Outcomes after distal pancreatectomy with or without splenectomy for intraductal papillary mucinous neoplasm: international multicentre cohort study.

BACKGROUND: International guidelines on intraductal papillary mucinous neoplasm (IPMN) recommend a formal oncological resection including splenectomy when distal pancreatectomy is indicated. This study aimed to compare oncological and surgical outcomes after distal pancreatectomy with or without splenectomy in patients with presumed IPMN. METHODS: An international, retrospective cohort study was undertaken in 14 high-volume centres from 7 countries including consecutive patients after distal pancreatectomy for IPMN (2005-2019). Patients were divided into spleen-preserving distal pancreatectomy (SPDP) and distal pancreatectomy with splenectomy (DPS). The primary outcome was lymph node metastasis (LNM). Secondary outcomes were overall survival, duration of operation, blood loss, and secondary splenectomy. RESULTS: Overall, 700 patients were included after distal pancreatectomy for IPMN; 123 underwent SPDP (17.6%) and 577 DPS (82.4%). The rate of malignancy was 29.6% (137 patients) and the overall rate of LNM 6.7% (47 patients). Patients with preoperative suspicion of malignancy had a LNM rate of 17.2% (23 of 134) versus 4.3% (23 of 539) among patients without suspected malignancy (P < 0.001). Overall, SPDP was associated with a shorter operating time (median 180 versus 226 min; P = 0.001), less blood loss (100 versus 336 ml; P = 0.001), and shorter hospital stay (5 versus 8 days; P < 0.001). No significant difference in overall survival was observed between SPDP and DPS for IPMN after correction for prognostic factors (HR 0.50, 95% c.i. 0.22 to 1.18; P = 0.504). CONCLUSION: This international cohort study found LNM in 6.7% of patients undergoing distal pancreatectomy for IPMN. In patients without preoperative suspicion of malignancy, SPDP seemed oncologically safe and was associated with improved short-term outcomes compared with DPS.

Neighboring macrophage-induced alteration in the phenotype of colorectal cancer cells in the tumor budding area.

BACKGROUND: A higher number of tumor buds in the invasive front of colorectal cancer (CRC) specimens has been shown to contribute to a poor prognosis in CRC patients. Because macrophages (Mφs) have been demonstrated to alter the phenotype of cancer cells, we hypothesized that the phenotype of CRC cells in the tumor budding (TB) area might be changed by the interaction between CRC cells and Mφs. METHODS: We assessed the expression of topoisomerase 1 in CRC cells to estimate the acquisition of chemoresistance in CRC. To demonstrate the tumor-stromal interaction between CRC cells and Mφs, we assessed two histological findings, the number of Mφs per single CRC cell and the proximity between CRC cells and Mφs by histological spatial analysis using HALO software. RESULTS: The expression levels of topoisomerase 1 in CRC cells were decreased in deeper areas, especially in the TB area, compared to the surface area. Our histological spatial analysis revealed that 2.6 Mφs located within 60 µm of a single CRC cell were required to alter the phenotype of the CRC cell. Double-immunofluorescence staining revealed that higher Mφs were positive for interleukin-6 (IL-6) in the TB area and that AE1/AE3-positive CRC cells were also positive for phospho-STAT3 (pSTAT3) in the TB area; thus, the IL-6 receptor (IL-6R)/STAT3 signaling pathway in CRC cells was upregulated by IL-6 derived from neighboring Mφs. CONCLUSION: IL-6 secreted from the neighboring Mφs would alter the phenotype of CRC cells via IL-6R/STAT3 signaling pathway.

Serine/Threonine Kinase 11 Plays a Canonical Role in Malignant Progression of KRAS -Mutant and GNAS -Wild-Type Intraductal Papillary Mucinous Neoplasms of the Pancreas.

OBJECTIVE: We aimed to elucidate the clinicopathobiological significance of Serine/Threonine Kinase 11 (STK11) in pancreatic intraductal papillary mucinous neoplasms (IPMNs). BACKGROUND: STK11 is a tumor suppressor involved in certain IPMNs; however, its significance is not well known. METHODS: In 184 IPMNs without Peutz-Jeghers syndrome, we analyzed expression of STK11 and phosphorylated-AMPKa in all cases, and p16, p53, SMAD4, and ß-catenin in 140 cases by immunohistochemistry; and we analyzed mutations in 37 genes, including whole coding exons of STK11, CDKN2A, TP53, and SMAD4, and hotspots of KRAS, BRAF, and GNAS in 64 cases by targeted sequencing. KRAS and GNAS were additionally analyzed in 86 STK11-normal IPMNs using digital-PCR. RESULTS: Consistent loss or reduction of STK11 expression was observed in 26 of 184 (14%) IPMNs. These STK11-aberrant IPMNs were 17 of 45 (38%) pancreatobiliary, 8 of 27 (30%) oncocytic, 1 of 54 (2%) gastric, and 0 of 58 (0%) intestinal subtypes ( P = 8.5E-11), and 20 of 66 (30%) invasive, 6 of 74 (8%) high-grade, and 0 of 44 (0%) low-grade ( P = 3.9E-06). Sixteen somatic STK11 mutations (5 frameshift, 6 nonsense, 1 splicing, and 4 missense) were detected in 15/26 STK11-aberrant IPMNs ( P = 4.1E-06). All STK11-aberrantIPMNs were GNAS -wild-type and 96% of them were KRAS or BRAF -mutant.Morphologically, STK11-aberrant IPMNs presented "fern-like" arborizing papillae with thin fibrovascular core. Phosphorylated-AMPKa was down-regulated in STK11-aberrant IPMNs (92%, P = 6.8E-11). Patients with STK11-aberrant IPMNs showed poorer survival than patients with STK11-normal IPMNs ( P = 3.6E-04 overall; P = 6.1E-04 disease-free). CONCLUSION: STK11 may play a canonical role in malignant progression and poor survival of patients with IPMNs. Aberrant STK11-driven phosphorylated AMPK downregulation may provide therapeutic opportunities with mTOR inhibitors/AMPK activators.

Negative prognostic impact of sarcopenia before and after neoadjuvant chemotherapy for pancreatic cancer.

OBJECTIVES: To elucidate the prognostic impact of sarcopenia before and after neoadjuvant chemotherapy (NAC) for pancreatic cancer (PC). METHODS: We retrospectively studied 75 consecutive PC patients who underwent neoadjuvant gemcitabine plus S-1 combination therapy followed by pancreatectomy between 2008 and 2016. According to the skeletal muscle volume index (SMI), the patients were divided into the muscle attenuation group (MAG) and normal group (NG) before or after NAC. Prognostic factors for overall survival (OS) were analyzed by Cox proportional hazards models. RESULTS: The MAG showed significantly poorer OS than the NG before and after NAC. Pre-NAC, median OS was 20.0 months in the MAG versus 49.0 months in the NG (p = 0.006). Post-NAC, median OS was 21.3 months in the MAG versus 48.8 months in the NG (p = 0.014). Multivariate analysis, excluding muscle attenuation after NAC because of confounding factors and lower hazard ratio (2.08, 95% confidence interval: 1.14-3.78, p = 0.016) than that before NAC (2.14, 1.23-3.70, p = 0.007) by univariate analysis, revealed the following independent prognostic factors: muscle attenuation pre-NAC (2.25, 1.26-4.05, p = 0.007); borderline resectability (1.96, 1.04-3.69, p = 0.038); operative blood loss (2.60, 1.38-4.88, p = 0.003); and distant metastasis (3.31, 1.40-7.82, p = 0.006). CONCLUSIONS: Sarcopenia before and after NAC for PC is suggested to be a poor prognostic factor, with a stronger impact before than after NAC.

Learning curve of robotic rectal surgery using risk-adjusted cumulative summation: a 5-year institutional experience.

PURPOSE: Outline learning phases of robot-assisted laparoscopic surgery for rectal cancer and compare surgical and clinical outcomes between each phase of robot-assisted laparoscopic surgery and the mastery phase of conventional laparoscopic surgery. METHODS: From 2015 to 2020, 210 patients underwent rectal cancer surgery at Sendai Medical Center. We performed conventional laparoscopic surgery in 110 patients and, laparoscopic surgery in 100 patients. The learning curve was evaluated using the cumulative summation method, risk-adjusted cumulative summation method, and logistic regression analysis. RESULTS: The risk-adjusted cumulative summation learning curve was divided into three phases: phase 1 (cases 1-48), phase 2 (cases 49-80), and phase 3 (cases 81-100). Duration of hospital stay (13.1 days vs. 18.0 days, respectively; p = 0.016) and surgery (209.1 min vs. 249.5 min, respectively; p = 0.045) were significantly shorter in phase 3 of the robot-assisted laparoscopic surgery group than in the conventional laparoscopic surgery group. Blood loss volume was significantly lower in phase 1 of the robot-assisted laparoscopic surgery group than in the conventional laparoscopic surgery group (17.7 ml vs. 79.7 ml, respectively; p = 0.036). The International Prostate Symptom Score was significantly lower in the robot-assisted laparoscopic surgery group (p = 0.0131). CONCLUSIONS: Robot-assisted laparoscopic surgery for rectal cancer was safe and demonstrated better surgical and clinical outcomes, including a shorter hospital stay, less blood loss, and a shorter surgical duration, than conventional laparoscopic surgery. After experience with at least 80 cases, tactile familiarity can be acquired from visual information only (visual haptic feedback). CLINICAL TRIAL REGISTRATION: UMIN reference no. UMIN000019857.

TWIST1 is a prognostic factor for neoadjuvant chemotherapy for patients with resectable pancreatic cancer: a preliminary study.

Recent advances in the development of chemotherapies have helped improve the prognosis of pancreatic ductal adenocarcinoma (PDAC). However, predicting factors for the outcomes of chemotherapies (either gemcitabine or S-1) have not yet been established. We analyzed the expression of 4 major epithelial-to-mesenchymal transition-inducing transcription factors in 38 PDAC patients who received adjuvant chemotherapy after radical resection to examine the association with patients' prognoses. The TWIST1-positive group showed a significantly poorer prognosis than the TWIST1-negative group for both the relapse-free survival (median survival time [MST] of 8.9 vs. 18.5 months, P = 0.016) and the overall survival (MST of 15.2 vs. 33.4 months, P = 0.023). A multivariate analysis revealed that TWIST1 positivity was an independent prognostic factor for a poor response to adjuvant chemotherapies (hazard ratio 2.61; 95% confidence interval 1.10-6.79; P = 0.029). These results suggest that TWIST1 can be utilized as an important poor prognostic factor for radically resected PDAC patients with adjuvant chemotherapy, potentially including neoadjuvant therapy using these agents.

[Treatment Experience of Chemotherapy and Carbon-Ion Radiotherapy followed by Curative Conversion Surgery for Initially Locally Advanced Unresectable Pancreatic Cancer after Distal Gastrectomy].

BACKGROUND: Carbon-ion radiotherapy(CIRT)has an advantage over conventional radiotherapy by its dose distribution and biological effect for locally advanced unresectable pancreatic cancer(UR-PC). Conversion surgery(CS)might be attempted for UR-PC with favorable response by chemotherapy and radiotherapy. CASE PRESENTATION: A 67-year-old female who have a history of distal gastrectomy. CT scan revealed locally advanced UR-PC with invasion to celiac artery, 60 mm in size. Systemic chemotherapy with gemcitabine and nab-paclitaxel was continued for 15 months, showing decrease of tumor markers and radiological shrinkage of the tumor. The patient was referred to our hospital for surgical consultation. Since there was no metastasis in staging laparoscopy, CIRT with gemcitabine was administered for 3 weeks. After completion of CIRT, distal pancreatectomy with celiac axis resection and total remnant gastrectomy for direct invasion of the tumor was performed as CS, resulting R0 resection. Her postoperative course was uneventful with 17 days of hospital stay. DISCUSSION: CS after CIRT was safely performed. Clinical trial of total neoadjuvant therapy with systemic chemotherapy, CIRT, followed by CS for locally advanced CIRT is ongoing in our hospital. CIRT could be an effective treatment in locally advanced UR-PC in the context of multi-modal treatment including CS.

Impact of Tumor-Derived DNA Testing in Peritoneal Lavage of Pancreatic Cancer Patients with and Without Occult Intra-Abdominal Metastases.

BACKGROUND: The fractional abundance of tumor-derived DNA in body fluids depends on the metastatic sites and the degree of expansion. We aimed to assess the clinical significance of tumor-derived DNA testing in the peritoneal lavage of patients with pancreatic cancer. METHODS: The prevalence and abundance of tumor-derived DNA was assessed in 204 subjects with ascites by peritoneal lavage (AS) and the evaluable paired plasma (PL) from 149 pancreatic cancer patients undergoing abdominal exploration. Genetic profiles were evaluated by next-generation sequencing, and prognostic impact was assessed using Cox proportional hazard models. RESULTS: Of 204 subjects, AS samples from patients with peritoneal dissemination (PER+) and positive cytology (CY+) showed significantly higher prevalence and abundance of tumor-derived DNA than those with negative counterparts. Tumor-derived DNA prevalence and abundance in AS were more likely to be higher than in paired PL in a subgroup of patients with PER+ and CY+, respectively. Next-generation sequencing revealed concordant or discrepant mutational patterns between the AS and PL samples. Multivariate analysis showed that both tumor-derived DNA in AS (hazard ratio [HR] 3.940, p = 0.009) and PL (HR 2.936, p = 0.026) were independently associated with poor survival in treatment-naïve patients. In patients who underwent resection, tumor-derived DNA positivity in the AS was more predictive of early recurrence than in PL. CONCLUSIONS: Tumor-derived DNA in AS can serve as characterizing the genetic profiles of tumor cells attributable to the development of PER+ and predicting the minimal residual disease and early recurrence in patients with pancreatic cancer.

[Pathological Complete Response and Long-Term Survival of a Gastric Neuroendocrine Carcinoma Patient Treated by Neoadjuvant Chemotherapy].

A 64-year-old man with gastric tumor in the antrum had been diagnosed with gastric neuroendocrine carcinoma(NEC) by biopsy and multiple lymph node metastases(#3 and #6)by abdominal computed tomography. After staging laparoscopy showed that there were no non-curative factors, neoadjuvant chemotherapy(S-1/cisplatin[CDDP]: 2 courses)and distal gastrectomy and D2 lymph node dissection were performed. The pathological diagnosis was shown as pathological complete response(pCR). After adjuvant chemotherapy(S-1/CDDP: 2 courses, S-1: 6 courses)was administered, the patient is alive at 8 years without recurrence.

[A Case of Dedifferentiated Liposarcoma with Reducing Surgery Followed by Chemotherapy and Additional Reducing Surgery].

Dedifferentiated liposarcoma shows poor prognosis because of poor resectability due to aggressive invasion of adjacent organs with multicentric growth and its low sensitivity to chemotherapy. We report herein a case of a giant dedifferentiated liposarcoma, successfully treated by pancreaticoduodenectomy(PD)for tumor reduction and chemotherapy for 1 year after surgery, followed by additional surgery for tumor reduction. The patient is a woman in 50s. CT showed an 18.5×9 cm main mass surrounding the superior mesenteric artery(SMA and SMV)with multiple tumors in the pelvis. Needle biopsy revealed dedifferentiated liposarcoma. Although complete resection or chemotherapy was not feasible, surgery was performed for local control and introduction of chemotherapy. The main tumor was resected by PD with SMV resection and right colectomy. Chemotherapy with doxorubicin followed by eribulin was administered after surgery. The residual lesions were controlled for 1 year. Partial resection of the tumors in the mesentery was performed. Eribulin were administered starting postoperatively. One year and 10 months after the initial surgery, there was no progress in residual disease. Although R2 resection for dedifferentiated liposarcoma shows extremely poor prognosis. Even when complete resection would be difficult, multidisciplinary treatment including debulking surgery might be effective for disease control.

[A Case of Long-Term Survival by Multidisciplinary Surgical Treatment for Metastatic Multi-Organ Metastasis after Radical Resection of Esophageal Cancer].

A 78-year-old man with advanced thoracic esophageal cancer underwent radical esophagectomy after neoadjuvant chemotherapy with cisplatin plus 5-FU. He had left adrenal metastasis 10 months after surgery and removed it, but 3 months later he had liver metastases. After 2 courses of chemotherapy with nedaplatin plus 5-FU, resection was performed. One course of nedaplatin plus 5-FU for adjuvant chemotherapy was added, but the patient was followed up without another chemotherapy after surgery because of intestinal obstruction due to infection and increase of the lymphatic cyst in the abdominal cavity. Six months after the liver resection, nodules appeared in the right lung, and 4 months later, multiple nodules extending to both lungs were observed. Therefore, it was judged that there were multiple lung metastases, and administration of nivolumab was started. He has been 3 years since the recurrence of esophageal cancer and 17 months after the start of nivolumab administration, but the recurrence lesion is only progressing to lung metastasis.

Silencing of LRRFIP1 enhances the sensitivity of gemcitabine in pancreatic cancer cells by activating JNK/c-Jun signaling.

BACKGROUND: The epithelial-mesenchymal transition (EMT) in cancer cells has been shown to closely associate with the survival and drug resistance of cancer cells. We recently provided evidence that Wnt signal activator leucine-rich repeat in flightless-1-interacting protein 1 (LRRFIP1) regulates EMT in pancreatic cancer. LRRFIP1 silencing inhibits the translocation of ß-catenin to the nucleus, which led to reverse EMT in cancer cells. It was suggested that LRRFIP1 was implicated in gemcitabine sensitivity by regulating EMT signaling. METHODS: Gemcitabine chemosensitivity was investigated in LRRFIP1-knockdown pancreatic cancer cells (PANC-1 and MIA Paca-2). In addition, the effects of LRRFIP1 knockdown on JNK/SAPK (stress activated-protein kinase) signaling and apoptosis were evaluated. RESULTS: LRRFIP1 silencing accelerates gemcitabine-induced caspase activity and cell death in pancreatic cancer cells. It was also revealed that gemcitabine-induced phosphorylation of c-Jun N-terminal kinase (JNK) and c-Jun were increased in LRRFIP1 knockdown cells. The activation of JNK/c-Jun in LRRFIP1-knockdown cells was significantly diminished by the inhibition of Rac activity. It was confirmed that the acquisition of gemcitabine sensitivity by LRRFIP1 silencing largely depends on the stimulation of JNK/SAPK (stress activated-protein kinase) signaling. CONCLUSIONS: Our findings suggest that reversing EMT and transient activation of JNK might be essential for the gemcitabine sensitivity in LRRFIP1 knockdown pancreatic cancer cells. Our discoveries highlight the potential role of LRRFIP1 in the chemosensitivity related to the regulation of EMT signaling.

Prognostic value of an inflammation-based nutritional score for patients with initially unresectable pancreatic adenocarcinoma undergoing conversion surgery following chemo-/radiotherapy.

PURPOSE: To clarify the prognostic value of the preoperative nutrition status of patients undergoing conversion surgery (CS) for initially unresectable pancreatic adenocarcinoma (UR-PA). METHODS: The subjects of this retrospective study were 41 consecutive patients with initially UR-PA treated with chemo-/radiotherapy and subsequent CS between 2007 and 2014, at Tohoku University Hospital. The preoperative Glasgow Prognostic Score (GPS) was 0, conveying normal nutrition, in 25 patients (N group) and 1-2, conveying malnutrition, in 16 patients (M group). The clinicopathological factors influencing overall survival were defined by uni- and multivariate analyses. RESULTS: The M group had a significantly worse prognosis than the N group (median overall survival (mOS) 9.6 vs 40.7 months, p = 0.001). Multivariate analysis identified a GPS of 1-2 as an independent predictor of worse prognosis [hazard ratio (HR)3.437, p = 0.032], followed by CA19-9 elevation before CS (HR4.089, p = 0.012) and pathological lymph node metastases (HR2.314, p = 0.046). Patients who maintained a favorable nutritional status (GPS 0) during preoperative treatment had a significantly better prognosis, whereas those whose nutritional status deteriorated (elevated to GPS 1-2) had poorer survival (mOS 40.7 vs. 9.7 months, p = 0.003) CONCLUSION: Preoperative malnutrition status (GPS 1-2) is considered an independent predictor of a worse prognosis for patients undergoing CS for initially UR-PA.

Staging laparoscopy is mandatory for the treatment of pancreatic cancer to avoid missing radiologically negative metastases.

PURPOSE: Staging laparoscopy is considered useful for determining treatment plans for advanced pancreatic cancer. However, the indications for staging laparoscopy are not clear. This study aimed to evaluate the safety of staging laparoscopy and its usefulness for detecting distant metastases in patients with pancreatic cancer. METHODS: A total of 146 patients with pancreatic cancer who underwent staging laparoscopy between 2013 and 2019 were analyzed. Staging laparoscopy was performed in all pancreatic cancer patients in whom surgery was considered possible. RESULTS: In this cohort, 42 patients (29%) were diagnosed with malignant cells on peritoneal lavage cytology, 9 (6%) had peritoneal dissemination, and 11 (8%) had liver metastases. A total of 48 (33%) had radiologically negative metastases. On a multivariate analysis, body and tail cancer [odds ratio (OR) 5.00, 95% confidence interval (CI) 2.15-11.6, p < 0.001], high CA19-9 level [OR 4.04, 95% CI 1.74-9.38, p = 0.001], and a resectability status of unresectable (OR 2.31, 95% CI 1.03-5.20, p = 0.04) were independent risk factors for radiologically negative metastases. CONCLUSIONS: Staging laparoscopy can be safely performed and is useful for the diagnosis of radiologically negative metastases. Staging laparoscopy should be routinely performed for the accurate diagnosis of pancreatic cancer patients before pancreatectomy and/or local treatment, such as radiotherapy.

Quantitative digital image analysis of somatostatin receptor 2 immunohistochemistry in pancreatic neuroendocrine tumors.

Immunohistochemical analysis of somatostatin receptor 2 (SSTR2) provides important information regarding the potential therapeutic efficacy of somatostatin analogues (SSAs) in patients with neuroendocrine tumors. HER2 scoring has been proposed to interpret SSTR2 immunoreactivity but their reproducibility was relatively low because of its intrinsic subjective nature. Digital image analysis (DIA) has recently been proposed as an objective and more precise method of evaluating immunoreactivity. Therefore, in this study, we used DIA for analyzing SSTR2 immunoreactivity in pancreatic neuroendocrine tumors (PanNETs) to obtain its H score and "(%) strong positive cells" and compared the results with those of manually obtained HER2 scores. Membranous SSTR2 immunoreactivity evaluated by DIA was calculated by two scales as: "Membrane Optical Density" and "Minimum Membrane Completeness". PanNETs with HER2 score of > 2 demonstrated the highest concordance with results of "(%) strong positive cells" obtained by DIA when "Minimum Membrane Completeness" was tentatively set at 80%. The SSTR2 immunoreactivity, evaluated based on all scoring systems, was different between grades G1 and G2 in insulinoma but not in non-functional PanNETs. DIA provided reproducible results of SSTR2 immunoreactivity in PanNETs and yielded important information as to the potential application of SSAs.

[A Case of Long-Term Survival Achieved after Nivolumab Treatment for Recurrence of Postoperative Advanced Gastric Cancer].

A 75-year-old man with a Type 3 advanced gastric cancer in the middle gastric body and paraaortic lymph node swelling was treated chemotherapy. After treatment, we performed an exploratory laparotomy and curative total gastrectomy. As adjuvant chemotherapy, S-1 treatment was administrated for 4 courses but multiple metastases from left supraclavicular to paraaortic lymph nodes. First, Cape plus CDDP plus T-mab therapy treated. Because of acute renal failure, Cape plus L-OHP plus T-mab was administrated but response evaluation was PD. In the second-line therapy, Ramucirumab plus paclitaxel was performed 4 courses. Third, we administrated Nivolumab. After 6 courses, response evaluation was PR and we continued 24 courses. At the same time, there was acute-onset Nivolumab-induced organizing pneumonia and we treated steroid pulse, azithromycin and introduced home oxygen therapy. At the present, 47 months long-term survival achieved after Nivolumab treatment.

[A Successful Case of Pancreaticoduodenectomy after Neoadjuvant Therapy for Pancreatic Head Cancer with Acute Pancreatitis Due to Iatrogenic Injury of the Pancreatic Duct].

A 64-year-old woman was referred to our hospital for treatment of pancreatic head cancer with acute pancreatitis due to iatrogenic injury of the pancreatic duct during endoscopic retrograde cholangiopancreatography. In addition to a 28 mm pancreatic head tumor, soft tissue shadow and fluid collection surrounding the superior mesenteric artery(SMA)due to pancreatitis were observed in the abdominal CT scan. The tumor was histologically diagnosed as adenocarcinoma by endoscopic ultrasound-guided fine needle aspiration. Neoadjuvant chemotherapy with gemcitabine and S-1 was performed to control the progression of the pancreatic cancer and improve the inflammatory changes for reduction of the operative risk. After 2 courses of neoadjuvant chemotherapy, abdominal CT scan revealed stable disease according to the Response Evaluation Criteria in Solid Tumors and attenuation of the inflammatory changes surrounding the SMA. Then, subtotal stomach- preserving pancreaticoduodenectomy was performed without the difficulty of peeling around the SMA in spite of the old inflammatory changes. Histological examination of the resected specimen showed R0 resection. The patient was discharged 18 days after surgery without any complications and is surviving 9 months postoperatively without any recurrence. Neoadjuvant chemotherapy was helpful for disease control and improvement of the inflammatory changes.

Epigenetic inactivation of IRX4 is responsible for acceleration of cell growth in human pancreatic cancer.

Epigenetic gene silencing by aberrant DNA methylation is one of the important mechanisms leading to loss of key cellular pathways in tumorigenesis. Methyl-CpG-targeted transcriptional activation (MeTA) reactivates hypermethylation-mediated silenced genes in a different way from DNA-demethylating agents. Microarray coupled with MeTA (MeTA-array) identified seven commonly hypermethylation-mediated silenced genes in 12 pancreatic ductal adenocarcinoma (PDAC) cell lines. Among these, we focused on IRX4 (Iroquois homeobox 4) because IRX4 is located at chromosome 5p15.33 where PDAC susceptibility loci have been identified through genome-wide association study. IRX4 was greatly downregulated in all of the analyzed 12 PDAC cell lines by promoter hypermethylation. In addition, the IRX4 promoter region was found to be frequently and specifically hypermethylated in primary resected PDACs (18/28: 64%). Reexpression of IRX4 inhibited colony formation and proliferation in two PDAC cell lines, PK-1 and PK-9. In contrast, knockdown of IRX4 accelerated cell proliferation in an IRX4-expressing normal pancreatic ductal epithelial cell line, HPDE-1. Because IRX4 is a sequence-specific transcription factor, downstream molecules of IRX4 were pursued by microarray analyses utilizing tetracycline-mediated IRX4 inducible PK-1 and PK-9 cells; CRYAB, CD69, and IL32 were identified as IRX4 downstream candidate genes. Forced expression of these genes suppressed colony formation abilities for both PK-1 and PK-9. These results suggest that DNA methylation-mediated silencing of IRX4 contributes to pancreatic tumorigenesis through aberrant transcriptional regulation of several cancer-related genes.

Methylation-mediated silencing of the LIM homeobox 6 (LHX6) gene promotes cell proliferation in human pancreatic cancer.

Epigenetic gene silencing by aberrant DNA methylation leads to loss of key cellular pathways in tumorigenesis. DNA methylation-mediated silenced genes in pancreatic cancer were searched for using the methyl-CpG targeted transcriptional activation (MeTA) method, and LHX6 (LIM homeobox 6), a transcription factor involved in embryogenesis and head development, was selected as a strong candidate gene. LHX6 was downregulated in most of the pancreatic cancer cell lines (83%, 10/12), mainly through promoter hypermethylation and histone deacetylation. Furthermore, LHX6 was methylated in primary pancreatic cancer specimens (57%, 16/28) in a tumor-specific manner. Re-expression of LHX6 inhibited colony formation and proliferation in LHX6 low-expressing pancreatic cancer cell lines, PK-1 and PK-9. In contrast, knockdown of LHX6 accelerated cell proliferation in LHX6 high-expressing pancreatic cancer cell lines, PCI-35 and MIA PaCa-2. In order to analyze LHX6 downstream genes, we performed microarray analyses using LHX6 inducible PK-1 and PK-9 and found that LHX6 induction upregulated several genes that had tumor suppressive functions. Among these, we focused on TFPI2 (Tissue factor pathway inhibitor-2) and found that TFPI2 was greatly downregulated in all twelve pancreatic cancer cell lines. Our present results suggest that epigenetic inactivation of LHX6 plays an important role in pancreatic tumorigenesis by promoting cell proliferation through aberrant transcriptional regulation of several cancer-related genes.

The Function and Prognostic Significance of Cripto-1 in Colorectal Cancer.

Cripto-1 is a plasma membrane protein which is not expressed in adult tissue, but some tumors are accompanied by re-activation. We studied the clinical and biological significance of Cripto-1 in colorectal cancer. Cripto-1 was positive in 68 out of 192 cases (35%) by immunohistochemistry. Cripto-1 expression was correlated with worse prognosis and was an independent prognostic factor. Cripto-1-silenced colorectal cancer cell lines had reduced cell proliferation, migration, and activation of Akt and MAPK signaling pathways in vitro, and decreased tumor growth and lymph node metastasis in vivo. Cripto-1 could be a useful prognostic biomarker and therapeutic target in colorectal cancer.