Comparison of CEA and CA19-9 as a predictive factor for recurrence after curative gastrectomy in gastric cancer.

BACKGROUND: Our aim of was to compare importance of the tumor markers (TMs) serum carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 in prediction of recurrence after curative gastrectomy for gastric cancer. METHODS: We reviewed retrospectively the clinical records of 149 patients who underwent curative gastrectomy for stage I-III gastric cancer and whose CEA and CA19-9 levels were determined once preoperatively and for more than 3 years postoperatively. We investigated whether the clinicopathological characteristics of patients including age, sex, pathological disease stage, operative approach, type of gastrectomy, and degree of lymph node dissection as well as preoperative positivity of CEA and CA19-9 were risk factors for recurrence in univariate and multivariate analyses. Rate of recurrence was compared between patients positive and negative for postoperative CEA or CA19-9. We also calculated sensitivity, specificity, positive and negative predictable values of postoperative positivity of CEA and CA19-9 for recurrence. The lead time was compared between CEA and CA19-9 that was defined as the time of the first detection of increases in tumor markers and confirmation of recurrence on imaging modalities. RESULTS: The number of patients positive for preoperative CEA was 25 (17%) and for CA19-9 was 11 (7%). Recurrence was confirmed in 29 (19%) patients. Stage III disease, preoperative positivity for CA19-9 but not CEA, and total gastrectomy were risk factors for recurrence in univariate analysis, but stage III disease was the only risk factor for recurrence in multivariate analysis. Forty and 15 patients were positive for postoperative CEA and CA19-9, respectively. The recurrence rate of 47% (7/15) in patients positive for postoperative CA19-9 was greater than that in negative patients (22/134 = 16%), but it did not differ between patients who were positive or negative for postoperative CEA. Specificity for CA19-9 was greater than that for CEA (P < 0.05). The lead time of CEA (3.9 ± 4.7 months) was not different from that of CA19-9 (6.1 ± 7.1 months). CONCLUSIONS: These results indicate that CA19-9 rather than CEA is likely to be more useful for the detection of recurrence after curative gastrectomy for gastric cancer.

CD109 promotes the tumorigenic ability and metastatic motility of pancreatic ductal adenocarcinoma cells.

BACKGROUND: Accumulating evidence indicates that CD109, a glycosylphosphatidylinositol-anchored glycoprotein, is highly expressed in human epithelial carcinomas of multiple organs including the pancreas, but its functional role in carcinoma development has not yet been fully clarified. The aim of this study was to investigate the role of CD109 in the malignancy of pancreatic ductal adenocarcinoma (PDAC). METHODS: PDAC specimens of 145 cases were immunostained for CD109, and correlations between CD109 expression and clinicopathological conditions were analyzed. CD109 expression in PANC-1 cells, a PDAC-derived cell line, was decreased by siRNA or shRNA and its effect on the malignancy of PANC-1 cells was examined. RESULTS: Suppression of CD109 expression in PANC-1 cells resulted in reduction of in vitro cell motility and tumorigenicity in xenografts. Based on these results, we investigated the relationship between CD109 expression and metastasis of PDAC using tumor tissue specimens. Among 106 recurrent cases of 145 PDAC, there was a tendency for CD109-positive cases to be accompanied by distant metastasis. CONCLUSIONS: CD109 plays a critical role in the promotion of tumorigenic ability and cellular motility relating to metastasis of PDAC cells.

Influence of age on postoperative complications especially pneumonia after gastrectomy for gastric cancer.

BACKGROUND: The aim of this study was to investigate the influence of patients' age on postoperative morbidities including pneumonia. METHODS: We reviewed the clinical records of 211 patients with stages I - III gastric cancer undergoing curative distal gastrectomy (DG) or total gastrectomy (TG). Patients were classified into an elderly (≧80 y.o.) or a control (< 80 y.o.) group. We compared patient characteristics (sex ratio, disease stage, degree of lymph node dissection, number of retrieved lymph nodes, and type of reconstruction) and early postoperative outcomes (operation time, intra-operative blood loss, and postoperative morbidity including pneumonia, and mortality) between the two groups separately in DG and TG. RESULTS: There were 134 and 77 patients who underwent DG and TG, respectively. The numbers of patients in the elderly and control groups were 25 and 109 in DG and 12 and 65 in TG. The percentage of female patients in the elderly group was greater than that in the control group in both DG and TG. The extent of lymph node dissection did not differ between two groups in TG; in contrast in DG, the rate of a D1 dissection was greater in the elderly group than in the control group. There were no differences between the two groups in distribution of disease stage, number of retrieved lymph nodes, operation time, and blood loss in DG and in TG. Overall postoperative morbidity did not differ between two groups after DG and after TG. The rate of infectious complications in the elderly group was not different from that in the control group after DG and after TG. The incidence of pneumonia was more frequent in the elderly group compared to the control group after DG (8% vs. 1%, P < 0.05) but not after TG (17% vs. 5%). When patients were compared between the elderly and the control groups regardless of type of gastrectomy, the incidence of pneumonia in the elderly group (4/37 (11%)) was greater than that in the control group (4/174 (2%), P < 0.05). CONCLUSIONS: These results suggest that pneumonia is increased in patients older than 80 years after DG.

Feasibility Assessment of Modified FOLFOX-6 as adjuvant treatment after resection of liver metastases from colorectal cancer: analyses of a multicenter phase II clinical trial (Miyagi-HBPCOG Trial-001).

BACKGROUND/AIMS: This multicenter and single arm phase II clinical trial was performed to examine the safety and efficacy of modified FOLFOX6 (mFOLFOX6) as adjuvant treatment after resection of liver metastases from colorectal cancer. METHODOLOGY: Patients who had undergone R0-1 resection of liver metastases were assigned to 12 cycles of mFOLFOX6. The primary end point was disease-free survival (DFS). RESULTS: We enrolled 49 cases and analyzed adverse events in 48 cases, since in one patient cancer recurred before starting treatment. As to the relative dose intensity, 5-FU was 78.8%, and oxaliplatin was 75.9%. Adverse events of Grade 3 and above includ- ed 18 cases of neutropenia (37.5%), 4 cases of sensory neuropathy (8.3%), 4 cases of thrombocytopenia (8.3%) and 4 cases of allergy (8.3%), and there were no cases of fatality caused by adverse events. The most difference of adverse event compared with MOSAIC trial (Multicenter International Study of Oxaliplatin/5FU-LV in the Adjuvant Treatment of Colon Cancer) was thrombocytopenia. The 2-year DFS was 59.2% (95% CI: 36.7-78.4) in the 49 enrolled cases. CONCLUSION: mFOLFOX6 after hepatectomy was tolerable. And mFOLFOX6 also seemed to improve DFS. mFOLFOX is one of the options for such patients and appears promising as an adjuvant treatment.

Direct peroral cholangioscopy with red dichromatic imaging 3 detected the perihilar margin of superficial papillary extension in a patient with intraductal papillary neoplasm of the bile duct.

Intraductal papillary neoplasms of the bile duct (IPNB) are a tumor derived from bile duct epithelium that tends to spread laterally and non-invasively. Surgery is the first-choice treatment for IPNB. It is extremely important to accurately diagnose the extent of lateral tumor extension. Although peroral cholangioscopy (POCS) is a potentially useful modality for detecting tumor range with direct observation, poor image quality is a limitation of POCS. Recently, a new-generation endoscopy system (EVIS X1) was equipped with functions such as red dichromatic imaging to improve image quality. A 75-year-old man with cholangitis was referred to our department. Various imaging studies showed a mass in the middle to lower bile duct and dilatation of the common bile duct and the intrahepatic bile duct. Endoscopic retrograde cholangiopancreatography was performed. A biopsy of the main tumor in the lower common bile duct revealed IPNB. It was difficult to determine the extent of superficial tumor extension with modalities such as contrast-enhanced computed tomography, magnetic resonance imaging, and endoscopic ultrasonography but the detailed evaluation was possible using POCS with red dichromatic imaging 3. The patient underwent hepatopancreatoduodenectomy. This case suggests the usefulness of direct observation using POCS with red dichromatic imaging 3 to determine the range of IPNB.

Lymph nodes metastasis is a risk factor for bone metastasis from extrahepatic cholangiocarcinoma.

BACKGROUND/AIMS: The rate and site of bone metastasis from cholangiocarcinoma as well as the prognosis are unclear. Therefore, we intend to make a comparative review of the background to bone metastasis, examine a high-risk group for bone metastasis and use the data towards the improvement in quality of life. METHODOLOGY: We studied 200 cases of cholangiocarcinoma resected in our division from January 2003 to April 2010. RESULTS: Bone metastasis was confirmed in four cases (2.0%). The survival period after the diagnosis of bone metastasis ranged from 2.9 months to 21.6 months and the average was 6.7 months. We studied histopathological findings of bone metastasis, lymph node metastasis, lymphatic invasion, blood vessel invasion and perineural invasion (ly, v and pn) and found that all of four bone metastasis cases were positive for lymph node metastasis which was a statistically significant factor affecting bone metastasis. CONCLUSIONS: Since the number of cases we studied is small, it is difficult to determine whether lymph node metastasis is a risk factor for bone metastasis; however, we think it is necessary to take the probability of bone metastasis into consideration when we provide medical care to patients positive for lymph node metastasis.

An analysis of a second-line S-1 monotherapy for gemcitabine-refractory biliary tract cancer.

BACKGROUND/AIMS: Gemcitabine is widely used as a first-line therapy for biliary tract cancer (BTC). However, few studies have been conducted to analyze second- line therapies. METHODOLOGY: From 33 patients who had been administered gemcitabine following resection between May 2005 and August 2007, we retrospectively analyzed the safety and efficacy of S-1 in 11 cases who received S-1 as second-line therapy due to recurrence or relapse of the primary disease. RESULTS: Among the adverse events (AEs) observed during S-1 administration, the most common was a decrease in the concentration of hemoglobin, followed by thrombocytopenia. No Grade 4 AEs or worse were detected. In addition, the AEs and their respective severity strongly resembled those of gemcitabine used as a first-line therapy. There were 7 cases that could be evaluated according to RECIST criteria, of which 1 was considered in the partial response and 3 as stable disease. The medians of time to progression after S-1 administration and survival after S-1 administration were 5.6 months and 31 months, respectively. CONCLUSIONS: S-1 could be taken safely as a second-line therapy without provoking severe AEs. By preventing the cessation of S-1 administration due to its AEs, more continued S-1 administration could lead to a better prognosis for BTC.

[A case of curatively resected locally advanced cancer of the pancreatic body treated by distal pancreatectomy with en bloc celiac axis resection after neoadjuvant chemotherapy].

A 68-year-old man with locally advanced pancreatic body cancer invading the celiac axis(CA, including common hepatic artery)and in contact with the superior mesenteric artery(SMA)underwent 2 courses of neoadjuvant chemotherapy(NAC); gemcitabine hydrochloride(GEM 1,000 mg/m / / 2, on day 1 and 15)and S-1(100mg/m2day, 2-weeks of continuous administration followed by 1-week rest). The tumor volume and the contact area to SMA were greatly diminished. All tumor markers were reduced. He underwent R0 resection by distal pancreatectomy with en bloc celiac axis resection(DP-CAR). After the surgery, he could continue adjuvant chemotherapy; (GEM 1,000 mg/m2)only twice because of malnutrition. Nine months later CT revealed local recurrence and multiple lung metastases. The patient died 371 days after surgery. Appropriate NAC can contribute to R0 resection in locally advanced pancreatic cancer.

Phase I trial of neoadjuvant chemoradiation with gemcitabine and surgical resection for cholangiocarcinoma patients (NACRAC study).

BACKGROUND/AIMS: The feasibility of neoadjuvant chemoradiation therapy for cholangiocarcinoma, followed by conventional resection, has not been determined yet. Here, a phase I study of neoadjuvant chemoradiation therapy, named NACRAC, was performed to determine the maximum tolerated dose (MTD) and the recommended dose (RD) of gemcitabine when combined with external beam radiation therapy for resectable cholangiocarcinoma. METHODOLOGY: From August 2007 to June 2008, 12 patients provided informed consent. Preoperative radiation was administered in 1.8Gy daily fractions up to a total dose of 45Gy. Gemcitabine was administered at day 1 and 8 every three weeks. The initial dose of gemcitabine was started from 400mg/m2. RESULTS: One patient was not able to start treatment because of bleeding caused by a duodenal ulcer and cholangitis. At 800mg/m2 of gemcitabine, one patient out of three failed to complete the treatment because of Grade 3 hematological toxicity. In another three cases of 800mg/m2, the second case could not complete the treatment because of cholangitis. Then, 600mg/m2 was determined to be the MTD, and the RD dose decided as 600mg/m2. CONCLUSIONS: The RD of gemcitabine in NACRAC study was determined to be 600mg/m2. NACRAC study should proceed to a phase II trial to evaluate the effectiveness.

Biliary Schwannoma That Required Differentiation from Bile Duct Cancer.

Schwannomas are benign tumors originating from Schwann cells, which are the main component of the neural sheath. Biliary schwannomas are extremely rare. We report the case of a 78-year-old man who presented with no abdominal symptoms or jaundice. CT imaging showed a hyperdense mass extending along the extrahepatic bile duct, and the upstream bile ducts were dilated. We performed extrahepatic bile duct resection under a preoperative diagnosis of the extrahepatic bile duct cancer. A histopathological examination of the resected specimen revealed that the tumor consisted of spindle cells which exhibited a palisading arrangement. Immunohistochemical staining was positive for protein S-100 and vimentin. Based on these pathological findings, we diagnosed the patient with schwannoma of the extrahepatic bile duct. Our search of the relevant literature revealed 19 case studies of biliary schwannomas. In our case, the surgical findings showed that the tumor was noninvasive and mobile. During surgery, a fast frozen section analysis was performed, and no malignant findings were observed. These results enabled us to avoid extrahepatic bile duct resection with major hepatectomy. We experienced a case of biliary schwannoma that was difficult to distinguish from bile duct cancer.

[Diagnosis and treatment of liver metastases].

Approximately 35-60% of patients with colorectal cancers will develop liver lesions during their life span. Previously colorectal liver metastases have traditionally been categorized as incurable systemic disease. However, the introduction of new chemotherapeutic regimens(e.g. FOLFOX or FOLFIRI)and recent technical innovations(e. g. staged hepatic resection and percutaneous transhepatic portal embolization)has allowed us to perform hepatic resection with curative intent. Additionally, a neoadjuvant strategy has expanded the criteria for liver resection, and more active molecular therapeutic agents are now available. As a result, a recent advancement has enhanced the overall 5-year survival from 30% to 58% for colorectal liver metastases. Despite these facts, many patients still experience a recurrence after hepatic resection. Modern treatment of colorectal liver metastases requires a multimodal approach to increase the number of patients who may benefit from surgical treatment of colorectal liver metastases.

[Long-term survival case after liver resection and postoperative hepatic arterial infusion for multiple liver metastases from rectal cancer].

A 45-year-old man underwent a low anterior resection for rectal cancer [T3, N1, M0, Stage IIa: UICC]. He received a postoperative systemic chemotherapy with 5-FU and LV. Five months after the operation, multiple liver metastases were detected in the right hepatic lobe (S5, 6, 8). Right hepatectomy was performed. Seventeen courses of postoperative hepatic arterial infusion (HAI) chemotherapy (weekly high-dose 5-FU regimen) were performed without severe adverse events. He was still alive with no sign of recurrence for 69 months after hepatectomy. After liver resection for metastases of colorectal cancer, although a systemic chemotherapy has been mainly performed, HAI chemotherapy is one of the important options for prevention of local recurrence.

BEX2 suppresses mitochondrial activity and is required for dormant cancer stem cell maintenance in intrahepatic cholangiocarcinoma.

Cancer stem cells (CSCs) define a subpopulation of cancer cells that are resistant to therapy. However, little is known of how CSC characteristics are regulated. We previously showed that dormant cancer stem cells are enriched with a CD274low fraction of cholangiocarcinoma cells. Here we found that BEX2 was highly expressed in CD274low cells, and that BEX2 knockdown decreased the tumorigenicity and G0 phase of cholangiocarcinoma cells. BEX2 was found to be expressed predominantly in G0 phase and starvation induced the USF2 transcriptional factor, which induced BEX2 transcription. Comprehensive screening of BEX2 binding proteins identified E3 ubiquitin ligase complex proteins, FEM1B and CUL2, and a mitochondrial protein TUFM, and further demonstrated that knockdown of BEX2 or TUFM increased mitochondria-related oxygen consumption and decreased tumorigenicity in cholangiocarcinoma cells. These results suggest that BEX2 is essential for maintaining dormant cancer stem cells through the suppression of mitochondrial activity in cholangiocarcinoma.

ZD1839 (IRESSA) stabilizes p27Kip1 and enhances radiosensitivity in cholangiocarcinoma cell lines.

The prognosis of cholangiocarcinoma patients is extremely poor despite the aggressive multidisciplinary cancer therapies that have been used clinically (1). Recently, molecular target therapy has attracted attention. Epidermal growth factor receptor (EGFR) tyrosine kinase (TK) is a promising target for anticancer therapy. ZD1839 (IRESSA) is an orally active, selective inhibitor of EGFR-TK. This study examined the effects of ZD1839 in TFK-1 and HuCCT1, the human cholangiocarcinoma cell lines that express EGFR. Somatic mutations in the TK domain of the EGFR gene are associated with the sensitivity of lung cancers to ZD1839 (2). In the analysis of the EGFR sequence, no mutations were found in TFK-1 and HuCCT1. The TFK-1 and HuCCT1 cells showed almost the same sensitivity to ZD1839. It is shown that ZD1839 induced apoptotic cell death of TFK-1 cells as indicated by apoptotic morphological changes and an enhancement of TUNEL-positive cells. ZD1839 produced a dose-dependent inhibition of cellular proliferation in TFK-1. Cell cycle analysis demonstrated that ZD1839 induces G1 arrest. Moreover, concurrent evaluation of the expression of p27(Kip1) protein and Jun activating domain-binding protein 1 (Jab1) with ZD1839 by Western blotting analysis was performed. It was found that ZD1839 activity causes an increase of p27(Kip1) stability that correlates with Jab1 down-regulation. Thus, ZD1839 affects key cellular pathways, controlling cell proliferation and apoptosis. Furthermore, the treatment of TFK-1 with ZD1839 reduced the cell survival after radiation exposure. ZD1839 in combination with radiation produced a dose-dependent and synergic inhibitory effect on cellular proliferation. In conclusion, these results suggest that ZD1839 may have clinical activity against cholangiocarcinoma.

Overexpression of adenovirus-mediated p27kip1 lacking the Jab1-binding region enhances cytotoxicity and inhibits xenografted human cholangiocarcinoma growth.

The cyclin-dependent kinase inhibitor (CDK1) p27(kip1) is a negative regulator of cell cycling and has antitumor effects. In our previous study, the recombinant adenovirus expressing wild-type p27(kip1) (Adp27-wt) induced cell cycle arrest and apoptosis, and proved that p27 is a tumor suppressor gene like p53. Another adenovirus vector expressing mutant p27(kip1) (Adp27-mt), which inhibited degradation by the ubiquitin-proteasome system, showed increased protein stability and caused a stronger induction of apoptosis. Recently, the p27(kip1) protein binding with Jab1 (Jun activating binding protein 1) was found to translocate from the nucleus into the cytosol, and then become degraded by the 26S proteasome system. The inhibition of nuclear-cytoplasmic translocation increases the protein stability of p27(kip1) and p27(kip1) with a deletion of the Jab1-binding region (p27-jab-d) is not translocated and not degraded. Therefore, a new recombinant adenovirus (Adp27-jab-d) expressing p27-jab-d was made which was able to induce greater cytotoxicity. Adp27-jab-d inhibited the growth of human cholangiocarcinoma cell line (TFK-1) cells in vitro at 3.3 times (IC(50)) lower concentration than Adp27-wt. Moreover, in a xenografted severe combined immuno-deficient (SCID) mouse model injected with TFK-1 cells in the subcutaneous tissue, treatment by intratumor injection of Adp27-jab-d once a day for 3 days after the tumor was established, inhibited tumor growth more strongly than Adp27-wt or Adp27-mt and even induced tumor regression. However, the flow cytometric TUNEL assay showed little enhancement of apoptosis. Adp27-jab-d was thought to induce not only apoptosis but also necrosis, which was due to a specific effect of the Adp27-jab-d. Thus, by enhancing the cytotoxicity through inhibiting the translocaton of p27(kip1), p27(kip1) lacking the Jab1-binding region might be useful for cancer therapy. The control protein localization might also be a new target not only for cancer treatment, but also other diseases.

Clock gene mouse period2 overexpression inhibits growth of human pancreatic cancer cells and has synergistic effect with cisplatin.

Circadian rhythms are the daily oscillations of multiple biological processes regulated by an endogenous clock. The Period2 gene is essential in controlling the circadian rhythm and plays an important role in tumor suppression. We examined whether the overexpression of the mouse Period2 gene (mPer2) in cultured tumor cells from human tissues inhibits cell growth, using the recombinant adenovirus vector AdmPer2. The overexpression of mPer2 in human pancreatic cancer cells (Panc1, Aspc1) reduced cellular proliferation and induced apoptotic cell death. Infection with AdmPer2 also inhibited cell-cycle progression, inducing arrest at the G(2)-M phase. Western blotting analyses confirmed that infection with AdmPer2 reduced Bcl-X(L), Cdc2 and cyclin B1 protein, whereas it increased Bax protein in Aspc1 cells. The overexpression of mPer2 suppressed Cdc2 kinase activity. Moreover, infection with AdmPer2 resulted in dose-dependent synergic cell killing effects with the anticancer agent cisplatin (CDDP) in human pancreatic cancer cells. This synergic effect might be related to the reduction of Bcl-X(L) induced by infection with AdmPer2. Our results suggest that the circadian gene Period2 may play an important role in suppression of cell proliferation in human cancer, and additionally Period2 gene expression level may influence the sensitivity to cisplatin depending on Bcl-X(L) expression level.

Up-regulated p27Kip1 reduces matrix metalloproteinase-9 and inhibits invasion of human breast cancer cells.

BACKGROUND: p27Kip1 is a cyclin-dependent kinase inhibitor which has been reported to be associated with invasion, metastasis and angiogenesis in malignant tumors, but its mechanism of action remains unknown. Here, it was examined whether p27Kip1 has an inhibitory effect on cancer cell invasion and correlates with matrix metalloproteinase expression (MMPs). MATERIAL AND METHODS: The human breast cancer cell line MDA-MB-231 and MDA-MB-231 transfectedp27Kip1 MDA-MB-p27 were used for the invasion assay, Western blotting and real-time quantitative RT-PCR. RESULTS: In the invasion assay, the invasion of MDA-MB-p27 was significantly less than that of the parent cell line. In Western blotting analyses, the protein level of MMP-9 was also reduced in MDA-MB-p27. Furthermore, the activity of MMP-9 in cell culture supernatants was lower in MDA-MB-p27 as compared with enzyme-linked immunosorbent assays. In real-time quantitative RT-PCR, the mRNA level of MMP-9 was lower in MDA-MB-p27 cells. CONCLUSION: Up-regulation of p27Kip1 remarkably inhibited the invasion of the breast cancer cells, in part due to the reduced expression of MMP-9. This is the first report of p27Kip1 modulating MMP-9 and indicating that p27Kip1 might play a key role in tumor cell invasion.

Pyruvate kinase type M2 contributes to the development of pancreatic ductal adenocarcinoma by regulating the production of metabolites and reactive oxygen species.

The majority of cancer cells maintain a high glycolytic activity and an increased lactate production, even in a well oxygenated environment. This phenomenon is known as the Warburg effect. Previous studies have revealed that various types of cancer selectively express the pyruvate kinase M2 isoform (PKM2), and that PKM2 plays a pivotal role in the Warburg effect. Although elevated PKM2 levels have been observed in pancreatic cancer and other types of cancer, little is known about the biological function of PKM2. In this study, in order to examine the expression and role of PKM2 in pancreatic ductal adenocarcinoma (PDAC), we knocked down PKM2 in PDAC cells by introducing small interfering and short hairpin RNAs, and examined the gene expression profiles in the cells by microarray analysis. We analyzed the energy-producing pathways in the cells by XFe Extracellular Flux Analyzers, and detected intracellular metabolites by capillary electrophoresis time-of-flight mass spectrometry. We found that the RNAi-mediated knockdown of PKM2 diminished the proliferative, migratory and tumorigenic ability of the PDAC cell-lines. PKM2 knockdown also resulted in lower glycolytic activities and decreased levels of some intracellular metabolites, such as pyruvate and polyamine; however, it led to elevated levels of reactive oxygen species. Microarray analysis revealed the functional association between PKM2 and the expression of genes that drive the cell cycle. On the whole, the findings of this study demonstrate that PKM2 plays an important role in metabolic activities, as well as in the malignancy of PDAC cells.

Drug delivery of oral anti-cancer fluoropyrimidine agents.

INTRODUCTION: Sixty years since its introduction, 5-FU still forms the core of chemotherapy regimens for many types of malignancies. 5-FU is a time-dependent drug but is rapidly degraded in plasma by dihydropyrimidine dehydrogenase (DPD). Although originally developed in an intravenous form, 5-FU oral prodrugs were developed with the goal of improving efficacy and minimizing toxicity as well as to capitalize on the advantages of oral drug administration. The inactive 5-FU prodrug is gradually converted into the active form in the systemic circulation. UFT, S-1, and capecitabine are oral 5-FU prodrugs currently in clinical use. However, the efficacy of 5-FU can be further improved by its combination with DPD inhibitors and biochemical modulators, such as uracil and leucovorin, in addition to modifying administration schedules. Areas covered: We focused on the drug delivery of oral 5-FU prodrugs, their pharmacokinetics, and the development of DPD inhibitors. Since oral 5-FU prodrugs have been formulated into combination drugs, we also discussed the regulatory approval of combination drugs. Expert opinion: Many regimens that include intravenously administered 5-FU can be replaced by oral 5-FU prodrugs. Patients would benefit from development of combination 5-FU oral prodrug formulations and its associated path through the combination drug regulatory approval process.