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ABSTRACTGastrointestinal stromal tumor (GIST) with a mutation in exons 11 and 17 of c-kit is a rare type of sarcoma. The aim of this study was to determine drug sensitivity for a regionally-recurrent case of GIST using a patient-derived orthotopic xenograft (PDOX) model. The PDOX model was established in the anterior wall of the stomach. GIST PDOX models were randomized into 5 groups of 6 mice each when the tumor volume reached 60 mm3: G1, control group; G2, imatinib group (oral administration (p.o.), daily, for 3 weeks); G3, sunitinib group (p.o., daily, for 3 weeks); G4, regorafenib (p.o., daily, for 3 weeks); G5, pazopanib (p.o., daily, for 3 weeks). All mice were sacrificed on day 22. Tumor volume was evaluated on day 0 and day 22 by laparotomy. Body weight were measured 2 times per week. Though regorafenib is third-line therapy for GIST, it was the most effective drug and regressed the tumor significantly (p < 0.001). Sunitinib suppressed tumor growth compared to the control group (p = 0.002). Imatinib, first-line therapy for GIST, and pazopanib did not have significant efficacy compared to the control group (p = 0.886, p = 0.766). The implications of this result is discussed for GIST patients.

Laparoscopic surgery has been widely accepted for the treatment of colorectal cancer; however, long-term outcomes in elderly patients remain controversial. The midterm results of a randomized trial comparing open surgery with laparoscopic surgery in elderly patients with colorectal cancer are presented. This was a randomized trial comparing open surgery with laparoscopic surgery in elderly patients with colorectal cancer. The primary outcome was complication rate, and secondary outcomes included 3-year recurrence-free survival and overall survival. A total of 200 patients were randomly assigned to open surgery or laparoscopic surgery between 2008 and 2012. The main study objective was to compare the midterm outcomes of open surgery with those of laparoscopic surgery in elderly patients with colorectal cancer. This trial is registered with Clinical Trials.gov (NCT01862562). There were no differences between the laparoscopic surgery group and open surgery group in the 3-year overall survival rate (91.5% for laparoscopic surgery vs. 90.6% for open surgery, p= 0.638) or the 3-year recurrence-free survival rate (84.8% for laparoscopic surgery vs. 88.2% for open surgery, p= 0.324). The local recurrence rate was significantly higher in the laparoscopic surgery group than in the open surgery group in rectal cancer (13.8% for laparoscopic surgery vs. 0% for open surgery, p= 0.038). In subgroup analysis according to tumor location, there were no significant differences in the 3-year overall survival rate or 3-year recurrence-free survival rate between the two treatment groups. The midterm outcomes of laparoscopic surgery are similar to those of open surgery in elderly patients with colorectal cancer.

The XPA1 human pancreatic cancer cell line is dimorphic, with spindle stem-like cells and round non-stem cells. We report here the in vitro IC50values of stem-like and non-stem XPA1 human pancreatic cells cells for: (1) 5-fluorouracil (5-FU), (2) cisplatinum (CDDP), (3) gemcitabine (GEM), and (4) tumor-targeting Salmonella typhimuriumA1-R (A1-R). IC50values of stem-like XPA1 cells were significantly higher than those of non-stem XPA1 cells for 5-FU (P= 0.007) and CDDP (P= 0.012). In contrast, there was no difference between the efficacy of A1-R on stem-like and non-stem XPA1 cells. In vivo, 5-FU and A1-R significantly reduced the tumor weight of non-stem XPA1 cells (5-FU; P= 0.028; A1-R; P= 0.011). In contrast, only A1-R significantly reduced tumor weight of stem-like XPA1 cells (P= 0.012). The combination A1-R with 5-FU improved the antitumor efficacy compared with 5-FU monotherapy on the stem-like cells (P= 0.004). The results of the present report indicate A1-R is a promising therapy for chemo-resistant pancreatic cancer stem-like cells.

Malignant glioma tumors are the most common primary central nervous system tumors. Despite the multidisciplinary approach to treatment, prognosis remains poor. In this study, we demonstrated that the Salmonella typhimuriumA1-R tumor-targeting strain can inhibit and eradicate human glioma in an orthotopic nude-mouse model. S. typhimuriumA1-R was administered by injection through a craniotomy open-window or intravenously in nude mice. To establish the model, 2 x 105 U87-RFP human glioma cells were injected stereotactically into the mouse brain through the craniotomy open window. Two weeks after glioma-cell implantation, mice were treated with S. typhimuriumA1-R [2 x 107CFU/200 μl intravenous injection (i.v.) or 1 x 106CFU/1 μl intracranial injection (i.c.)] once a week for 3 weeks. Brain tumors were observed by fluorescence imaging through the craniotomy open window over time. S. typhimuriumA1-R, administered i.c., inhibited brain tumor growth 7.6-fold compared with untreated mice (p = 0.009) and improved survival 73% (p = 0.001). Two of ten mice appeared to have their tumors eradicated. Intravenous administration of S. typhimuriumA1-R was not effective. The craniotomy open window enabled observation of tumor growth in the brain in real time in both treated and untreated mice. The results of the present study demonstrate that bacterial therapy of brain cancer is a novel, effective and safe treatment strategy in a highly treatment-resistance cancer.

We have previously developed a telomerase-specific replicating adenovirus expressing GFP (OBP-401), which can selectively label tumors in vivo with GFP. Intraperitoneal (i.p.) injection of OBP-401 specifically labeled peritoneal tumors with GFP, enabling fluorescence visualization of the disseminated disease and real-time fluorescence surgical navigation. However, the technical problems with removing all cancer cells still remain, even with fluorescence-guided surgery. In this study, we report imaging of tumor recurrence after fluorescence-guided surgery of tumors labeled in vivo with the telomerase-dependent, GFP-containing adenovirus OBP-401.. Recurrent tumor nodules brightly expressed GFP, indicating that initial OBP-401-GFP labeling of peritoneal disease was genetically stable, such that proliferating residual cancer cells still express GFP. In situ tumor labeling with a genetic reporter has important advantages over antibody and other non-genetic labeling of tumors, since residual disease remains labeled during recurrence and can be further resected under fluorescence guidance.

Supplemental Digital Content is available in the text.

Supplemental Digital Content is available in the text.