Elevated expression of RAB3B plays important roles in chemoresistance and metastatic potential of hepatoma cells.

BACKGROUND: Cancer stem cells (CSCs) are thought to play important roles in carcinogenesis, recurrence, metastasis, and therapy-resistance. We have successfully induced cancer stem-like sphere cells (CSLCs) which possess enhanced chemoresistance and metastatic potential. To enable the development of targeted therapy against CSLCs, we identified a gene responsible for this phenotype in CSLC. METHODS: Human hepatoma cell line SK-HEP-1 was used for CSLC induction with a unique sphere inducing medium, and HuH-7 cells were used as non-sphere forming cells in the same condition. RNA-sequencing was performed followed by validation with quantitative RT-PCR and western blotting. Knockdown experiments were done by using CRISPR-Cas9 genome-editing, and the rescue experiments were performed using the expressing plasmid vector. Chemoresistance and liver metastasis of the cells, was studied following the splenic injection of cells to severely immune deficient mice and evaluated using the MTS assay. Quantification of exosomes in the medium was done using ELISA. RESULTS: RAB3B was identified as an up-regulated gene in both CSLCs and prognostically poor hepatocellular carcinoma (HCC) by RNA-sequencing. RAB3B-KD cells showed altered CSLC phenotypes such as sphere formation, chemoresistance, and metastatic potentials, and those were rescued by RAB3B complementation. Increased exosome secretion was observed in CSLCs, and it was not observed in the RAB3B-KD cells. In addition, the RAB3B expression correlated with the expression of ABCG2, APOE, LEPR, LXN, and TSPAN13. CONCLUSION: The up regulation of RAB3B may play an important role in the chemoresistance and metastatic potential of CSLCs.

[Postoperative Management of Refractory Pleural Effusion in a Patient with Esophageal Cancer Accompanied by Cirrhosis].

This study reports a case of a 61-year-old man with a chief complaint of anemia. The patient was diagnosed with esophageal cancer(Stage Ⅰ). Preoperative examination revealed alcoholic liver cirrhosis(Child-Pugh A, liver damage B). After a period of abstinence to improve liver function, minimally invasive esophagectomy, retrosternal reconstruction with a gastric tube, and two-field lymph node dissection were performed. The thoracic duct was preserved during the operation. Post- surgery, the bill pleural effusion was increased. Drainage was initiated using thoracentesis with frosemide, spironolactone, and tolvaptan. On post-operating day(POD)35, the patient was discharged; however, right pleural effusion continued to increase. Therefore, cell-free and concentrated reinfusion therapy for right pleural effusion was performed on POD 56. After the treatment, the pleural effusion was well-controlled with 20 mg of frosemide. This case suggested that cell-free and concentrated pleural effusion reinfusion therapy contributed to the management of refractory pleural effusion in patients with esophageal cancer accompanied by cirrhosis.

[Recurrent Esophageal Cancer with Metastatic Lymph Node Penetrating in the Reconstructed Gastric Tube-A Case Report].

A 60-year-old man underwent thoracoscopic subtotal esophagectomy and posterior mediastinal gastric tube reconstruction after neoadjuvant chemotherapy. One year and 8 months postoperatively, recurrence was observed in the abdominal lymph nodes around the celiac artery and abdominal aorta. Chemoradiotherapy was initiated, followed by chemotherapy. Two months after the completion of chemoradiotherapy, the patient developed epigastric pain and anorexia because of the necrotic lymph node penetrating the gastric tube with cavity formation. Upper gastrointestinal endoscopy revealed a 25- mm-sized ulcer with central necrotic slough on the posterior wall of the stomach. Abdominal symptoms alleviated after conservative treatment with fasting and administration of antibiotics, and the inflammatory reaction improved. Oral nutritional supplements were started on hospitalization day 7, and abdominal symptoms or inflammatory reactions did not recur after resuming diet. The patient was discharged on hospitalization day 39 when the general condition stabilized. Subsequently, chemotherapy was restarted, and no regrowth of metastatic lesions was observed on endoscopy or CT examination 4 months later. Three years and 8 months after the recurrence, the recurrent disease has been controlled.

[Two Cases of Unresectable Gastric Cancer Where Bleeding Was Controlled by Radiation].

Case 1: The patient was a 74-year-old man with a performance status(PS)of 0. He was referred to our department for pyloric gastric cancer with multiple liver, lung, and lymph node metastases. We started chemotherapy after making the diagnosis of an unresectable gastric cancer. During chemotherapy, the hemoglobin level dropped due to bleeding from the tumor. We attempted endoscopic hemostasis, which was not successful; therefore, we attempted a palliative radiotherapy. The total dose was 30 Gy in 10 Fr and hemostasis was achieved on the 10th day from the start of the radiotherapy. There were no adverse events due to the radiation, and the chemotherapy could be restarted 5 days after the end of the radiotherapy. Case 2: The patient was a 78-year-old man with a PS of 2. He was referred to our department because of vomiting and anemia. As a result of a close inspection, we made the diagnosis of an unresectable gastric body cancer with para-aortic lymph node metastasis and peritoneal dissemination, for which chemotherapy was initiated. Anemia was observed at the first visit, and we started radiotherapy to stop the tumor bleeding. The total dose was 30 Gy in 10 Fr, and hemostasis was achieved on the 12th day. There were no adverse events during the radiotherapy, and chemotherapy could be continued. Palliative radiotherapy is an available method of hemostasis that is less invasive than surgery or transcatheter arterial embolization and can be expected to have a certain effect for gastric cancer bleeding, although it takes several days to obtain a therapeutic effect.

Metastatic ability and the epithelial-mesenchymal transition in induced cancer stem-like hepatoma cells.

Cancer stem cells (CSCs) are thought to play important roles in cancer malignancy. Previously, we successfully induced sphere cancer stem-like cells (CSLCs) from several cell lines and observed the property of chemoresistance. In the present study, we examined the metastatic potential of these induced CSLCs. Sphere cancer stem-like cells were induced from a human hepatoma cell line (SK-HEP-1) in a unique medium containing neural survival factor-1. Splenic injection of cells into immune-deficient mice was used to assess hematogenous liver metastasis. Transcriptomic strand-specific RNA-sequencing analysis, quantitative real-time PCR, and flow cytometry were carried out to examine the expression of epithelial-mesenchymal transition (EMT)-related genes. Splenic injection of CSLCs resulted in a significantly increased frequency of liver metastasis compared to parental cancer cells (P < .05). In CSLCs, a mesenchymal marker, Vimentin, and EMT-promoting transcription factors, Snail and Twist1, were upregulated compared to parental cells. Correspondingly, significant enrichment of the molecular signature of the EMT in CSLCs relative to parental cancer cells was shown (q < 0.01) by RNA-sequencing analysis. This analysis also revealed differential expression of CD44 isoforms between CSLCs and parental cancer cells. Increasing CD44 isoforms containing an extra exon were observed, and the standard CD44 isoform decreased in CSLCs compared to parental cells. Interestingly, another CD44 variant isoform encoding a short cytoplasmic tail was also upregulated in CSLCs (11.7-fold). Our induced CSLCs possess an increased liver metastatic potential in which promotion of the EMT and upregulation of CD44 variant isoforms, especially short-tail, were observed.

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.

BACKGROUND: In 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 METHODS: Between 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. RESULTS: Although 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. CONCLUSION: TE compared to OE is a less invasive procedure with lower surgical stress and less pulmonary complication for the treatment of esophageal squamous cell carcinoma.

[A Case of Esophageal Submucosal Tumor Undiagnosed Preoperatively and Treated with Thoracoscopic Enucleation].

An asymptomatic 35-year-old man visited our hospital because of an esophageal abnormality identified on a medical check-up. Gastrointestinal endoscopic examination revealed a 4 cm diameter submucosal tumor(SMT)in the upper esophagus. endoscopic ultrasound fine-needle aspiration biopsy(EUS-FNAB)was performed. Histopathological examination showed that it was strongly positive for a-SMA and partially positive for c-kit. An esophageal leiomyoma was suspected but esophageal gastrointestinal stromal tumor(GIST)could not be completely ruled out. After considering the patient's age and the location of the tumor, we performed thoracic enucleation of the esophageal SMT. Immunostaining findings showed that it was a-SMA positive and S-100 negative. Mast cells, but not tumor cells were partially stained with c-kit. The final pathological diagnosis was leiomyoma. The postoperative course was uneventful. We report this case together with a review of the literature.

[A Case of Ascending Colon Cancer with Extensive Abdominal Wall Abscess].

A 51-year-old woman was seen in our hospital because an ascending colon tumor with extensive abdominal wall abscess was detected on computed tomography(CT). On the same day, we performed open drainage and laparoscopic assisted ileocolostomy. Postoperative day 35, we performed right hemicolectomy with abdominal wall resection and closure of the colostomy as a radical surgery. After surgery, we started(negative pressure wound therapy: NPWT)to the surgical wound site; hence, the abdominal wall defect could be healed without a musculocutaneous flap. Laparoscopic assisted open drainage, a two-stage operation, and NPWT are useful in a case of colon cancer with abdominal wall abscess.

[A Case of Heterochronic Cervical Esophageal Cancer with a Subcutaneous Abscess Showing a Complete Response to Chemoradiation Therapy].

We report a case of heterochronic cervical esophageal cancer with a subcutaneous abscess successfully treated using chemoradiation. A 68-year-old man underwent esophagectomy for middle thoracic esophageal cancer 13 years ago. In April 2015, upper gastrointestinal endoscopy revealed advanced residual cervical esophageal cancer. Enhanced CT showed a massive tumor with a subcutaneous abscess, and the tumor had invaded the left internal jugular vein and the 8th cervical spine. We firstly performed abscess drainage and administered antibiotics. After the inflammation decreased, we started chemora- diation. Chemotherapy consisted of 70mg/m / 2 cisplatin(day 1)and 700 mg/m2 5-FU(days 1-5)combined with almost 60 Gy radiotherapy(1.8 Gy/day, 5 days/week, days 1-49). We administered cisplatin and 5-FU only once because renal dys- function occurred. Consequently, we changed the regimen to weekly 100mg/m2 paclitaxel administration(day 1). After 2 months, a clinical complete response(CR)was obtained and we stopped chemotherapy. Eight months after chemotherapy cessation, the patient shows no sign of recurrence. These results suggest that chemoradiation is an effective treatment for cervical esophageal cancer with a subcutaneous abscess.

[A case of metachronous liver metastasis from gastric cancer successfully treated with hepatectomy].

The use of hepatectomy for the treatment of liver metastasis from gastric cancer has been controversial. We report a case of metachronous liver metastasis from gastric cancer, which we successfully treated with hepatectomy. A 59-year-old man underwent laparoscopy-assisted total gastrectomy with D1 plus lymphadenectomy for gastric cancer. The histopathological findings revealed that the tumor was a well-differentiated tubular adenocarcinoma, T2(MP), N1(#1 2/3), M0, fStage II, according to the 14th edition of the Japanese Classification of Gastric Carcinoma. TS-1 was administered as adjuvant chemo- therapy for 1 year after the operation. About 5 years after the gastrectomy, a recurrent tumor was detected in S5/8-7 of the liver. Although chemotherapy with TS-1 plus Lentinan was administered, the liver tumor increased in size. Percutaneous transhepatic portal embolization was performed to improve liver function followed by resection of the right lobe of the liver. Paclitaxel plus doxifluridine (5'-DFUR) was administered for 6 months as adjuvant chemotherapy. No recurrence was observed for 17 months after hepatectomy.

Preventing Pneumonia in High-risk Patients After Esophageal Cancer Surgery: Mini-tracheostomy and Tazobactam/Piperacillin.

BACKGROUND/AIM: We evaluated the usefulness of prophylactic mini-tracheostomy (PMT) and perioperative administration of tazobactam/piperacillin (TAZ/PIPC) in high-risk patients after esophagectomy. PATIENTS AND METHODS: We retrospectively studied 89 consecutive high-risk patients who underwent esophagectomy for esophageal cancer between January 2013 and December 2021. We defined patients with two or more of the following factors as high risk: age ≥70 years, performance status ≥1, respiratory dysfunction, liver dysfunction, cardiac dysfunction, renal dysfunction, diabetes mellitus, albumin <3.5 g/dl, and Brinkman index >600. Standard management was administered to the first 50 patients (standard group). PMT and TAZ/PIPC were administered to the next 39 patients (combination group). Patient characteristics and short-term outcomes were compared before and after propensity-score matching. RESULTS: Before propensity-score matching, 24-hour urine creatinine clearance, retrosternal route, 3-field lymph node dissection, and open abdominal approach were more common, postoperative pneumonia (13% vs. 36%, p=0.045) and complications of grade ≥3b (2.6% vs. 22%, p=0.01) were less frequent, and the postoperative hospital stay was shorter (median: 23 vs. 28 days, p=0.022) in the combination group than in the standard group. In propensity-score matching, patient characteristics, except for 24-h creatinine clearance and reconstructive route, were matched for 23 paired patients. Postoperative pneumonia (8.7% vs. 39%, p=0.035) and complications of grade ≥3b (0% vs. 26%, p=0.022) were less frequent and postoperative hospital stay was shorter (median: 22 vs. 25 days, p=0.021) in the combination group than in the standard group. CONCLUSION: PMT with TAZ/PIPC can potentially prevent postoperative pneumonia in high-risk patients after esophagectomy.

Exosomal miR-141-3p Induces Gemcitabine Resistance in Biliary Tract Cancer Cells.

BACKGROUND/AIM: Gemcitabine (GEM)-based chemotherapy has been established as the core multimodal therapy for biliary tract cancer (BTC). However, the prognosis of BTC is unfavorable because of its resistance to GEM. Exosomes play important roles in the regulation of tumor progression and metastasis, immune dysregulation, and chemoresistance. This study investigated the effects of exosomes on GEM resistance in BTC. MATERIALS AND METHODS: The human intrahepatic cholangiocarcinoma cell line CC-LP-1, its GEM-resistant (GR) derivative cell line CC-LP-1-GR, and the human intrahepatic cholangiocarcinoma cell lines HuCCA-1 and HuCCT1, were used. GEM resistance was examined by measuring cell viability in the presence of GEM using an MTS assay. Exosomes were isolated using ultracentrifugation and quantified using ELISA. Comprehensive expression analysis was performed using RNA sequencing. The effects of microRNAs were examined by miRNA mimic transfection. RESULTS: The conditioned medium and exosomes derived from CC-LP-1-GR cells enhanced the GEM resistance of parental CC-LP-1 cells. In the presence of GEM, the p53 pathway was negatively enriched in CC-LP-1-GR and CC-LP-1 cells treated with exosomes from CC-LP-1-GR (rExo) compared to CC-LP-1 cells. The expression of miR-141-3p was higher in rExos than in CC-LP-1 cells. CC-LP-1 cells transfected with miR-141-3p mimic showed significantly (p<0.05) increased viability in the presence of GEM. CONCLUSION: A GEM-resistant human BTC cell line, CC-LP-1-GR, may acquire resistance to GEM by exosomes containing miR-141-3p.

Risk factors for infectious complications after gastrectomy in older patients.

The present study aimed to identify preoperative and perioperative risk factors for postoperative infectious complications in older patients with gastric cancer. The present retrospective study included 504 patients with gastric cancer aged >65 years who underwent radical gastrectomy. After determining the cutoff values for various perioperative factors in the receiver operating characteristic curve analysis, preoperative and perioperative risk factors for the development of infectious complications after gastrectomy were examined using logistic regression analysis. Of the 504 patients who underwent gastrectomy, 95 (18.8%) developed infectious complications of grade II-V based on the Clavien-Dindo classification. In an analysis restricted to preoperative factors, male sex, low prognostic nutritional index, high visceral fat area and total gastrectomy were independent risk factors for infectious complications after gastrectomy. Among all perioperative factors, a low prognostic nutritional index and long operative duration were identified as independent risk factors for infectious complications after gastrectomy. The patients were divided into five groups according to the number of positive preoperative risk factors for infectious complications, and the incidence of infectious complications differed among the five groups (0 factors, 6.7%; 1 factor, 10.4%; 2 factors, 18.9%; 3 factors, 27.8%; and 4 factors, 47.6%; P<0.001). Older patients with gastric cancer who have a number of preoperative risk factors require careful consideration of the indication for gastrectomy and a shorter operative time to reduce infectious complications.

Effects of Extended Fixation on Advanced Gastric Cancer HER2 Status Assessment Using IHC and FISH.

BACKGROUND/AIM: In gastric cancer, accurate determination of human epidermal growth factor receptor type 2 (HER2) status is crucial for treatment decision-making. However, the optimal formalin fixation time of gastric cancer specimens for HER2 status determination remains unestablished. Here, we investigated real-world data on formalin overfixation and its effect on HER2 status determination in gastric cancer. PATIENTS AND METHODS: We comprehensively analyzed HER2 testing results in 228 gastric cancer specimens, including those subjected to formalin overfixation. Subsequently, we divided 52 resected specimens of advanced gastric cancer into three groups and studied the effects of short-term (6-72 h) and long-term (1 and 2 weeks) fixation on HER2 status determination using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). RESULTS: A total of 21.5% (49/228) of the specimens were HER2-positive, whereas 78.5% (179/228) were negative. Among the HER2-negative specimens, no biopsies were overfixed, whereas 12.5% (9/72) of the surgical resection specimens were overfixed. The HER2 status of the 6-72-h group was 82.7% and 76.9% identical to that of the 1- and 2-week groups, when determined using IHC, and 73.1% and 36.5%, when determined using FISH, respectively. However, HER2 determination was not feasible in 26.9% and 63.5% of the specimens in the 1- and 2-week groups, respectively. CONCLUSION: Formalin overfixation may hinder the determination of HER2 status and should be avoided in gastric cancer sample preparation.

[Long-term survival of a case of juvenile colon cancer with multiple liver metastases successfully treated by multidisciplinary therapy].

A 35-year-old woman underwent hemicolectomy and RFA for ascending colon cancer with multiple liver metastases in February, 2005. She received postoperative hepaticarterial infusion chemotherapy with 5-FU, and systemic hemotherapy with UFT for 10 months after the operation. A local recurrence of the anastomosis was detected in March, 2006, and she underwent a resection for it. This was followed by 6 courses of adjuvant chemotherapy with modified FOLFOX6. Because multiple liver metastases and lymph node metastases were detected in March, 2007, she received RFA and 6 courses of adjuvant chemotherapy with modified FOLFOX6 again. Liver metastases disappeared but lymph node metastases still remained. Therefore, she received 4 courses of bevacizumab plus modified FOLFOX6. The metastatic lesions disappeared and were judged to be CR. Therefore, she was followed-up with the oral administration of UFT. Metastases of liver and lymph nodes of the mediastinum were detected in May, 2008, for which she received 4 courses of bevacizumab plus FOLFIRI2. Because the effects of the chemotherapy were judged to be CR, she continued with 4 courses of the same regimen. The regimen was discontinued due to diarrhea, and she therefore began to receive 4 courses of bevacizumab plus LV/5-FU regimens. CR has been maintained at present, over 7 years after the initial surgery.

[A case of pathologically by complete response in advanced sigmoid colon cancer with multiple metastases of lung and Liver, left hydronephrosis after chemotherapy including bevacizumab/FOLFOX6].

A 61-year-old complaining of anorexia and general fatigue was admitted to our hospital for further examination. She was diagnosed as advanced sigmoid colon cancer with multiple metastases of lung, liver, and left hydronephrosis. Since curative surgery was not deemed possible, we started chemotherapy with bevacizumab/FOLFOX6 (bi-weekly drip infusion). After the 6th course, colonoscopy revealed a significant tumor reduction and changes to the scar tissues. CT did not reveal a complete disappearance, but found some reductions in metastases of lung and liver. Sigmoidectomy and lymph node resection (D1) were performed. We did not disappeared any dissemination and the histological diagnosis revealed a complete disappearance of cancer cells in the main tumor. She was discharged 13 days after surgery, following chemotherapy which included bevacizumab and XELOX. The chemotherapy using bevacizumab/FOLFOX6 is a candidate for the standard treatment strategy for inoperable advanced colon cancer. Herein we report this rare case with a review of the literature.

[A case of advanced gastric cancer successfully treated with docetaxel and S-1 combined therapy].

A 46-year-old woman with lower abdominal distension was diagnosed as gastric cancer in our hospital. She had multiple metastases of lungs, lymph nodes, bilateral ovaries, and uterus. After she underwent sub-total gastrectomy, bilateral oophorectomy, and total hysterectomy, she received adjuvant chemotherapy followed by docetaxel and S-1. After 6 courses of chemotherapy, PET/CT revealed no recurrences (complete response), and she was therefore administered S-1 for only 6 months. She has remained without recurrence 15 months after the operation.

Risk factors for non-gastric-cancer-related death after gastrectomy in elderly patients.

Aim: To identify preoperative factors, especially other diseases that cause death, that are associated with the prognosis of gastrectomy in elderly patients with gastric cancer. Methods: This retrospective study included a total of 211 consecutive patients aged ≥75 years who underwent radical gastrectomy due to gastric cancer. Time-dependent receiver operating characteristic curve analysis was performed to determine the optimal cutoff values for various perioperative factors. Risk factors for the overall survival and death from other diseases were analyzed using the Cox proportional hazards model. Results: Among the all perioperative factors, sex, neutrophil-to-lymphocyte ratio, skeletal muscle mass index, and lymph node dissection in accordance with guidelines or not extracted as independent risk factors for death from other diseases. In an analysis restricted to the preoperative factors, sex, neutrophil-to-lymphocyte ratio, and skeletal muscle mass index of the patients were extracted as independent risk factors for death from other diseases and overall survival. We divided the patients into four groups according to the number of preoperative risk factors for death from other diseases and found that the 5-year non-gastric-cancer-related survival was different among the four groups (risk factor 0, 91.7%; risk factor 1, 83.3%; risk factor 2, 56.3%; risk factor 3, 27.2%; P < 0.001). Conclusion: Male sex, low skeletal muscle mass index, and high neutrophil-to-lymphocyte ratio are risk factors for non-gastric-cancer-related death and the overall survival of elderly patients undergoing gastrectomy. Cautious treatment strategies are needed for elderly gastric cancer patients with many risk factors.

Efficacy of intraoperative recurrent laryngeal neuromonitoring during surgery for esophageal cancer.

AIM: To evaluate the efficacy of intraoperative neuromonitoring in identifying recurrent laryngeal nerves and decreasing the incidence of nerve injury in minimally invasive esophagectomies for esophageal cancers. METHODS: A total of 167 minimally invasive esophagectomy patients were retrospectively reviewed. They were divided into intraoperative neuromonitoring (n = 84) and no intraoperative neuromonitoring (n = 83) groups, based on whether or not intraoperative neuromonitoring was used during surgery. We compared short-term surgical outcomes and incidence of recurrent laryngeal nerve palsy between the two groups before and after propensity score matching. The association between the loss of signal and recurrent laryngeal nerve palsy was also evaluated. RESULTS: The incidence of recurrent laryngeal nerve palsy (grade 2 and higher) was lower in the intraoperative neuromonitoring group than in the no intraoperative neuromonitoring group (6.0% vs 21.2%, P = 0.02). The rate of recurrent laryngeal nerve palsy recovery within 6 months was also significantly higher in the intraoperative neuromonitoring group (87.5% vs 20.0%, P < 0.01). The positive and negative predictive values of intraoperative neuromonitoring for recurrent laryngeal nerve palsy were 60% (9/15) and 86.9% (60/69), respectively. The duration from paralysis to recovery was shorter in recurrent laryngeal nerve palsy cases with negative loss of signal results than in cases with positive loss of signal results (median: 43 days vs 95 days). CONCLUSION: Intraoperative neuromonitoring is useful in identifying recurrent laryngeal nerves and may aid in reducing the incidence of recurrent laryngeal nerve injury during esophageal surgery.

Pancreatic Cancer Stem-Like Cells With High Calreticulin Expression Associated With Immune Surveillance.

OBJECTIVE: Pancreatic cancer stem-like cells (P-CSLCs) are thought to be associated with poor prognosis. Previously, we used proteomic analysis to identify a chaperone pro-phagocytic protein calreticulin (CALR) as a P-CSLC-specific protein. This study aimed to investigate the association between CALR and P-CSLC. METHODS: PANC-1-Lm cells were obtained as P-CSLCs from a human pancreatic cancer cell line, PANC-1, using a sphere induction medium followed by long-term cultivation on laminin. To examine the cancer stem cell properties, subcutaneous injection of the cells into immune-deficient mice and sphere formation assay were performed. Cell surface expression analysis was performed using flow cytometry. RESULTS: PANC-1-Lm showed an increased proportion of cell surface CALR-positive and side-population fractions compared with parental cells. PANC-1-Lm cells also had higher frequency of xenograft tumor growth and sphere formation than PANC-1 cells. Moreover, sorted CALRhigh cells from PANC-1-Lm had the highest sphere formation frequency among tested cells. Interestingly, the number of programmed death-ligand 1-positive cells among CALRhigh cells was increased as well, whereas that of human leukocyte antigen class I-positive cells decreased. CONCLUSION: In addition to the cancer stem cell properties, the P-CSLC, which showed elevated CALR expression on the cell surface, might be associated with evasion of immune surveillance.