Prognostic Value of Systemic Inflammatory Response in Lymph Node-Negative Colorectal Cancer.

BACKGROUND: The aim of this study was to investigate the prognostic value of systematic inflammatory response in patients with lymph node-negative colorectal cancer. METHODS: We retrospectively investigated 245 patients with lymph node-negative colorectal cancer who underwent curative resection and evaluated the prognostic impact of systematic inflammatory response, which was represented by neutrophil-to-lymphocyte ratio (NLR), prognostic nutritional index (PNI), and C-reactive protein-to-albumin ratio (CAR). Then, the prognostic significance of the systematic inflammatory response on survival was analyzed using the Kaplan-Meier method in patients selected by propensity score matching (PSM) analysis. RESULTS: In the multivariate analysis, CAR ≥ .081 (P = .004) was independent predictors of disease-free survival, while American Society of Anesthesiologists physical status ≥3 (P = .049) and CAR ≥ .081 (P < .001) were independent predictors of overall survival. By PSM analysis, PSM-high-CAR was significantly associated with worse disease-free survival (P = .043) and overall survival (P = .041) in patients with lymph node-negative colorectal cancer. CONCLUSIONS: C-reactive protein-to-albumin ratio may be a significant indicator of poor long-term outcomes in patients with lymph node-negative colorectal cancer.

Cholinesterase as a predictor of skeletal muscle loss after gastrectomy for gastric cancer.

BACKGROUND: Cholinesterase is a classical nutritional and inflammatory marker. The aim of the present study was to evaluate the value of cholinesterase as a predictive marker for postoperative skeletal muscle loss after gastrectomy for gastric cancer. METHODS: The study comprised 68 patients who had undergone gastrectomy for gastric cancer. Skeletal muscle mass was evaluated using skeletal mass index, and major skeletal muscle loss was defined as less than or equal to the median change rate (1-year postoperative/preoperative) of skeletal mass index in all patients. We explored the relationship between postoperative major skeletal muscle loss and disease-free survival and overall survival. Then we investigated the relationship between change rate of skeletal muscle index and serum cholinesterase levels after gastrectomy. RESULTS: The median value of change rate of skeletal mass index was 0.93. Postoperative major skeletal muscle loss was significantly associated with disease-free survival after gastrectomy (P = 0.003). Although major skeletal muscle loss had worse overall survival, it was not significant (P = 0.058). The change rate of skeletal mass index and cholinesterase had a stronger positive correlation compared with other nutritional indices according to Spearman's rank correlation coefficient (r = 0.438, P ≤ 0.001). CONCLUSION: Evaluation of serum cholinesterase levels may be valuable for predicting postoperative skeletal muscle loss after gastrectomy, suggesting the importance of cholinesterase in postoperative nutritional management of patients with gastric cancer.

Cachexia Index in Patients with Gastrointestinal Cancer: A Systematic Review and Meta-Analysis.

PURPOSE: The cachexia index is a novel biomarker of cancer cachexia. This systematic review and meta-analysis aimed to evaluate the prognostic impact of cachexia index on prognosis after surgery for gastrointestinal cancer. METHODS: In August 2023, we systematically searched PubMed, the Cochrane Library, and Ovid for relevant studies on the oncological outcome after gastrointestinal cancer surgery and analyzed the findings from these studies for meta-analysis. RESULTS: Our systematic and meta-analysis review identified eight studies involving 1876 patients. The number of patients with low cachexia index accounted for 813 patients (43.3%). We found that low cachexia index was associated with worse overall survival (pooled HR, 2.30; 95% CI, 1.85-2.87; z = 7.49; P < 0.001) and disease/relapse/progression-free survival (pooled HR, 1.77; 95% CI, 1.45-2.18; z = 5.50; P < 0.001). CONCLUSION: Our meta-analysis showed that cachexia index was associated with oncological outcome after gastrointestinal cancer surgery. However, the limitations of this meta-analysis should be taken into consideration when interpreting the results.

Association of Cholinesterase With Postoperative Pneumonia After Gastrectomy for Gastric Cancer.

INTRODUCTION: Cholinesterase is a classical marker that reflects nutritional and inflammatory status. The aim of the present study was to evaluate the association between serum cholinesterase levels and postoperative infectious complications in patients undergoing gastrectomy for gastric cancer. MATERIALS AND METHODS: This retrospective study comprised 108 patients who underwent gastrectomy for gastric cancer. We comprehensively investigated the association between clinicopathological variables and postoperative infectious complications after gastrectomy. Then patients were divided into the cholinesterase-high and -low groups to analyze their clinicopathological variables. Finally, we analyzed the types of infectious complications that were most associated with preoperative serum cholinesterase levels. RESULTS: Twenty-six patients (24%) developed postoperative infectious complications. Multivariate analysis revealed that serum cholinesterase levels (P = 0.026) and N stage (P = 0.009) were independent risk factors for postoperative infectious complications. In particular, the incidence of pneumonia (P = 0.001) was significantly higher in the cholinesterase-low group. Age (P = 0.023), cerebrovascular comorbidities (P = 0.006), serum cholinesterase levels (P = 0.013), and total gastrectomy (P = 0.017) were identified as independent risk factors for postoperative pneumonia. CONCLUSIONS: Preoperative serum cholinesterase levels were associated with postoperative pneumonia after gastrectomy for gastric cancer, suggesting the importance of preoperative nutritional assessment in gastric cancer surgery.

Indocyanine Green Fluorescent Lymphography During Open Inguinal Hernia Repair: Relationship Between Lymphatic Vessel Injury and Postoperative Hydrocele.

BACKGROUND: This prospective case series analyzed patients who underwent indocyanine green (ICG) fluorescent lymphography during open inguinal hernia repair. The aim of this study was to investigate the association between ICG leakage and postoperative hydroceles in patients who underwent inguinal hernia repair. MATERIALS AND METHODS: Data were analyzed from 40 patients who underwent primary open hernia repair between October 2020 and June 2021 (44 cases in total). Hydroceles were categorized into two types: symptomatic and "ultrasonic" (detected only by ultrasound imaging). RESULTS: In the univariate analysis, hernia type (p = 0.044) and ICG leakage (p = 0.007) were independent risk factors for postoperative ultrasonic hydroceles. Additionally, mesh type (p = 0.043) and ICG leakage (p = 0.025) were independent risk factors for postoperative symptomatic hydroceles. In the multivariate analysis, ICG leakage (p = 0.034) was an independent risk factor for postoperative ultrasonic hydroceles. CONCLUSIONS: ICG leakage after inguinal hernia repair was independently associated with postoperative ultrasonic and symptomatic hydroceles. These findings suggest a relationship between lymphatic vessel injury and the incidence of postoperative hydroceles.

Short-term outcomes of colorectal cancer surgery in patients with dialysis: a systematic review and meta-analysis.

PURPOSE: This systematic review and meta-analysis aimed to evaluate the effect of dialysis-dependent chronic kidney disease (CKD) on postoperative complications in colorectal cancer surgery. METHODS: In April 2023, we systematically searched PubMed, the Cochrane library, and Ovid for relevant studies on short-term outcomes of colorectal cancer surgery in patients with dialysis and analyzed the findings from these studies for meta-analysis. RESULTS: Our systematic and meta-analysis review identified seven studies involving 50713 patients. We showed that the dialysis group had higher rates of mortality (OR = 4.12, 95%CI: 2.75-6.20, P < 0.001), cardiac complications (OR = 2.45, 95%CI: 1.88-3.21, P < 0.001), and pneumonia (OR = 2.68, 95%CI: 1.83-3.93, P < 0.001). On the other hand, there were no differences in superficial/deep surgical site infection (SSI) (odds ratio [OR] = 1.17, 95%CI: 0.90-1.53, P = 0.230) and organ/space SSI (OR = 1.35, 95%CI: 1.00-1.82, P = 0.053) between the dialysis group and non-dialysis group. CONCLUSION: Our meta-analysis showed that dialysis-dependent CKD was associated with higher rates of mortality, cardiac complications, and pneumonia after colorectal cancer surgery. However, the limitations of this meta-analysis should be taken into consideration when interpreting the results.

The influence of serum cholinesterase levels and sarcopenia on postoperative infectious complications in colorectal cancer surgery.

PURPOSE: Cholinesterase is a nutritional marker associated with sarcopenia. The present study evaluated the relationship between cholinesterase and postoperative infectious complications in patients undergoing colorectal resection for colorectal cancer. METHODS: The study involved 231 patients who had undergone colorectal resection for colorectal cancer. We retrospectively investigated the relationship between preoperative serum cholinesterase levels and postoperative infectious complications. Univariate and multivariate analyses were performed to identify independent risk factors for postoperative infectious complications. We then performed stratified analyses to assess the interaction between cholinesterase and clinical variables to predict postoperative infectious complications. RESULTS: In the multivariate analysis, the body mass index (P = 0.010), serum cholinesterase levels (P = 0.005), sarcopenia (P = 0.003) and blood loss (P < 0.001) were independent risk factors for postoperative infectious complications. In stratified analyses, the association between serum cholinesterase levels and postoperative infectious complications differed by the sarcopenia status (Pinteraction = 0.006). CONCLUSION: Preoperative serum cholinesterase levels may be useful for predicting postoperative infectious complications in colorectal cancer surgery. The association differs by the sarcopenia status, suggesting a potential interaction between nutritional markers and sarcopenia.

Significance of osteopenia in elderly patients undergoing emergency gastrointestinal surgery.

Aim: Frailty assessment in elderly patients is crucial to predict the postoperative course, considering that frailty is highly associated with postoperative complications and mortality. The aim of this study was to evaluate the value of osteopenia as a risk factor for severe postoperative complications in elderly patients who underwent emergency gastrointestinal surgery. Methods: This study comprised 103 elderly patients who underwent emergency gastrointestinal surgery. Osteopenia was diagnosed by measuring bone mineral density, which was calculated as the average pixel density in the midvertebral core at the 11th thoracic vertebra on the preoperative plain computed tomography image. We retrospectively investigated the relationship between preoperative osteopenia and severe postoperative complications (Clavien-Dindo classification ≥III). Univariate and multivariate analyses were performed to evaluate the risk factors for severe postoperative complications. Results: Twenty-three patients (22.3%) developed severe postoperative complications. The optimal cutoff value of bone mineral density for severe postoperative complications was 119.5 Hounsfield unit (HU) and 39 patients (37.9%) were diagnosed with osteopenia. The univariate analysis revealed that the American Society of Anesthesiologists Physical Status of ≥3 (P = .0084), hemoglobin levels (P = .0026), albumin levels (P < .001), sarcopenia (P = .015), and osteopenia (P < .001) were significantly associated with severe postoperative complications. The multivariate analysis showed that osteopenia (P = .014) was an independent risk factor for severe postoperative complications. Conclusion: Osteopenia may be a risk factor for severe postoperative complications in elderly patients after emergency gastrointestinal surgery.

Usefulness of percutaneous transesophageal gastrotubing for gastric outlet obstruction secondary to duodenal ulcer, a case report.

Severe duodenal ulcer stenosis requires continuous decompression, which makes oral ingestion difficult, yet poor nutritional status before surgery increases the risk postoperative complications. Double percutaneous transesophageal gastrotubing (dPTEG) is a new treatment that provides both decompression and enteral nutrition. We report a case of duodenal ulcer scar stenosis in which dPTEG was used for preoperative management. A man in his 40s visited our hospital with vomiting as a chief complaint. CT scan showed duodenal ulcer stenosis. As the existence of malignant disease could not be ruled out, surgery was planned. Before surgery, dPTEG was inserted to achieve decompression and nutritional management. The patient's gastric distension and nutritional status improved significantly, and laparoscopic distal gastrectomy was performed 22 days after the insertion. dPTEG may be an effective management method for patients with pyloric stenosis due to duodenal ulcer.

Nivolumab in combination with radiotherapy for metastatic esophageal neuroendocrine carcinoma after esophagectomy: a case report.

BACKGROUND: Metastatic neuroendocrine carcinoma has an extremely poor prognosis, and no effective second-line treatment is available. Herein, we describe a case of multiple metastases after primary resection of esophageal neuroendocrine carcinoma successfully treated with nivolumab plus radiotherapy in a short time. CASE PRESENTATION: A man in his 70s presented to our hospital after an abnormality was detected on an upper gastrointestinal series. Upper gastrointestinal endoscopy revealed a type 2 tumor spanning the endothelial cell junction to the abdominal esophagus. Histopathological examination of the biopsy confirmed a diagnosis of esophageal neuroendocrine carcinoma. The patient had no distant metastases. Thoracoscopic esophagectomy with three-field lymph node dissection was performed. Histopathological examination confirmed a diagnosis of esophageal neuroendocrine carcinoma with features of adenoid cystic-like carcinoma and squamoid pattern (pT2 [MP], INF a, ly1, v1 [EVG], pIM0, pDM0, pRM0, pN1 [1/28], M0; Stage II), which was positive for synaptophysin. The postoperative course was good, with no complications. The patient was treated with 100 mg of irinotecan and 100 mg of cisplatin, administered every 4 weeks, as postoperative adjuvant chemotherapy. Grade 3 loss of appetite was observed, and adjuvant chemotherapy was discontinued after four cycles of first-line treatment. A positron emission tomography-computed tomography scan 3 years after surgery showed abnormal uptake in the subaortic, left hilar, and left axillary lymph nodes, and in a mass in the right lung apex. The patient was diagnosed with metastatic esophageal neuroendocrine carcinoma postoperatively. First-line treatment could not be repeated due to toxicity from the initial treatment. Nivolumab (240 mg every 2 weeks) was administered as second-line treatment, and radiotherapy was started (56 Gy delivered in 28 fractions to the local [subaortic and hilar] lymph nodes). After 10 cycles of nivolumab in combination with radiotherapy (56 Gy), a positron emission tomography-computed tomography scan showed disappearance of all lesions. A complete response was achieved. Maintenance therapy (240 mg of nivolumab) was continued. No recurrence has been observed for 42 months. CONCLUSIONS: We experienced a case in which nivolumab in combination with radiotherapy was effective for metastatic esophageal neuroendocrine carcinoma after primary resection.

Perineal stapled prolapse resection in combination with Thiersch operation for relapsed rectal prolapse: a case report.

BACKGROUND: Treatment options for complete rectal prolapse include over 100 procedures. In previous reports, operative rectal prolapse repair, regardless of the technique by perineal approach, was associated with high recurrence rates. However, there is no consensus on the optimal surgical procedure for relapsed rectal prolapse. CASE PRESENTATION: A 97-year-old woman was admitted to our hospital with a chief complaint of complete rectal prolapse measuring > 5 cm. The patient had a history of laparoscopic anterior suture rectopexy without sigmoid resection under general anesthesia for complete rectal prolapse one year prior. The patient's postoperative course was uneventful. However, her dementia worsened (Hasegawa's dementia scale: 5/30 points) after the first operation. Further, moderate-to-severe aortic valve stenosis was first diagnosed with heart failure 6 months after the operation. Nine months after the initial surgery, she experienced a recurrence of complete rectal prolapse measuring approximately 5 cm. Considering the coexistence of advanced age, severe dementia, and aortic valve stenosis, surgery under general anesthesia was not indicated. Perineal stapled prolapse resection in combination with the t operation was planned because of its minimal invasiveness and shortened hospital stay. The procedure was performed by a team of two surgeons in the jack knife position, under spinal anesthesia. The prolapse was cut along the long-axis direction with three linear staplers and resected along the short-axis direction with four linear staplers. The cross-section of the linear stapler was reinforced with 3-0 Vicryl sutures. After rectal resection, the Thiersch operation using 1-0 nylon thread 1 cm away from the anal verge was additionally performed. The operative time was 24 min, and intraoperative blood loss was 1 mL. The postoperative course was uneventful. Three months after the operation, no recurrence was observed, and defecation function was good with improvements of Wexner score. CONCLUSIONS: Perineal stapled prolapse resection in combination with the Thiersch operation could be a useful option for patients with relapsed rectal prolapse and with poor general condition, who are not indicated for other surgical procedures.

Minimally invasive colostomy with endoscopy as a novel technique for creation of a trephine stoma.

The conventional approach of trephine stoma creation is associated with various limitations, including poor elevation of the sigmoid colon, misidentification of the target organs, and poor visualization of the operative field, which may require conversion to an open approach. Our study aimed to evaluate the safety, feasibility, and complications of minimally invasive colostomy with endoscopy (MICE), a new technique for trephine stoma creation. This retrospective cohort study included 14 patients. Patients diagnosed with obstructive rectal cancer or bladder and rectal disorders due to spinal cord injury or bone metastasis requiring sigmoid loop colostomy were eligible for the procedure. MICE was performed using a combination of endoscopic and fluoroscopic procedures. The primary endpoint was the technical success of MICE. Technical success using MICE was achieved in all 14 cases. The mean total operative time was 52.6 (range 32-107) min, and mean blood loss was 18.9 (range 1-50) mL. There was no incidence of conversion to open surgery. Postoperative complications included peristomal abscess formation and ischemic colitis in each case. MICE may be useful as a minimally invasive approach for trephine stoma creation that overcomes the problems of a conventional approach in high-risk patients.

Indocyanine green fluorescence-guided laparoscopic colorectal cancer surgery with prophylactic retrograde transileal conduit ureteral catheter placement after previous total cystectomy: a case report.

BACKGROUND: Iatrogenic ureteral injury (UI) is a potentially serious complication of colorectal cancer surgery. Performing perioperative placement of ureteral stents or intraoperative fluorescence navigation surgery for the ureter using indocyanine green (ICG) has been employed as a method of preventing UI. However, transileal conduit stent placement has been considered challenging because it is difficult to identify the ureteral orifice due to the anatomical changes caused by a previous surgery. We report a case in which laparoscopic colectomy was safely performed using a combination of prophylactic transileal conduit ureteral catheter placement and intraoperative ICG fluorescence navigation surgery. CASE PRESENTATION: A 75-year-old man presented to our hospital complaining of vomiting and abdominal distension. He had a history of open total cystectomy and ileal conduit urinary diversion 11 years prior to admission. Computed tomography confirmed colon dilation with fecal impaction from the ascending colon to the sigmoid colon and wall thickening in the sigmoid colon. Colonoscopy during the transanal ileus tube insertion revealed a Borrmann type II tumor with circumferential stenosis 10 cm distal to the junction between the descending colon and the sigmoid colon. The patient was diagnosed with colorectal ileus due to obstructive sigmoid colon cancer and underwent transanal ileus tube insertion. Severe intra-abdominal adhesions were expected due to the previous total cystectomy, and the left ureter was near the sigmoid colon tumor; therefore, prophylactic retrograde transileal conduit ureteral catheter placement was performed one day before the elective surgery. During the operation, 20 ml (5.0 × 10-2 mg/ml) ICG was administered from the transileal conduit ureteral catheter, and ICG fluorescence of the ureter was observed in the retroperitoneum. Laparoscopic Hartmann's operation was successfully performed, confirming ureter fluorescence. The operation time was 231 min, with 5 mL of intraoperative bleeding. The ureteral catheter was removed 3 days after the operation. The patient's postoperative course was good with no complications, and he was discharged on postoperative day 7. CONCLUSIONS: Prophylactic transileal conduit ureteral catheter placement and ICG fluorescence navigation surgery were effective in performing laparoscopic colorectal surgery with severe adhesions after urinary diversion.

Laparoscopic resection of a metachronous secondary lymph node metastasis in the mesentery of the ileum after surgery for sigmoid colon cancer with ileum invasion: a case report.

BACKGROUND: Extended excision of the permeation organ neighborhood is often performed in locally invasive colon cancer, and it is reported to have a survival benefit. In addition, some cases of secondary lymph node metastases in a permeation organ were reported. However, they are reports of synchronous secondary lymph node metastases, not metachronous secondary lymph node metastases. To the best of our knowledge, there are no cases of metachronous secondary lymph node metastases after the resection of a primary colorectal cancer in PubMed. CASE PRESENTATION: The case was a 67-year-old man who underwent colonoscopy because of weight loss. Sigmoid colon cancer with all circumference-related stenosis was found by examination, and the patient was transferred to our hospital for the purpose of scrutiny and treatment. The small intestine ileus caused by the invasion of sigmoid colon cancer developed after the transfer. Laparoscopic high anterior resection and extended excision of small intestine segmental resection was performed after the intestinal tract decompression with a nasal ileus tube. Histopathological analysis revealed a pathological diagnosis of pT4b (ileal submucosal invasion) N0 (0/11) M0 f Stage II, tub2, ly1, v2, PN0. Although adjuvant chemotherapy with capecitabine after the operation was planned for half a year, treatment was suspended in the first course by the patient's self-judgment. No recurrence was observed for a year after the operation, but metastasis recurrence in the para-aortic lymph node was found by a computed tomography (CT) one and a half years after the operation. 18 F-fluorodeoxyglucose (FDG) positron emission tomography revealed that FDG was accumulated only in the para-aortic lymph node. Laparoscopic metastasis lymphadenectomy was performed due to the diagnosis of metachronous metastasis to the para-aortic lymph node alone. Intraoperative findings revealed that lymph node metastasis occurred in the mesentery of the ileum. No adjuvant treatment was done after the secondary operation, and he is still alive with no recurrence 1 year and 9 months after the operation. CONCLUSIONS: We report a rare case of a laparoscopic resection of a metachronous secondary lymph node metastasis in the mesentery of the ileum after surgery for sigmoid colon cancer with ileum invasion.

Laparoscopic resection of a neuroendocrine tumor that almost fully replaced tailgut cysts: a case report.

BACKGROUND: Neuroendocrine tumors (NETs) originate from neuroendocrine cells, which are found throughout the body. NETs occur principally in the gastrointestinal tract (approximately 65%) and bronchopulmonary tract (approximately 25%) but rarely occur in the presacral space. Aside from primary and metastatic lesions, there have been reports of NETs occurring in the presacral space arising from tailgut cysts, teratomas, and imperforate anus. We herein report a rare case of laparoscopic resection of a NET in the presacral space, which almost fully replaced tailgut cysts. CASE PRESENTATION: A 68-year-old woman was referred to our hospital for surgery of a right inguinal hernia, but preoperative computed tomography revealed an asymptomatic 43-mm mass in the presacral space. Magnetic resonance imaging showed a multilocular solid mass with clear boundaries and a slightly high signal intensity on T1- and T2-weighted images. Positron emission tomography showed 18F-fluorodeoxyglucose uptake. Thus, we suspected a malignant tumor and performed laparoscopic resection to obtain a definitive diagnosis. Macroscopically, the tumor was 43 mm in size with clear boundaries, and the cut surface was a gray-white solid component. Histopathological findings revealed that the tumor was composed of relatively uniform cells with fine chromatin, with round to oval nuclei arranged in solid, trabecular, or rosette-like growth patterns. Small cysts lined with stratified squamous epithelium and columnar epithelium were observed along with solid components of the tumor, which is a feature of tailgut cysts. Therefore, the final diagnosis was NET Grade 1 arising from tailgut cysts. No recurrence was observed within 1 year after surgery. CONCLUSIONS: We performed en bloc laparoscopic resection of a NET arising from tailgut cysts in the presacral space without injury. In cases of a solid lesion in the presacral space, not only the primary disease but also the pathological condition with tissue transformation and replacement should be considered, as in this case.

The Genetic Basis of Scale-Loss Phenotype in the Rapid Radiation of Takifugu Fishes.

Rapid radiation associated with phenotypic divergence and convergence provides an opportunity to study the genetic mechanisms of evolution. Here we investigate the genus Takifugu that has undergone explosive radiation relatively recently and contains a subset of closely-related species with a scale-loss phenotype. By using observations during development and genetic mapping approaches, we show that the scale-loss phenotype of two Takifugu species, T. pardalis Temminck & Schlegel and T. snyderi Abe, is largely controlled by an overlapping genomic segment (QTL). A search for candidate genes underlying the scale-loss phenotype revealed that the QTL region contains no known genes responsible for the evolution of scale-loss phenotype in other fishes. These results suggest that the genes used for the scale-loss phenotypes in the two Takifugu are likely the same, but the genes used for the similar phenotype in Takifugu and distantly related fishes are not the same. Meanwhile, Fgfrl1, a gene predicted to function in a pathway known to regulate bone/scale development was identified in the QTL region. Since Fgfr1a1, another memebr of the Fgf signaling pathway, has been implicated in scale loss/scale shape in fish distantly related to Takifugu, our results suggest that the convergence of the scale-loss phenotype may be constrained by signaling modules with conserved roles in scale development.

Construction of a radiation hybrid panel and the first yellowtail (Seriola quinqueradiata) radiation hybrid map using a nanofluidic dynamic array.

BACKGROUND: Yellowtail (Seriola quinqueradiata) are an economically important species in Japan. However, there are currently no methods for captive breeding and early rearing for yellowtail. Thus, the commercial cultivation of this species is reliant upon the capture of wild immature fish. Given this, there is a need to develop captive breeding techniques to reduce pressure on wild stocks and facilitate the sustainable development of yellowtail aquaculture. We constructed a whole genome radiation hybrid (RH) panel for yellowtail gene mapping and developed a framework physical map using a nanofluidic dynamic array to use SNPs (single nucleotide polymorphisms) in ESTs (expressed sequence tags) for the DNA-assisted breeding of yellowtail. RESULTS: Clonal RH cell lines were obtained after ionizing radiation; specifically, 78, 64, 129, 55, 42, and 53 clones were isolated after treatment with 3,000, 4,000, 5,000, 6,000, 8,000, or 10,000 rads, respectively. A total of 421 hybrid cell lines were obtained by fusion with mouse B78 cells. Ninety-four microsatellite markers used in the genetic linkage map were genotyped using the 421 hybrid cell lines. Based upon marker retention and genome coverage, we selected 93 hybrid cell lines to form an RH panel. Importantly, we performed the first genotyping of yellowtail markers in an RH panel using a nanofluidic dynamic array (Fluidigm, CA, USA). Then, 580 markers containing ESTs and SNPs were mapped in the first yellowtail RH map. CONCLUSIONS: We successfully developed a yellowtail RH panel to facilitate the localization of markers. Using this, a framework RH map was constructed with 580 markers. This high-density physical map will serve as a useful tool for the identification of genes related to important breeding traits using genetic structural information, such as conserved synteny. Moreover, in a comparison of 30 sequences in the RH group 1 (SQ1), yellowtail appeared to be evolutionarily closer to medaka and the green-spotted pufferfish than to zebrafish. We suggest that synteny analysis may be potentially useful as a tool to investigate chromosomal evolution by comparison with model fish.