansion and stemness of human CRC cells in the context of BRG1 suppression, and thus a combined blockade of BRG1 and the JNK pathway could be a novel therapeutic approach against human CRC.

Brg1 is required to maintain colorectal cancer stem cells.

Tumor cells capable of self-renewal and continuous production of progeny cells are called tumor stem cells (TSCs) and are considered to be potential therapeutic targets. However, the mechanisms underlying the survival and function of TSCs are not fully understood. We previously reported that chromatin remodeling regulator Brg1 is essential for intestinal stem cells in mice and Dclk1 is an intestinal TSC marker. In this study, we investigated the role of Brg1 in Dclk1+ intestinal tumor cells for the maintenance of intestinal tumors in mice. Specific ablation of Brg1 in Dclk1+ intestinal tumor cells reduced intestinal tumors in ApcMin mice, and continuous ablation of Brg1 maintained the reduction of intestinal tumors. Lineage tracing in the context of Brg1 ablation in Dclk1+ intestinal tumor cells revealed that Brg1-null Dclk1+ intestinal tumor cells did not give rise to their descendent tumor cells, indicating that Brg1 is essential for the self-renewal of Dclk1+ intestinal tumor cells. Five days after Brg1 ablation, we observed increased apoptosis in Dclk1+ tumor cells. Furthermore, Brg1 was crucial for the stemness of intestinal tumor cells in a spheroid culture system. BRG1 knockdown also impaired cell proliferation and increased apoptosis in human colorectal cancer (CRC) cells. Microarray analysis revealed that apoptosis-related genes were upregulated and stem cell-related genes were downregulated in human CRC cells by BRG1 suppression. Consistently, high BRG1 expression correlated with poor disease-specific survival in human CRC patients. These data indicate that Brg1 plays a crucial role in intestinal TSCs in mice by inhibiting apoptosis and is critical for cell survival and stem cell features in human CRC cells. Thus, BRG1 represents a new therapeutic target for human CRC. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

[A Case of Carcinoma of the Ileostomy Site Associated with Familial Adenomatous Polyposis-Report of a Case].

We report a rare carcinoma of the permanent ileostomy site developing 20 years or more after total proctocolectomy (TPC)in a 65-year-old woman with familial adenomatous polyposis(FAP). She underwent TPC for rectal cancer associated with FAP in her 40th at other institution. She also underwent pancreas-sparing total duodenectomy for duodenal mucosal cancer associated with severe duodenal polyposis at 59 years at our institution. She was referred to our hospital again complaining of the mass of the ileostomy site, 10 cm in diameter. Though biopsy revealed no definite malignancy, serum CA19-9 was elevated(98 U/mL), leading to a preoperative diagnosis to be ileal carcinoma. The involved bowel was widely resected. Histological examination demonstrated Stage ⅡA ileal carcinoma. Postoperative course was uneventful and she is well without recurrence 7 months after the ileal resection. This case seems valuable in that long-term surveillance including ileal carcinoma is important in the management of FAP patients whose colorectal cancer and duodenal cancer have been already well controlled.

[Idea of Treatment Method for Upper and Lower Rectal Cancer Avoiding Irradiation to Internal and External Sphincter].

BACKGROUND: Preoperative chemoradiotherapy(CRT)followed by total mesorectal excision(TME)is used for locally advanced rectal cancer, but it can induce postoperative anorectal function. The primary objective of this study is to confirm the efficacy and safety of preoperative CRT and TME without irradiation to the internal and external sphincter muscles. SUBJECTS AND METHODS: Patients were eligible for this study if they met the following inclusion criteria: histologically proven rectal cancer, clinical T3T4N0-2 disease, and a distance between anal margin of tumor and the rental line is more than 2 cm. Twelve patients who underwent preoperative CRT and TME between 2013 and 2017 were enrolled. The primary endpoint was completion rate of sphincter-preserving surgery. RESULTS: All patients completed preoperative CRT without Grade 3 or higher adverse effect. Sphincter-preserving surgery was performed in all cases. The 5-year disease-free survival rate was 46.7%, and the local recurrence-free survival rate was 75%, and the overall survival rate was 90.9%. CONCLUSION: It is suggested that preoperative CRT and TME without irradiation to the internal and external sphincter muscles is effective and safe therapy for locally advanced rectal cancer.

[A Case of Synchronous Gallbladder Metastasis Originating from Advanced Gastric Cancer].

Gallbladder metastasis from gastric cancer is often found accidentally during postoperative pathological examinations, and its preoperative diagnosis is very difficult. There are a few reports in diagnostic imaging, and it is well known to have a very poor prognosis. There have been 13 reports on gallbladder metastasis from gastric cancer in the Japanese literature. Among the 13 reports, 10 cases were diagnosed with gallbladder metastasis synchronously and only 1 case was diagnosed as gallbladder metastasis before surgery. One case was reported as hematogenous metastasis, and 9 cases were reported as lymphoid metastasis. In total, 7 patients died, all within the first year after surgery. We experienced a case of synchronous gallbladder metastasis from gastric cancer.

[The Outcome of Preoperative Chemoradiotherapy for Advanced Lower Rectal Cancer-The Possibility of an Omission of the Lateral Dissection].

The objective of this study was to evaluate the outcomes of selective LPLN dissection(LPLD)based on pretreatment imaging in patients with advanced low rectal cancer treated with pre-operative CRT. We reviewed 32 patients without suspected LPLN metastasis based on the MDCT or MRI results before CRT. These patients underwent total mesorectal excision (TME)without LPLD. The clinical characteristics and oncological outcomes were examined. In all cases, the per-protocol treatments were completed. Tumor recurrence occurred in 14 patients at the liver(3 cases), the lung(7 cases)and the local sites(4 cases). Of the 4 cases with pelvic recurrence, no recurrence was found in the lateral lymph node area. Under the condition that pre-operative chemoradiotherapy is to be performed for advanced lower rectal cancer with negative lateral lymph node metastasis, a lateral dissection could be omitted.

[Analysis of Palliative Stents for Colonic Stenosis Due to Extracolonic Cancers].

We retrospectively reviewed 13 patients in whom endoscopic stenting for colonic stenosis due to extracolonic cancers(non- CRC group)was attempted between July 2012 and January 2018. There were 5 men and 8 women, with a median age of 69 years. Primary malignancies causing colonic stenosis were gastric cancer(n=4), cholangiocarcinoma(n=2), pancreatic cancer(n=2), lung cancer(n=2), uterine cancer(n=2), and ovarian cancer(n=1). The non-CRC group patients demonstrated a significantly lower technical success rate than those who received palliative stents for colonic stenosis for primary colorectal cancer(n=51)(69% vs 98%, p<0.01). In addition, the non-CRC group patients(n=13)also demonstrated a significantly lower technical success rate(69% vs 99%, pp<0.01)than those who received stents aiming to subsequently undergo a bridge to surgery. Nonetheless, colorectal stenting for extracolonic malignancies appears to be a minimally invasive treatment and could offer patients rapid relief. Thus, it could be an effective alternative to some palliative therapies.

[Status of Hepatic Lymph Node Involvement in Patients with Resectable Liver Metastasis of Colorectal Cancer after Preoperative Chemotherapy].

The liver is the most common metastatic site for colorectal cancer(CRC).The 5-year survival rate of resected cases has been reported to be about 40%.Hepatic lymph node metastasis is reportedly associated with a poor prognosis in patients with liver metastases of CRC.The incidence of hepatic lymph node involvement in patients with liver metastases of CRC ranges from 5% to 28%.However, few reports have focused on hepatic lymph node involvement in patients with resectable liver metastasis who have undergone preoperative chemotherapy.This retrospective study was undertaken to address this issue.The subjects were 33 consecutive patients who had undergone the resection of liver metastases of CRC with hepatic lymph node sampling after preoperative chemotherapy between 2001 and 2016. Hepatic lymph node metastasis was confirmed in only one patient(3%).There was no significant difference in the frequency of hepatic lymph node metastasis between the cases with or without preoperative chemotherapy.The further collection of data is warranted to elucidate the significance of hepatic lymph node involvement in patients with liver metastases of CRC treated with preoperative chemotherapy.

[A Case of Giant Retroperitoneal Liposarcoma Resected after Trabectedin Chemotherapy].

The basic treatment for retroperitoneal liposarcoma is surgical therapy. Since the administration of trabectedin for soft tissue sarcoma has been approved, another option for soft tissue sarcoma treatment has been added. We report a case of radical resection after trabectedin therapy for initially unresectable retroperitoneal liposarcoma. A 61-year-old man was admitted to our hospital with an abdominal tumor. A tumor, about 50 cm in maximal diameter, that was not movable throughout the abdomen was observed. Computed tomography revealed a giant tumor almost occupying the entire abdomen, and he was diagnosed with retroperitoneal liposarcoma based on histopathological examination of a puncture specimen. Chemotherapy containing trabectedin was administered. At the end of 8 courses, he achieved stable disease. However, the movability improved, and surgery was performed. The procedure was tumor resection with right kidney, adrenal gland, and inferior vena cava resection. Histopathological examination revealed a mixed type of well differentiated type and dedifferentiated type. The patient is alive without recurrence 10 months after the surgery.

[Does the Sidedness of Perforative Colorectal Cancer Influence the Prognosis of Patients ?]

We examined the influence of the sidedness of the primary tumor on survival of patients with colon cancer perforation. The subjects of this retrospective study were 52 patients who underwent surgery for colon perforation between April 2005 and December 2016 at our institution and survived more than 30 days. Patients with perforation of the oral side of the tumor were included. The background data and survival times were compared between 9 patients whose primary tumors were located in the cecum, ascending colon, or transverse colon(right-side group)and 43 patients whose primary tumors were located in the descending colon, sigmoid colon, or rectum(left-side group). There was no significant difference in terms of age, sex, Stage, or rate of chemotherapy, but Hinchey stage was significantly higher in the left-side group(p<0.05). The median survival time tended to be longer in the left-side group(68.2 months vs 21.2 months, p=0.05). These results suggest that right-side perforation might cause a poorer prognosis than left-side perforation in patients with perforative colorectal cancer.

[Prognostic Impact of Tumor Location of Colorectal Cancer in Patients with Resected Liver Metastasis].

Recently, metastatic colorectal cancer(CRC)patients with a left-side primary tumor have been reported to have a significantly longer survival period than those with a right-side primary tumor. However, the impact of the location of the primary lesion on the survival outcomes of patients with resectable liver metastases of CRC has not yet been fully investigated. The subjects of this retrospective study were 113 consecutive patients who underwent a hepatic metastatectomy for CRC between 2001 and 2016 at our institution. The background data and survival times were compared between 32 patients whose primary lesions were located in the cecum or the ascending colon(right-side group)and 81 patients whose primary lesions were located in the descending colon, sigmoid colon, or rectum(left-side group). No significant differences in various clinicopathological variables were observed between the 2 groups. The 5-year overall and relapse-free survival rates after hepatectomy were 62.1% for the right-side group vs 49.2% for the left-side group(p=0.55)and 37.1% for the right-side group vs 33.4%for the left-sided group(p=0.76), respectively. In conclusion, colorectal liver metastasis should be resected regardless of the primary tumor location.

[A Case of Local Recurrence with Negative FDG/PET Findings after a Total Proctocolectomy for Ulcerative Colitis Associated with Colon Cancer with Retroperitoneal Penetration].

We report the case of a 55-year-old man who successfully underwent resection of a recurrence of ulcerative colitis(UC)- associated colon cancer located in the pancreatic body and left kidney. The patient had undergone an emergency laparotomy (total proctocolectomy with stapled ileal-pouch anal anastomosis)for the treatment of a descending colon cancer with retroperitoneal penetration associated with UC at the age of 50 years. At that time, histological examinations revealed a mucinous carcinoma that was classified as Stage II colon cancer. Three years after the patient's initial operation, a CT scan revealed a small mass located between the pancreatic tail and the left kidney. However, the accumulation of FDG was not observed during a positron emission tomography(PET)examination, resulting in close observation. As the size of the tumor and the levels of serum carcinoembryonic antigen and carbohydrate antigen 19-9 gradually increased, recurrence was highly suspected. A distal pancreatectomy and left nephrectomy were performed. Pathological examination showed findings concurrent with a local recurrence of colon cancer. Special histological types, such as mucinous carcinoma, often occur in some colitic cancers. For the postoperative surveillance of patients with colitic cancer, it should be noted that the sensitivity of FDG/PET is lower for mucinous carcinoma of the colon than it is for more common colon cancers.

[A Case of Advanced Gastric Cancer Successfully Treated with Curative Conversion Surgery after Chemotherapy with S-1 plus Oxaliplatin].

This report describes a patient with unresectable advanced gastric cancer who was successfully treated with potentially curative conversion surgery after chemotherapy with S-1 plus oxaliplatin(SOX). An 82-year-old man was diagnosed with type 5 gastric cancer(por1, HER2-negative)with multiple granular mucosal necroses that had metastasized throughout his body. Computed tomography revealed multiple lymph node metastases, tumor thrombosis in the splenic and portal veins, and peritoneal dissemination. After 9 courses of first-line chemotherapy with SOX, there was no tumor thrombosis in the splenic and portal veins or peritoneal dissemination, and the primary tumor and lymph node metastases were markedly reduced in size, indicative of a partial response(PR). The patient subsequently underwent total gastrectomy as curative conversion surgery. The histological diagnosis was ypT2N0M0, ypStage I B, and the primary lesion was categorized as Grade 2 gastric cancer. At present, 1 year after surgery, the patient remains alive without tumor recurrence.

[A Family with Peutz-Jeghers Syndrome Having Various Malignant Diseases].

We report a 27-year-old female who was diagnosed with adenocarcinoma of the uterine cervix associated with Peutz- Jeghers syndrome(PJS). She had undergone 5 surgeries for intestinal intussusception and had been diagnosed with PJS. She was referred to our hospital, complaining of watery vaginal discharge, and was diagnosed with adenocarcinoma of the uterine cervix. Following neoadjuvant chemotherapy, radical hysterectomy and small intestinal polypectomy by intraoperative endoscopy were performed. Among the third-degree relatives of her family, 10 had been diagnosed with PJS; of these 10, uterine cervical adenocarcinoma occurred in 3 relatives, pancreatic cancer in 2, cholangiocellular carcinoma in 1, and colon cancer in 1. Patients with PJS are at increased risk of developing malignant tumors in various organs. A recent review of the literature from Japan revealed that the cumulative cancer risk was estimated to be 83%by the age of 70 years, with especially high incidence rates of uterine cervical adenocarcinoma, colorectal cancer, and pancreas cancer. Surveillance for malignant neoplasms in patients with PJS is recommended, focusing on the sex and age of the patients.

Epithelial aPKC deficiency leads to stem cell loss preceding metaplasia in colorectal cancer initiation.

The early mechanisms of spontaneous tumor initiation that precede malignancy are largely unknown. We show that reduced aPKC levels correlate with stem cell loss and the induction of revival and metaplastic programs in serrated- and conventional-initiated premalignant lesions, which is perpetuated in colorectal cancers (CRCs). Acute inactivation of PKCλ/ι in vivo and in mouse organoids is sufficient to stimulate JNK in non-transformed intestinal epithelial cells (IECs), which promotes cell death and the rapid loss of the intestinal stem cells (ISCs), including those that are LGR5+. This is followed by the accumulation of revival stem cells (RSCs) at the bottom of the crypt and fetal-metaplastic cells (FMCs) at the top, creating two spatiotemporally distinct cell populations that depend on JNK-induced AP-1 and YAP. These cell lineage changes are maintained during cancer initiation and progression and determine the aggressive phenotype of human CRC, irrespective of their serrated or conventional origin.

Brg1 controls stemness and metastasis of pancreatic cancer through regulating hypoxia pathway.

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease. We previously reported that chromatin remodeler Brg1 is essential for acinar cell-derived PDAC formation in mice. However, the functional role of Brg1 in established PDAC and its metastasis remains unknown. Here, we investigated the importance of Brg1 for established PDAC by using a mouse model with a dual recombinase system. We discovered that Brg1 was a critical player for the cell survival and growth of spontaneously developed PDAC in mice. In addition, Brg1 was essential for metastasis of PDAC cells by inhibiting apoptosis in splenic injection and peritoneal dissemination models. Moreover, cancer stem-like property was compromised in PDAC cells by Brg1 ablation. Mechanistically, the hypoxia pathway was downregulated in Brg1-deleted mouse PDAC and BRG1-low human PDAC. Brg1 was essential for HIF-1α to bind to its target genes to augment the hypoxia pathway, which was important for PDAC cells to maintain their stem-like properties and to metastasize to the liver. Human PDAC cells with high BRG1 expression were more susceptible to BRG1 suppression. In conclusion, Brg1 plays a critical role for cell survival, stem-like property and metastasis of PDAC through the regulation of hypoxia pathway, and thus could be a novel therapeutic target for PDAC.