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Gastrointestinal stromal tumor (GIST) is a refractory disease in need of novel efficacious therapy. The aim of our study was to evaluate the effectiveness of tumor-targeting Salmonella typhimurium A1-R ( S. typhimurium A1-R) using on a patient derived orthotopic xenograft (PDOX) model of imatinib-resistant GIST. The GIST was obtained from a patient with regional recurrence, and implanted in the anterior gastric wall of nude mice. The GIST PDOX mice were randomized into 3 groups of 6 mice each when the tumor volume reached 60 mm 3 : G1, control group; G2, imatinib group (oral administration [p.o.], daily, for 3 weeks); G3, S. typhimurium A1-R group (intravenous [i.v.] injection, weekly, for 3 weeks). All mice from each group were sacrificed on day 22. Relative tumor volume was estimated by laparotomy on day 0 and day 22. Body weight of the mouse was evaluated 2 times per week. We found that S. typhimurium A1-R significantly reduced tumor growth in contrast to the untreated group ( P = 0.001). In addition, we found that S. typhimurium A1-R was more effective compared to imatinib ( P = 0.013). Furthermore, Imatinib was not significantly effective compared to the control group (P = 0.462). These results indicate that S. typhimurium A1-R may be new effective therapy for imatinib-resistant GIST and therefore a good candidate for clinical development of this disease.

Synovial sarcoma (SS) is a recalcitrant subgroup of soft tissue sarcoma (STS). A tumor from a patient with high grade SS from a lower extremity was grown orthotopically in the right biceps femoris muscle of nude mice to establish a patient-derived orthotopic xenograft (PDOX) mouse model. The PDOX mice were randomized into the following groups when tumor volume reached approximately 100 mm 3 : G1, control without treatment; G2, doxorubicin (DOX) (3 mg/kg, intraperitoneal [i.p.] injection, weekly, for 2 weeks; G3, rMETase (100 unit/mouse, i.p., daily, for 2 weeks); G4 DOX (3mg/kg), i.p. weekly, for 2 weeks) combined with rMETase (100 unit/mouse, i.p., daily, for 2 weeks). On day 14 after treatment initiation, all therapies significantly inhibited tumor growth compared to untreated control, except DOX: (DOX: p = 0.48; rMETase: p < 0.005; DOX combined with rMETase < 0.0001). DOX combined with rMETase was significantly more effective than both DOX alone ( p < 0.001) and rMETase alone ( p < 0.05). The relative body weight on day 14 compared with day 0 did not significantly differ between any treatment group or untreated control. The results indicate that r-METase can overcome DOX-resistance in this recalcitrant disease., Competing Interests: CONFLICTS OF INTEREST None.

Undifferentiated spindle-cell sarcoma (USCS) is a recalcitrant -cancer in need of individualized therapy. A high-grade USCS from a striated muscle of a patient was grown orthotopically in the right biceps femoris muscle of nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. In a previous study, we evaluated the efficacy of standard first-line chemotherapy of doxorubicin (DOX), gemcitabine (GEM) combined with docetaxel (DOC), compared to pazopanib (PAZ), a multi-targeting tyrosine-kinase inhibitor, in an USCS PDOX model. In the present study, mice-bearing the USCS PDOX tumors were randomized into the following groups when tumor volume reached 100 mm 3 : G1, untreated control without treatment; G2, DOX (3 mg/kg, intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, L-methionine α-deamino-γ-mercaptomethane lyase (recombinant methioninase [rMETase]) (100 U/mouse, i.p., daily, for 2 weeks). Tumor size and body weight were measured with calipers and a digital balance twice a week. The methionine level of supernatants derived from sonicated tumors was also measured. rMETase inhibited tumor growth, measured by tumor volume, compared to untreated controls and the DOX-treated group on day 14 after initiation of treatment: control (G1): 347.6 ± 88 mm 3 ; DOX (G2): 329.5 ± 79 mm 3 , P = 0.670; rMETase (G3): 162.6 ± 51 mm 3 , P = 0.0003. The mouse body weight of the treated mice was not significantly different from the untreated controls. Tumor L-methionine levels were reduced after the rMETase-treatment compared to untreated control and pre-rMETase treatment. We previously reported efficacy of rMETase against Ewing's sarcoma and melanoma in a PDOX models. These studies suggest clinical development of rMETase, especially in recalcitrant cancers such as sarcoma., (© 2017 Wiley Periodicals, Inc.)

An excessive requirement for methionine (MET) for growth, termed MET dependence, appears to be a general metabolic defect in cancer. We have previously shown that cancer-cell growth can be selectively arrested by MET restriction such as with recombinant methioninase (rMETase). In the present study, we utilized patient-derived orthotopic xenograft (PDOX) nude mouse models with pancreatic cancer or melanoma to determine the relationship between intra-tumor MET level and tumor size. After the tumors grew to 100 mm 3 , the PDOX nude mice were divided into two groups: untreated control and treated with rMETase (100 units, i.p., 14 consecutive days). On day 14 from initiation of treatment, intra-tumor MET levels were measured and found to highly correlate with tumor volume, both in the pancreatic cancer PDOX ( p <0.0001, R 2 =0.89016) and melanoma PDOX ( p <0.0001, R 2 =0.88114). Tumors with low concentration of MET were smaller. The present results demonstrates that patient tumors are highly dependent on MET for growth and that rMETase effectively lowers tumor MET., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.

Doxorubicin (DOX) is often first-line treatment of undifferentiated/unclassified soft tissue sarcoma (USTS). However, the DOX response rate for USTS patients is low. Individualized precision-medicine technology that could identify DOX responders as well as non-responders would be of high value to cancer patients. In the present study, we established 5 patient-derived orthotopic xenograft (PDOX) nude mouse models from 5 USTS patients and evaluated the efficacy of DOX in each PDOX model. USTS's were grown orthotopically in the right thigh of nude mice to establish the PDOX models. Two weeks after implantation, the mouse models were randomized into two groups of 8 mice each: untreated control; and DOX (3 mg/kg, i.p., once a week for 2 weeks). DOX showed significant growth inhibition in only 2 USTS PDOX models out of 5 (p = 0.0054, p = 0.0055, respectively) on day 14 after initiation. DOX was ineffective in the other 3 PDOX models. However, even in the DOX-sensitive cases, DOX could not regress the PDOX tumors responding to treatment. The present study has important implications since this is the first in vivo study to compare the DOX sensitivity for USTS on multiple patient tumors. We showed that only two of five USTS were responsive to DOX, despite DOX being first line chemotherapy for USTS. The 3 resistant cases should not be treated with DOX clinically, in order to spare the patients' unnecessary toxicity. This PDOX model is useful for precise individualized drug sensitivity testing, especially for rare heterogeneous recalcitrant sarcomas such as USTS.

Pancreatic cancer is a recalcitrant disease. Gemcitabine (GEM) is the most widely-used first-line therapy for pancreatic cancer, but most patients eventually fail. Transformative therapy is necessary to significantly improve the outcome of pancreatic cancer patients. Tumors have an elevated requirement for methionine and are susceptible to methionine restriction. The present study used a patient-derived orthotopic xenograft (PDOX) nude mouse model of pancreatic cancer to determine the efficacy of recombinant methioninase (rMETase) to effect methionine restriction and thereby overcome GEM-resistance. A pancreatic cancer obtained from a patient was grown orthotopically in the pancreatic tail of nude mice to establish the PDOX model. Five weeks after implantation, 40 pancreatic cancer PDOX mouse models were randomized into four groups of 10 mice each: untreated control (n = 10); GEM (100 mg/kg, i.p., once a week for 5 weeks, n = 10); rMETase (100 units, i.p., 14 consecutive days, n = 10); GEM+rMETase (GEM: 100 mg/kg, i.p., once a week for 5 weeks, rMETase: 100 units, i.p., 14 consecutive days, n = 10). Although GEM partially inhibited PDOX tumor growth, combination therapy (GEM+rMETase) was significantly more effective than mono therapy (GEM: p = 0.0025, rMETase: p = 0.0010). The present study is the first demonstrating the efficacy of rMETase combination therapy in a pancreatic cancer PDOX model to overcome first-line therapy resistance in this recalcitrant disease.

Gastrointestinal 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 mm 3 : 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.

The elevated methionine (MET) use by cancer cells is termed MET dependence and may be the only known general metabolic defect in cancer. Targeting MET by recombinant methioninase (rMETase) can arrest the growth of cancer cells in vitro and in vivo. We previously reported that rMETase, administrated by intra-peritoneal injection (ip-rMETase), could inhibit tumor growth in a patient-derived orthotopic xenograft (PDOX) model of a BRAF-V600E mutant melanoma. In the present study, we compared ip-rMETase and oral rMETase (o-rMETase) for efficacy on the melanoma PDOX. Melanoma PDOX nude mice were randomized into four groups of 5 mice each: untreated control; ip-rMETase (100 units, i.p., 14 consecutive days); o-rMETase (100 units, p.o., 14 consecutive days); o-rMETase+ip-rMETase (100 units, p.o.+100 units, i.p., 14 consecutive days). All treatments inhibited tumor growth on day 14 after treatment initiation, compared to untreated control (ip-rMETase, p<0.0001; o-rMETase, p<0.0001; o-rMETase+ip-rMETase, p<0.0001). o-rMETase was significantly more effective than ip-rMETase (p = 0.0086). o-rMETase+ip-rMETase was significantly more effective than either mono-therapy: ip-rMETase, p = 0.0005; or o-rMETase, p = 0.0367. The present study is the first demonstrating that o-rMETase is effective as an anticancer agent. The results of the present study indicate the potential of clinical development of o-rMETase as an agent for chronic cancer therapy and for cancer prevention and possibly for life extension since dietary MET reduction extends life span in many animal models.

In the present study, a patient-derived orthotopic xenograft (PDOX) model of recurrent cisplatinum (CDDP)-resistant metastatic osteosarcoma was treated with Salmonella typhimurium A1-R (S. typhimurium A1-R), which decoys chemoresistant quiescent cancer cells to cycle, and recombinant methioninase (rMETase), which selectively traps cancer cells in late S/G 2 , and chemotherapy. The PDOX models were randomized into the following groups 14 days after implantation: G1, control without treatment; G2, CDDP (6 mg/kg, intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, rMETase (100 unit/mouse, i.p., daily, for 2 weeks). G4, S. typhimurium A1-R (5 × 10 7 CFU/100 μl, i.v., weekly, for 2 weeks); G5, S. typhimurium A1-R (5 × 10 7 CFU/100 μl, i.v., weekly, for 2 weeks) combined with rMETase (100 unit/mouse, i.p., daily, for 2 weeks); G6, S. typhimurium A1-R (5 × 10 7 CFU/100 μl, i.v., weekly, for 2 weeks) combined with rMETase (100 unit/mouse, i.p., daily, for 2 weeks) and CDDP (6 mg/kg, i.p. injection, weekly, for 2 weeks). On day 14 after initiation, all treatments except CDDP alone, significantly inhibited tumor growth compared to untreated control: (CDDP: p = 0.586; rMETase: p = 0.002; S. typhimurium A1-R: p = 0.002; S. typhimurium A1-R combined with rMETase: p = 0.0004; rMETase combined with both S. typhimurium A1-R and CDDP: p = 0.0001). The decoy, trap and kill combination of S. typhimurium A1-R, rMETase and CDDP was the most effective of all therapies and was able to eradicate the metastatic osteosarcoma PDOX.

A patient-derived orthotopic xenograft (PDOX) model of undifferentiated pleomorphic sarcoma (UPS) was previously established that acquired red fluorescent protein (RFP)-expressing stroma by growth in an RFP transgenic nude mouse. In the present study, an imageable PDOX model (iPDOX) of UPS was established by orthotopic implantation in the biceps femoris of transgenic RFP nude mice. After the tumors grew to a diameter of 10 mm, they were harvested and the brightest portion of the tumors were subsequently orthotopically transplanted to both RFP and non-colored nude mice. The UPS PDOX tumor was again transplanted to RFP transgenic and non-colored nude mice, and finally a 3rd passage was made in the same manner. Five UPS tumors from each passage in both RFP and non-colored mouse models were harvested. The FV1,000 confocal microscope was used to visualize and quantitate the RFP area of the resected tumors. The average percent fluorescent area in the first passage of RFP mice was 34 ± 22%; in the second passage, 34 ± 20%; and 36 ± 11% in the third passage of RFP transgenic nude mice. The average tumor RFP area in the first passage from RFP mice to non-colored mice was 20 ± 7%; in the second passage, 28 ± 11%; in the third passage was 27 ± 13%. The present results demonstrate the extensive and stable acquisition of stroma by the UPS-tumor growing orthotopically in transgenic RFP nude mice (iPDOX). This model can be used for screening for effective drugs for individual patients and drug discovery. J. Cell. Biochem. 118: 3367-3371, 2017. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

The aim of the present study was to determine the usefulness of a patient-derived orthotopic xenograft (PDOX) nude-mouse model of a doxorubicin-resistant metastatic Ewing's sarcoma, with a unique combination of a FUS-ERG fusion and CDKN2A deletion, to identify effective drugs for third-line chemotherapy of the patient. Our previous study showed that cyclin-dependent kinase 4/6 (CDK4/6) and insulin-like growth factor-1 receptor (IGF-1R) inhibitors were effective on the Ewing's sarcoma PDOX, but not doxorubicin, similar to the patient's resistance to doxorubicin. The results of the previous PDOX study were successfully used for second-line therapy of the patiend. In the present study, the PDOX mice established with the Ewing's sarcoma in the right chest wall were randomized into 5 groups when the tumor volume reached 60 mm 3 : untreated control; gemcitabine combined with docetaxel (intraperitoneal [i.p.] injection, weekly, for 2 weeks); irinotecan combined with temozolomide (irinotecan: i.p. injection; temozolomide: oral administration, daily, for 2 weeks); pazopanib (oral administration, daily, for 2 weeks); yondelis (intravenous injection, weekly, for 2 weeks). All mice were sacrificed on day 15. Body weight and tumor volume were assessed 2 times per week. Tumor weight was measured after sacrifice. Irinotecan combined with temozolomide was the most effective regimen compared to the untreated control group (p=0.022). Gemcitabine combined with docetaxel was also effective (p=0.026). Pazopanib and yondelis did not have significant efficacy compared to the untreated control (p=0.130, p=0.818). These results could be obtained within two months after the physician's request and were used for third-line therapy of the patient., Competing Interests: CONFLICTS OF INTEREST K.M., T.M., T.K., K.I., K.K. M.M., and R.M.H. are unsalaried associates of AntiCancer Inc. There are no other competing financial interests.

Background: Methionine dependence may be the only known general metabolic defect in cancer. In order to exploit methionine dependence for therapy, our laboratory previously cloned L-methionine α-deamino-γ-mercaptomethane lyase [EC 4.4.1.11]) (recombinant methioninase [rMETase]), which was subsequently tested in mouse models of various types of human tumors. The present study aimed to investigate the efficacy of rMETase on human osteosarcoma cells in vitro and in vivo., Materials and Methods: Human osteosarcoma cell lines 143B, HOS and SOSN2 were tested in vitro for survival during a 72-h exposure to rMETase using the WST-8 assay. Half-maximal inhibitory concentrations were calculated for in vitro efficacy experiments. 143B cells were orthotopically transplanted into the tibia of nude mice. Mouse models were randomized into the following groups 1 week after transplantation: Group 1, untreated control; Group 2, cisplatinum (CDDP) [intraperitoneal (i.p.) injection at 6 mg/kg weekly, for 3 weeks], positive control; Group 3, rMETase, 100 units/mouse i.p. daily, for 21 days. Tumor sizes and body weight were measured with calipers and a digital balance once per week, respectively., Results: rMETase significantly inhibited osteosarcoma cell growth, in a dose-dependent manner, in vitro. Both CDDP and rMETase treatment significantly inhibited tumor volume compared to untreated control mice at 5 weeks after initiation. Tumor volumes were as follows: Group 1, untreated, control: 1808.2 ± 344 mm 3 ; Group 2, CDDP: 1102.2 ± 316 mm 3 , p=0.0008 compared to untreated control; Group 3, rMETase: 884.8 ± 361 mm 3 , p=0.0001 compared to untreated control. There were no animal deaths in any group. The body weight of mice was not significantly different between any group., Conclusion: rMETase showed promising efficacy against osteosarcoma, a recalcitrant tumor type. Future studies will investigate the efficacy of rMETase on patient-derived orthotopic xenograft (PDOX) models of osteosarcoma as a bridge to testing rMETase in the clinic., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

An excessive requirement for methionine termed methionine dependence, appears to be a general metabolic defect in cancer. We have previously shown that cancer-cell growth can be selectively arrested by methionine deprivation such as with recombinant methioninase (rMETase). The present study used a previously-established patient-derived orthotopic xenograft (PDOX) nude mouse model of BRAF V600E-mutant melanoma to determine the efficacy of rMETase in combination with a first-line melanoma drug, temozolomide (TEM). In the present study 40 melanoma PDOX mouse models were randomized into four groups of 10 mice each: untreated control (n=10); TEM (25 mg/kg, oral 14 consecutive days, n=10); rMETase (100 units, intraperitoneal 14 consecutive days, n=10); combination TEM + rMETase (TEM: 25 mg/kg, oral rMETase: 100 units, intraperitoneal 14 consecutive days, n=10). All treatments inhibited tumor growth compared to untreated control (TEM: p =0.0081, rMETase: p =0.0037, TEM-rMETase: p =0.0024) on day 14 after initiation. However, the combination therapy of TEM and rMETase was significantly more efficacious than either mono-therapy (TEM: p =0.0051, rMETase: p =0.0051). The present study is the first demonstrating the efficacy of rMETase combination therapy in a PDOX model, suggesting potential clinical development, especially in recalcitrant cancers such as melanoma, where rMETase may enhance first-line therapy., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.

Background/aim: We have previously reported that caffeine (CAF) can enhance chemotherapy efficacy of bone and soft-tissue sarcoma established cell lines via cell-cycle perturbation. We subsequently tested the combination of valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, with caffeine on established human osteosarcoma cells in vitro. Both VPA and CAF caused concentration-dependent cell death of the osteosarcoma cell lines in vitro, and their combination was synergistic. We subsequently established patient-derived cell lines from undifferentiated pleomorphic sarcoma (UPS) and rhabdomyosarcoma (RMS), both of which are recalcitrant cancers. These cell lines are termed AC-UPS01 and AC-RMS01, respectively., Materials and Methods: In the present study, we tested CAF and VPA and their combination on the two patient-derived sarcoma cell lines. Cell survival after a 72 h exposure to each drug was determined by the WST-8 assay. IC 50 values were calculated for each drug., Results: CAF and VPA caused concentration-dependent cytocidal efficacy for both cell lines. The IC 50 for CAF for AC-UPS01 was 2.02 ± 0.22 mM. The IC 50 for VPA for AC-UPS01 was 9.54 ± 1.44 mM. The IC 50 for CAF for AC-RMS01 was 2.37 ± 0.48 mM. The IC 50 for VPA for AC-RMS01 was 2.13 ± 0.20 mM. Synergistic efficacy of combination treatment of CAF and VPA was also observed for both cell lines., Conclusion: The results of the present study suggest that CAF and VPA may be useful in the treatment of recalcitrant sarcoma., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

A pancreatic ductal adenocarcinoma (PDAC), obtained from a patient, was grown orthotopically in the pancreatic tail of nude mice to establish a patient-derived orthotopic (PDOX) model. Seven weeks after implantation, PDOX nude mice were divided into the following groups: untreated control (n = 7); gemcitabine (100 mg/kg, i.p., once a week for 2 weeks, n = 7); cobimetinib (5 mg/kg, p.o., 14 consecutive days, n = 7); trametinib (0.3 mg/kg, p.o., 14 consecutive days, n = 7); trabectedin (0.15 mg/kg, i.v., once a week for 2 weeks, n = 7); temozolomide (25 mg/kg, p.o., 14 consecutive days, n = 7); carfilzomib (2 mg/kg, i.v., twice a week for 2 weeks, n = 7); bortezomib (1 mg/kg, i.v., twice a week for 2 weeks, n = 7); MK-1775 (20 mg/kg, p.o., 14 consecutive days, n = 7); BEZ-235 (45 mg/kg, p.o., 14 consecutive days, n = 7); vorinostat (50 mg/kg, i.p., 14 consecutive days, n = 7). Only the MEK inhibitors, cobimetinib and trametinib, regressed tumor growth, and they were more significantly effective than other therapies (p < 0.0001, respectively), thereby demonstrating the precision of the PDOX models of PDAC and its potential for individualizing pancreatic-cancer therapy.

In the present study, we evaluated the efficacy of trabectedin (TRAB) and temozolomide (TEM) compared to cisplatinum (CDDP) on a patient-derived orthotopic xenogrraft (PDOX) of a lung-metastasis from an osteosarcoma of a patient who failed CDDP therapy. Osteosarcoma resected from the patient was implanted orthotopically in the distal femur of mice to establish PDOX models which were randomized into the following groups when tumor volume reached approximately 100 mm 3 : G1, control without treatment; G2, CDDP (6 mg/kg, intraperitoneal injection, weekly, for 2 weeks); G3, TRAB (0.15 mg/kg, intravenous injection, weekly, for 2 weeks); G4, TEM (25 mg/kg, oral, daily, for 14 days). Tumor size and body weight were measured with calipers and a digital balance, respectively, twice a week. On day 14 after initiation of treatment, TEM and TRAB, but not CDDP, significantly inhibited tumor volume compared to untreated control: control (G1): 814.5±258.8 mm 3 ; CDDP (G2): 608.6±126.9 mm 3 ; TRAB (G3): 286.6±133.0 mm 3 ; TEM (G4): 182.9±69.1 mm 3 . CDDP vs. control, p=0.07; TRAB vs. control, p=0.0004; TEM vs. control p =0.0002; TRAB vs. CDDP, p =0.0002; TEM vs. CDDP, p =0.00003. The results of the present study show that a PDOX model of an osteosarcoma lung-metastasis that recurred after adjuvant CDDP-treatment has identified potentially, highly-effective drugs for this recalcitrant disease, while accurately maintaining the CDDP resistance of the tumor in the patient, thereby demonstrating the potential of the osteosarcoma PDOX model for precision oncology., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.

A metastatic melanoma obtained from the right chest wall of a patient was previously established orthotopically in the right chest wall of nude mice as a patient-derived orthotopic xenograft (PDOX) model. We previously showed that the combination of tumor-targeting Salmonella typhimurium A1-R (S. typhimurium A1-R) and chemotherapy was highly effective against the melanoma PDOX. In the present study, we investigated the mechanism of the high efficacy of this combination. Two weeks after implantation, 40 PDOX mouse models were randomized into 4 groups of 10 mice each: untreated control (n = 10); treated with S. typhimurium A1-R (5 × 10 7 CFU/100 μl, i.v., once a week for 2 weeks, n = 10); treated with temozolomide (TEM) (25 mg/kg, p.o. for 14 consecutive days) combined with S. typhimurium A1-R (5 × 10 7 CFU/100 μl, i.v., once a week for 2 weeks, n = 10); treated with vemurafenib (VEM) (30 mg/kg, p.o., for 14 consecutive days) combined with S. typhimurium A1-R (5 × 10 7 CFU/100 μl, i.v., once a week for 2 weeks) (n = 10). On day 14 from initiation, all treatments significantly inhibited tumor growth compared with untreated control (S. typhimurium A1-R: p < 0.01; TEM combined with S. typhimurium A1-R: p < 0.01; VEM combined with S. typhimurium A1-R: p < 0.01). Combination therapy with S. typhimurium A1-R was significantly more effective on tumor growth than S. typhimurium A1-R alone (with TEM: p < 0.01; with VEM: p < 0.01). Combination therapy significantly increased S. typhimurium A1-R tumor targeting alone (S. typhimurium A1-R + TEM: p < 0.01, S. typhimurium A1-R + VEM: p < 0.01), relative to S. typhimurium A1-R alone, respectively. In conclusion, chemotherapy drugs promoted targeting of S. typhimurium A1-R of melanoma, thereby enhancing efficacy against the melanoma PDOX.

A patient high-grade undifferentiated pleomorphic soft-tissue sarcoma (UPS) from a striated muscle was previously orthotopically implanted in the right biceps femoris muscle of nude mice to establish a patient-derived orthotopic xenograft (PDOX) nude-mouse model. In the present study, two weeks after orthotopic transplantation of the UPS, mice were treated intraperitoneally with cisplatinum (CDDP), doxorubicin (DOX) or a novel anionic-phosphate-platinum compound 3Pt. Treatments were repeated weekly for a total of 3 times. Six weeks after transplantation, all mice were sacrificed and evaluated. After two weeks treatment, tumor sizes were as follows: control (G1): 2208.3 mm 3 ; CDDP (G2): 841.8±3 mm 3 , p=0.0001; DOX (G3): 693.1±3 mm 3 , p=6.56E-7; 3Pt (G4): 333.7±1 mm 3 , p=4.8E-8. 3Pt showed significantly more efficacy compared to other therapy drugs tested: CDDP (p=0.0002), DOX (p=0.001). There were no animal deaths in any of the four groups. The present results suggest 3Pt is a promising new candidate for UPS since it was demonstrated to be effective in a PDOX model., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.

Previously, a patient-derived orthotopic xenograft (PDOX) model was established with a lung metastasis from an osteosarcoma patient which developed after adjuvant cisplatinum (CDDP) treatment. In this model, we previously demonstrated the efficacy of trabectedin (TRAB) and temozolomide (TEM) compared with CDDP. In the present report, osteosarcoma tissue was implanted orthotopically in the distal femur of mice which were randomized into the following groups when tumor volume reached approximately 100 mm 3 ; On day 14 after initiation of treatment, all but CDDP significantly inhibited tumor volume growth compared with untreated controls. Control (G1): 793.7 ± 215.0 mm 3 ; CDDP (G2): 588.1 ± 176.9 mm 3 ; Salmonella typhimurium A1-R (S. typhimurium A1-R) intravenous (i.v.) (G3): 269.7 ± 72.7 mm 3 ; S. typhimurium A1-R intra-arterial (i.a.) (G4): 70.2 ± 18.9 mm 3 (CDDP: p = 0.056; S. typhimurium A1-R i.v.: p = 0.0001; S. typhimurium A1-R i.a.: p = 0.00003, all vs. untreated controls). i.a. administration of S. typhimurium A1-R was significantly more effective than either CDDP (p = 0.00007), or i.v. administration of S. typhimurium A1-R (p = 0.00007) and significantly regressed the tumor volume compared with day 0 (p = 0.001). The new model of i.a. administration of S. typhimurium A1-R has great promise for the treatment of recalcitrant osteosarcoma.

Gastric leiomyosarcoma is a recalcitrant cancer and the chemotherapy strategy is controversial. The present study used a patient-derived orthotopic xenograft (PDOX) nude mouse model of gastric leiomyosarcoma to identify an effective therapeutic regimen to develop individualized precision medicine for this disease. The gastric leiomyosarcoma obtained from a patient was first grown in transgenic nude mice ubiquitously expressing red fluorescent protein (RFP) to stably label the tumor stroma. The RFP-expressing tumor was then passaged orthotopically in the gastric wall of non-transgenic nude mice to establish an imageable PDOX (iPDOX) model. The bright fluorescent tumor was readily imaged over time to determine drug efficacy. Four weeks after implantation, 70 PDOX nude mice were divided into 7 groups: control without treatment (n = 10); doxorubicin (DOX) (2.4 mg/kg, intraperitoneally (i.p.), once a week for 2 weeks, n = 10); gemcitabine (GEM)/ docetaxel (DOC) (GEM: 100 mg/kg, DOC: 20 mg/kg, i.p., once a week for 2 weeks, n = 10); cyclophosphamide (CPA) (140 mg/kg, i.p., once a week for 2 weeks, n = 10); temozolomide (TEM) (25 mg/kg, orally, daily for 14 consecutive days, n = 10); yondelis (YON) (0.15 mg/kg, i.v., once a week for 2 weeks, n = 10); pazopanib (PAZ) (100 mg/kg, orally, daily for 14 consecutive days, n = 10). On day 14 from initiation of treatment, all treatments except PAZ significantly inhibited tumor growth compared with untreated control (DOX: p < 0.01, GEM/DOC: p < 0.01, CPA: p < 0.01, TEM: p < 0.01, YON: p < 0.01) on day 14 after initiation. In addition, only GEM/DOC was more significantly effective than DOX (p < 0.05). GEM/DOC could regress the leimyosarcoma in the PDOX model and has important clinical potential for precision individual treatment of leiomyosarcoma patients.

Methionine dependence is due to the overuse of methionine for aberrant transmethylation reactions in cancer. Methionine dependence may be the only general metabolic defect in cancer. In order to exploit methionine dependence for therapy, our laboratory previously cloned L-methionine α-deamino-γ-mercaptomethane lyase [EC 4.4.1.11]). The cloned methioninase, termed recombinant methioninase, or rMETase, has been tested in mouse models of human cancer cell lines. Ewing's sarcoma is recalcitrant disease even though development of multimodal therapy has improved patients'outcome. Here we report efficacy of rMETase against Ewing's sarcoma in a patient-derived orthotopic xenograft (PDOX) model. The Ewing's sarcoma was implanted in the right chest wall of nude mice to establish a PDOX model. Eight Ewing's sarcoma PDOX mice were randomized into untreated control group (n = 4) and rMETase treatment group (n = 4). rMETase (100 units) was injected intraperitoneally (i.p.) every 24 hours for 14 consecutive days. All mice were sacrificed on day-15, 24 hours after the last rMETase administration. rMETase effectively reduced tumor growth compared to untreated control. The methionine level both of plasma and supernatants derived from sonicated tumors was lower in the rMETase group. Body weight did not significantly differ at any time points between the 2 groups. The present study is the first demonstrating rMETase efficacy in a PDOX model, suggesting potential clinical development, especially in recalcitrant cancers such as Ewing's sarcoma.

Adult pleomorphic rhabdomyosarcoma (RMS) is a rare and recalcitrant, highly-malignant mesenchymal tumor in need of improved therapeutic strategies. Our laboratory pioneered the patient-derived orthotopic xenograft (PDOX) nude mouse model with the technique of surgical orthotopic implantation (SOI). We previously described the development of a PDOX model of adult pleomorphic RMS where the tumor behaved similar to the patient donor. A high-grade pleomorphic rhabdomyosarcoma from a striated muscle was previously grown orthotopically in the right biceps-femoris muscle of nude mice to establish the PDOX model. In the present study, the PDOX models were randomized into the following treatment groups when tumor volume reached 100 mm 3 : G1, control without treatment; G2, cyclophosphamide (CPA) 140 mg/kg, intraperitoneal (i.p.) injection, weekly, for 3 weeks; G3, temozolomide (TEM), 25 mg/kg, per oral (p.o.), daily, for 21 days; G4, temozolomide (TEM) 25 mg/kg, p.o., daily, for 21 days combined with irinotecan (IRN), 4 mg/kg, i.p., daily for 21 days. After 3 weeks, treatment of PDOX with TEM combined with IRN was so powerful that it resulted in tumor regression and the smallest tumor volume compared to other groups. The RMS PDOX model should be of use to design the treatment program for the patient and for drug discovery and evaluation for this recalcitrant tumor type., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflicts of interest.

Liver metastasis is the main cause of colon cancer-related death and is a recalcitrant disease. We report here the efficacy and safety of intra-portal-vein (iPV) targeting of Salmonella typhimurium A1-R on colon cancer liver metastasis in a nude-mouse orthotopic model. Nude mice with HT29 human colon cancer cells, expressing red fluorescent protein (RFP) (HT29-RFP), growing in the liver were administered S. typhimurium A1-R by either iPV (1×104 colony forming units (CFU)/100 μl) or, for comparison, intra-venous injection (iv; 5×107 CFU/100 μl). Similar amounts of bacteria were delivered to the liver with the two doses, indicating that iPV delivery is 5×103 times more efficient than iv delivery. Treatment efficacy was evaluated by tumor fluorescent area (mm2) and total fluorescence intensity. Tumor fluorescent area and fluorescence intensity highly correlated (p<0.0001). iPV treatment was more effective compared to both untreated control and iv treatment (p<0.01 and p<0.05, respectively with iPV treatment with S. typhimurium arresting metastatic growth). There were no significant differences in body weight between all groups. The results of this study suggest that S. typhimurium A1-R administered iPV has potential for peri-operative adjuvant treatment of colon cancer liver metastasis.

Aim: We have previously reported that caffeine can enhance chemotherapy efficacy of bone and soft tissue sarcoma via cell-cycle perturbation. Valproic acid has histone deacetylase (HDAC) inhibitory activity. We have also reported the anti-tumor efficacy of combination treatment with caffeine and valproic acid against osteosarcoma primary tumors in a cell-line orthotopic mouse model., Materials and Methods: In this study, we performed combination treatment of caffeine and valproic acid on osteosarcoma cell lines in vitro and in spontaneous and experimental lung metastasis mouse models of osteosarcoma. Survival of 143B-RFP human osteosarcoma cells after exposure to caffeine and valproic acid for 72 hours was determined using the WST-8 assay. IC 50 values and combination indices were calculated. Mouse models of primary osteosarcoma and spontaneous lung metastasis were obtained by orthotopic intra-tibial injection of 143B-RFP cells. Valproic acid, caffeine, and combination of both drugs were administered from day 7, five times a week, for four weeks. Six weeks after orthotopic injection, lung samples were excised and observed with a fluorescence imaging system. A mouse model of experimental lung metastasis was obtained by tail vein injection of 143B-RFP cells. The mice were treated with these agents from day 0, five times a week for four weeks., Results: Both caffeine and valproic acid caused concentration-dependent cell kill in vitro. Synergistic efficacy of the combination treatment was observed. In the spontaneous lung-metastasis model, the number of lung metastasis was 9.0±2.6 in the untreated group (G1); 10.8±2.9 in the caffeine group (G2); 10.0±3.1 in the valproic-acid group (G3); and 3.0±1.1 in the combination group (G4); (p=6.78E-5 control vs. combination; p=0.006 valproic acid vs. combination; p=0.003 caffeine vs. combination). In the experimental lung-metastasis model, the combination group significantly reduced lung metastases and improved overall survival (p=0.0005)., Conclusion: Efficacy of the combination of caffeine and valproic acid was observed in vitro and in spontaneous and experimental lung-metastasis mouse models of osteosarcoma., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Our laboratory pioneered patient-derived orthotopic xenograft (PDOX) mouse models using surgical orthotopic implantation (SOI). PDOX models are patient-like, in contrast to the ectopic subcutaneous-transplant cancer models. In the present study, we demonstrate that an undifferentiated pleomorphic soft-tissue sarcoma (UPS-STS) PDOX model acquired bright RFP-expressing stroma through one passage in red fluorescent protein (RFP) transgenic mice, which upon passage to non-colored nude mice was non-invasively imageable. A PDOX nude mouse model of UPS-STS was established in the biceps femoris of nude mice. After the tumors grew to a diameter of 10 mm, the tumors were subsequently passaged to RFP transgenic mice, and after tumor growth were then passaged to non-transgenic nude mice. Tumors were divided into small fragments and transplanted in the biceps femoris at each passage. The OV100 Small Animal Fluorescence Imaging System and FV1000 laser scanning confocal microscope were used to image RFP fluorescence in the UPS-STS PDOX models. UPS-STS PDOX tumors, previously grown in RFP transgenic nude mice for only one passage, had very bright fluorescence and after passage to non-transgenic nude mice maintained the bright fluorescence and were non-invasively imageable. FV1000 confocal imaging revealed diffusely distributed bright RFP stromal cells in the PDOX tumor, both in RFP transgenic mice and after passage to non-transgenic mice. These results demonstrate a powerful method to make the PDOX UPS-STS model brightly fluorescent for non-invasive imaging, as well as for confocal microscopy of individual stromal cells associated with the tumor. The RFP-labeled UPS PDOX has the potential to rapidly screen for novel effective agents for individual patients, including stroma-targeting drugs, whereby the stromal cells are a visual target. J. Cell. Biochem. 118: 361-365, 2017. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Osteosarcoma occurs mostly in children and young adults, who are treated with multiple agents in combination with limb-salvage surgery. However, the overall 5-year survival rate for patients with recurrent or metastatic osteosarcoma is 20-30% which has not improved significantly over 30 years. Refractory patients would benefit from precise individualized therapy. We report here that a patient-derived osteosarcoma growing in a subcutaneous nude-mouse model was regressed by tumor-targeting Salmonella typhimurium A1-R (S. typhimurium A1-R, p<0.001 compared to untreated control). The osteosarcoma was only partially sensitive to the molecular-targeting drug sorafenib, which did not arrest its growth. S. typhimurium A1-R was significantly more effective than sorafenib (P <0.001). S. typhimurium grew in the treated tumors and caused extensive necrosis of the tumor tissue. These data show that S. typhimurium A1-R is powerful therapy for an osteosarcoma patient-derived xenograft model.

Rhabdomyosarcoma (RMS) is a rare mesenchymal tumor. The aim of the present study was to develop a patient-derived orthotopic xenograft (PDOX) mouse model of RMS and compare the PDOX model to a subcutaneous (s.c.)-transplant model. A patient RMS from a striated muscle was grown orthotopically in the right biceps femoris muscle and right quadriceps muscle of nude mice to establish a PDOX model, as well as under the skin to establish an s.c., Model: PDOX tumors grew at a statistically-significant faster rate compared to the s.c. tumors. Recurrence after surgical resection occurred only in PDOX tumors, not in the s.c., Model: Histologically, only the PDOX model was shown to be invasive. In conclusion, these results indicate that the PDOX model of adult RMS is malignant and the subcutaneous model is benign. These results emphasize that a proper tumor microenvironment is necessary for patient-like behavior of a tumor in a mouse model.

Background: Cervical cancer is a world-wide problem that requires transformative therapeutic strategies. We have previously developed patient-derived orthotopic xenograft (PDOX) nude-mouse models of this disease. In the present report, we demonstrate that the standard drug, cisplatinum (CDDP), is highly-effective while the new, highly-touted agent, nab-paclitaxel (NAB-PTX) is ineffective., Materials and Methods: Cervical PDOX tumors were grown on the cervix of nude mice for 4 weeks after surgical orthotopic implantation (SOI). Tumors were treated with CDDP or NAB-PTX., Results: H&E staining demonstrated that the PDOX tumor recapitulated the original patient tumor. CDDP was highly-effective. One tumor that was treated with CDDP completely regressed. CDDP-treated tumors were smaller (tumor volume ratio: 0.42±0.36) than the control group (tumor volume ratio: 3.47±1.66) (p<0.01). In contrast, NAB-PTX did not show significant efficacy on the cervical cancer PDOX model (tumor volume ratio: 2.85±1.45) (p=0.47). CDDP-treated tumor weight (50±50 mg) was significantly less than control (238±114 mg) (p<0.01). NAB-PTX-treated tumors were not reduced in weight (246±136 mg) compared to control (p=0.91). There were no significant differences in mouse body weight between groups. Histological evaluation demonstrated that CDDP-treated tumors were fibrotic with scattered squamous cell nests compared to control or NAB-PTX-treated tumors., Conclusion: The results of the present study demonstrate the power of PDOX models of cervical cancer to distinguish efficacy of potential therapeutics for individual patients with this disease., (Copyright© 2017 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Melanoma is a recalcitrant disease in need of transformative therapuetics. The present study used a patient-derived orthotopic xenograft (PDOX) nude-mouse model of melanoma with a BRAF-V600E mutation to determine the efficacy of temozolomide (TEM) combined with tumor-targeting Salmonella typhimurium A1-R. A melanoma obtained from the right chest wall of a patient was grown orthotopically in the right chest wall of nude mice to establish a PDOX model. Two weeks after implantation, 40 PDOX nude mice were divided into 4 groups: G1, control without treatment (n = 10); G2, TEM (25 mg/kg, administrated orally daily for 14 consecutive days, n = 10); G3, S. typhimurium A1-R (5 × 107 CFU/100 μl, i.v., once a week for 2 weeks, n = 10); G4, TEM combined with S. typhimurium A1-R (25 mg/kg, administrated orally daily for 14 consecutive days and 5 × 107 CFU/100 μl, i.v., once a week for 2 weeks, respectively, n = 10). Tumor sizes were measured with calipers twice a week. On day 14 from initiation of treatment, all treatments significantly inhibited tumor growth compared to untreated control (TEM: p < 0.0001; S. typhimurium A1-R: p < 0.0001; TEM combined with S. typhimurium A1-R: p < 0.0001). TEM combined with S. typhimurium A1-R was significantly more effective than either S. typhimurium A1-R (p = 0.0004) alone or TEM alone (p = 0.0017). TEM combined with S. typhimurium A1-R could regress the melanoma in the PDOX model and has important future clinical potential for melanoma patients.

Melanoma is a recalcitrant disease. The present study used a patient-derived orthotopic xenograft (PDOX) model of melanoma to test sensitivity to three molecularly-targeted drugs and one standard chemotherapeutic. A BRAF-V600E-mutant melanoma obtained from the right chest wall of a patient was grown orthotopically in the right chest wall of nude mice to establish a PDOX model. Two weeks after implantation, 50 PDOX nude mice were divided into 5 groups: G1, control without treatment; G2, vemurafenib (VEM) (30 mg/kg); G3; temozolomide (TEM) (25 mg/kg); G4, trametinib (TRA) (0.3 mg/kg); and G5, cobimetinib (COB) (5 mg/kg). Each drug was administered orally, daily for 14 consecutive days. Tumor sizes were measured with calipers twice a week. On day 14 from initiation of treatment, TRA, an MEK inhibitor, was the only agent of the 4 tested that caused tumor regression (P < 0.001 at day 14). In contrast, another MEK inhibitor, COB, could slow but not arrest growth or cause regression of the melanoma. First-line therapy TEM could slow but not arrest tumor growth or cause regression. The patient in this study had a BRAF-V600E-mutant melanoma and would be considered to be a strong candidate for VEM as first-line therapy, since VEM targets this mutation. However, VEM was not effective. The PDOX model thus helped identify the very-high efficacy of TRA against the melanoma PDOX and is a promising drug for this patient. These results demonstrate the powerful precision of the PDOX model for cancer therapy, not achievable by genomic analysis alone.

Ewing's sarcoma is a rare and aggressive malignancy. In the present study, tumor from a patient with a Ewing's sarcoma with cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) loss and FUS-ERG fusion was implanted in the right chest wall of nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. The aim of the present study was to determine efficacy of cyclin-dependent kinase 4/6 (CDK4/6) and insulin-like growth factor-1 receptor (IGF-1R) inhibitors on the Ewing's sarcoma PDOX. The PDOX models were randomized into the following groups when tumor volume reached 50 mm3: G1, untreated control; G2, doxorubicin (DOX) (intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, CDK4/6 inhibitor (palbociclib, PD0332991, per oral (p.o.), daily, for 14 days); G4, IGF-1R inhibitor (linsitinib, OSI-906, p.o., daily, for 14 days). Tumor growth was significantly suppressed both in G3 (palbociclib) and in G4 (linsitinib) compared to G1 (untreated control) at all measured time points. In contrast, DOX did not inhibit tumor growth at any time point, which is consistent with the failure of DOX to control tumor growth in the patient. The results of the present study demonstrate the power of the PDOX model to identify effective targeted molecular therapy of a recalcitrant DOX-resistant Ewing's sarcoma with specific genetic alterations. The results of this study suggest the potential of PDOX models for individually-tailored, effective targeted therapy for recalcitrant cancer., Competing Interests: Y.Z. is an employee of AntiCancer Inc. T.M., T.K., K.I., K.K. and R.M.H. are unsalaried associates of AntiCancer Inc. R.M.H. is an unsalaried associate of PDOX Inc. There are no other competing financial interests.

Follicular dendritic-cell sarcoma (FDCS) is a rare and recalcitrant disease. In the present study, a patient-derived orthotopic xenograft (PDOX) mouse model of FDCS was established in the biceps muscle of nude mice. The FDCS PDOX was resistant to both doxorubicin (DOX) and NVP-BEZ235, dactolisib (BEZ) an experimental agent which is a dual pan-phosphoinositide 3-kinase-mammalian target of rapamycin inhibitor. However, in contrast to DOX and BEZ, the FDCS PDOX was sensitive to the tumor-targeting bacterial strain, Salmonella typhimurium A1-R (S. typhimurium A1-R). The combination of S. typhimurium A1-R and either DOX or BEZ did not increase the antitumor efficacy of S. typhimurium A1-R, indicating that DOX and BEZ were not active in this PDOX model. The efficacy of S. typhimurium A1-R in this recalcitrant FDCS gives strong impetus to move bacterial therapy to clinical trials for this disease. The findings of the present study are of particular importance since it demonstrates that S. typhimurium A1-R is effective in a PDOX model of FDCS established from a patient who failed DOX therapy., Competing Interests: Y.Z. and M.Z. are employees of AntiCancer Inc. T.K., T.M., K.K., K.I. and R.M.H. are unsalaried associates of AntiCancer Inc. R.M.H. is an unsalaried associate of PDOX LLC. There are no other competing financial interests.

Here we report a rare case of late recurrence of pancreatic cancer 8 years after surgery. A woman in her mid-fifties was hospitalized for examination of epigastralgia. Computed tomography (CT) revealed a 4 cm nodule at the pancreatic head with suspected invasion of the superior mesenteric vein. She underwent pancreaticoduodenectomy with wedge resection of superior mesenteric vein and intraoperative radiation therapy. Pathological findings showed moderately differentiated tubular adenocarcinoma and T3N1M0, Stage IIB according to The Union for International Cancer Control (UICC) TNM classification. As adjuvant chemotherapy, 56 courses of gemcitabine (GEM) were administered in 3.5 years. Because of long-term use of GEM, common terminology criteria for adverse events (CTCAE) Grade 3 anemia occurred, and chemotherapy was discontinued. Tumor markers were evaluated every month and CT scans were taken every 6 months for 5 years. Subsequently, CT was performed annually. The patient was hospitalized for high-grade fever, 8.5 years after surgery. CT, magnetic resonance imaging (MRI) and positron emission tomography-computed tomography (PET-CT) detected local recurrence with liver metastases. GEM was administered again, but was ineffective. The patient died 9 years after surgery. In conclusion, even if long-term survival is achieved in pancreatic cancer, follow-ups should not be stopped.

A man in his 40s had a locally advanced pancreatic head cancer invading the portal vein( PV) and common hepatic artery (CHA). He underwent 5 courses of neoadjuvant chemotherapy( gemcitabine+S-1), which reduced the tumor volume and cancer antigen 19-9 (CA19-9) level. R0 resection was performed via sub-stomach preserving pancreatoduodenectomy with combined resection of the PV and CHA. Adjuvant chemotherapy with gemcitabine was administered at 4 weeks after the operation. Relevant neoadjuvant chemotherapy is considered to contribute to R0 resection of locally advanced pancreatic cancer. Here, we report a case of a successful R0 resection after neoadjuvant chemotherapy for locally advanced pancreatic cancer.

Surgery followed by adjuvant chemotherapy is standard care for resectable pancreatic carcinoma. The maximum estimated 2-year survival rate associated with this strategy is nearly 50%. The use of neoadjuvant therapy for pancreatic cancer remains controversial, and its efficacy has not been elucidated. To evaluate the efficacy of neoadjuvant chemotherapy for planned pancreatic cancer resection, the oncological outcomes of neoadjuvant gemcitabine plus S-1 combination therapy( GS therapy) and a surgery-first approach were retrospectively compared. Patients with planned pancreatic cancer resection and without major artery abutments were enrolled in this study. There were 39 cases of neoadjuvant GS therapy (N group) and 93 cases of the surgery-first approach( S group). Survival and surrogate markers, including the R0 rate, the "true R0 rate"( R0 with tumor marker normalization after resection), and N0 rate, were compared. The groups did not differ significantly in terms of age, gender, or tumor location. The resection rates of the N and S groups were similar (92% and 86%, respectively). The median survival of the N group (39.4 months) was significantly longer than that of the S group (20.8 months) in intention-to-treat analysis (p=0.0009). The R0, true R0, and N0 rates of the N group (85%, 69%, and 44%, respectively) were higher than those of the S group( 72%, 48%, and 24%, respectively). In conclusion, this retrospective analysis showed that neoadjuvant GS therapy might be more effective than the standard surgery-first strategy in terms of oncological outcomes for resectable pancreatic cancer. A prospective randomized study, Prep-02/JSAP-05, which compares neoadjuvant therapy to the surgery-first approach, is ongoing (UMIN-No. 000009634).

Background/aims: Patients with intraductal papillary-mucinous neoplasm (IPMN) of the pancreas are likely to have a better prognosis than those with conventional pancreatic ductal adenocarcinoma. Recently there have been some reports on extrapancreatic malignant neoplasms (EPM) occurring in patients with IPMN. The purpose of this study was to discover the characteristic features of IPMN with EPM compared with IPMN without EPM., Methods: 61 patients with IPMN who underwent surgery at Tohoku University Hospital between 1988 and 2006 were retrospectively analyzed., Results: The 61 patients with IPMN in this study comprised 25 with intraductal papillary-mucinous adenomas (IPMA) and 36 with intraductal papillary-mucinous carcinomas (IPMC) including 6 with invasive carcinomas. Synchronous and metachronous EPM were observed in 15 out of the 61 patients (24.6%). Three of these patients, including 2 with IPMA and 1 with invasive carcinoma associated with IPMC, died of the EPM. None of the features, including sex, age, smoking, family history, macroscopic types (main duct type or branch duct type), histological types (gastric, intestinal, pancreatobiliary or oncocytic), and aberrant expression of molecules including CDKN2A, TP53, SMAD4 and DUSP6, except for the histological diagnoses were associated with the occurrence of EPM, i.e., the EPM occurred more often in patients with IPMA (10 out of 25) than in those with IPMC (5 out of 36) in our series (p = 0.0199 by the chi(2) test, p = 0.0330 by Fisher's exact probability test, p = 0.0422 by Yates' correction)., Conclusion: Patients with IPMA were more likely to have EPM than those with IPMC. Patients with IPMA are usually expected to have a fair prognosis but EPM could be fatal in some of them, so it must be noted during follow-up., (Copyright 2008 S. Karger AG, Basel and IAP.)