Correlation between the Carbon Nanotube Growth Rate and Byproducts in Antenna-Type Remote Plasma Chemical Vapor Deposition Observed by Vacuum Ultraviolet Absorption Spectroscopy.

For sp2 or sp3 carbon material growth, it is important to investigate the precursors or intermediates just before growth. In this study, the density of ethylene (C2 H4 ) outside the plasma discharge space and just before reaching the carbon nanotube (CNT) growth region is investigated by vacuum ultraviolet absorption spectroscopy for plasma discharge in an antenna-type remote plasma chemical vapor deposition with a CH4 /H2 system, with which the growth of very long (≈0.5 cm) CNT forests is achieved. Single-wall CNT forests have the potential for application as electrodes in battery cells, vertical wiring for high current applications, and thermal interface materials. It is observed that the plasma discharge decomposes the CH4 source gas and forms C2 Hx species, which reversibly reform to C2 H4 in the plasma-off state. In addition, the density of the formed C2 H4 has a strong correlation to the CNT growth rate. Therefore, the C2 H4 density is a good indicator of the density of C2 Hx species for CNT growth in the CH4 /H2 plasma system.

Effects of menthol on the pharmacokinetics of triazolam and phenytoin.

We have previously shown that menthol attenuates the anticoagulant effect of warfarin by increasing the expression levels of CYP3A and CYP2C in the liver. This study evaluated the effects of menthol on the pharmacokinetics of the CYP3A substrate triazolam and the CYP2C substrate phenytoin. Menthol was orally administered to mice for 7 d. Twenty-four hours after the administration of menthol, triazolam was orally administered, and the plasma concentration was measured. In addition, the CYP3A metabolic activity for triazolam and the CYP3A expression level in the liver were determined. The effects of menthol on the pharmacokinetics of phenytoin were assessed in the same manner. In the menthol-treated group, the area under the blood concentration-time curve (AUC) of triazolam was lower and its clearance was higher compared with the control group. The CYP3A metabolic activity and CYP3A expression level in the liver were significantly increased in the menthol-treated group compared with the control group. Similarly, the AUC of phenytoin was lower and the hepatic CYP2C expression level was higher in the menthol-treated group. Thus, menthol lowered the plasma concentrations of triazolam and phenytoin when concurrently administered. These effects may be attributed to an increased metabolic activity for these drugs due to the increased expression of CYP3A and CYP2C in the liver.

A single surgeon's experience of 65 cases of penoplasty for congenital megaprepuce, with special reference to mid- to long-term follow-up.

PURPOSE: There are few reports about postoperative outcome of penoplasty (PP). We present the results of mid- to long-term follow-up of PP performed for congenital megaprepuce (CMP). METHODS: Data from 65 CMP cases treated by PP performed by a single surgeon from 2000 to 2014 were collected prospectively. All cases were treated using the technique reported by Cuckow (Pediatric surgery. Springer, Berlin, pp 543-554, 2006). RESULTS: Mean age at PP was 5.9 years (range 0.4-13.9). All cases presented as infants and some 12 cases (18.5 %) had PP when 10 or more years old. There were no intra- and postoperative complications. Mean duration of follow-up was 3.6 years (range 0.1-17.5). Duration of follow-up was 4 years or less in 48 (73.8 %), 5-9 years in 13 (20.0 %), and 10 or more years in 4 (6.2 %). While postoperative penile cosmesis was good in 63/65 (96.9 %) cases without scrotal deformity, 2/65 (3.1 %) had redundant penile skin excised upon the recommendation of the treating surgeon even though the patients and parents were unconcerned. CONCLUSION: Mid- to long-term follow-up of our PP cases shows that outcome is cosmetically acceptable and stable.

[A case of gastric cancer with peritoneal dissemination-efficacy of combination therapy with S-1 and docetaxel].

The efficiency of new anti-cancer drugs such as the S-1 system was demonstrated in a controlled study comparing treatment and non-treatment groups. We encountered a patient with gastric cancer demonstrating peritoneal dissemination, who was successfully treated by combination therapy using S-1 and docetaxel. A 62-year-old woman was admitted to the hospital due to appetite loss and nausea. Upper GI endoscopy demonstrated a type 3 gastric cancer extending from the upper to lower body of the stomach. In the pelvic cavity, an abdominal CT scan demonstrated massive ascites. An abnormally high CA72-4 (143.8 U/mL) level was detected in serum. Treatment with S-1 and docetaxel was started with the following regimen: daily oral administration of 80 mg/body S-1 for 14 days, followed by a 7-day rest and infusion of 40 mg/m2 docetaxel on day 1. After 4 courses, the sites of dissemination had disappeared, and the serum CA72-4 value returned to normal. The patient clinically achieved good QOL by this method, which was very effective for non-resected gastric cancer with peritoneal dissemination.

Evaluation of the 5-fluorouracil plasma level in patients with colorectal cancer undergoing continuous infusion chemotherapy.

5-Fluorouracil (5-FU) dosing has traditionally been based on the body surface area (BSA) in colorectal cancer treatment. However, there is accumulating evidence that dosing based on BSA may be of limited use. The purpose of the present study was to evaluate the changes in 5-FU plasma levels and tumor response as well as the severity of adverse events in patients with cancer treated with 5-FU combined chemotherapy. The dosing amount of 5-FU was determined based on the BSA. Blood samples were collected, and 5-FU plasma levels in 15 patients with colorectal cancer were measured three times (0, 22 and 40 h before and after the start of infusion) during constant-infusion of 5-FU for 46 h by an immunoassay. 5-FU plasma levels were significantly higher at 22 and 40 h compared with at 0 h (P<0.001), when all 15 patients were analyzed. Notably, the tumor response of the partial response/stable disease group showed significant increases in 5-FU plasma levels at 40 h compared with at 22 h (P<0.01), while the progressive disease group showed no significant increase. In addition, the 5-FU plasma level in the adverse event level of grade ≥2 was higher than that of grade <2 at 40 h after the start of infusion. Collectively, these observations indicated that during continuous infusion of 5-FU, the 5-FU plasma level increased significantly, and the tumor response (such as partial response, stable or progressive disease) may be influenced by the increase of 5-FU plasma level from the start of infusion. Therefore, the 5-FU plasma level may be a predictive factor for maximizing the tumor response and minimizing the risk of severe adverse events.

Impact of primary tumor location as a predictive factor in patients suffering from colorectal cancer treated with cytotoxic anticancer agents based on the collagen gel droplet-embedded drug sensitivity test.

In recent studies, better clinical outcomes for patients with left-sided colon cancer (CC) compared with right-sided CC have been reported; however, in such investigations, the chemotherapy regimens included molecular-targeting agents. To the best of our knowledge, the impact of primary tumor location as a predictive factor in patients suffering from CC treated with cytotoxic anticancer agents alone has not been investigated. The aim of the present study was to determine the impact of the primary tumor location as a predictive factor of patients undergoing the following cytotoxic anticancer agent regimens: Leucovorin and fluorouracil + oxaliplatin (FOLFOX) or Leucovorin and fluorouracil + irinotecan (FOLFIRI), using the collagen gel droplet-embedded drug sensitivity test (CD-DST). Between March 2008 and April 2017, tumor specimens were obtained from 133 patients suffering from colorectal cancer (CRC) who had not received preoperative chemotherapy. CD-DST was performed and the growth inhibition rate (IR) was determined in FOLFOX and FOLFIRI regimens. The associations between tumor location and IR values for each condition were evaluated. In the present study, the prognosis of patients receiving palliative chemotherapy as well as treatment with molecularly-targeted agents was also investigated. There were no significant differences in the IRs (%) of the two regimens using CD-DST for right-sided tumors compared with left-sided tumors, including or excluding the rectum. The median survival times of patients with right CC and left CC who had received palliative chemotherapy and treatment with molecularly-targeted agents were 960 and 1,348 days, respectively. Primary tumor location did not represent a predictive factor for the efficacy of treatment with cytotoxic anticancer agent regimens using CD-DST. However, patients suffering from left-sided CC were revealed to exhibit better clinical outcomes compared with patients suffering from right-sided CC when molecularly-targeted agent regimens were administered. Therefore, the results of the present study suggested that molecularly-targeted agents rather than cytotoxic anticancer agents may result in improved clinical outcomes for patients with CRC suffering from left-sided tumors.

Impact of the individualization of the first-line chemotherapy for advanced colorectal cancer based on collagen gel droplet-embedded drug sensitivity test.

Leucovorin (FOL) and fluorouracil (5-FU) plus oxaliplatin (l-OHP; FOLFOX) or FOL and 5-FU plus irinotecan (SN-38; FOLFIRI) are widely used as first-line chemotherapy regimens in the treatment of advanced colorectal cancer (CRC). However, second-line chemotherapy must be abandoned in certain cases due to disease progression, adverse effects or high medical cost. Therefore, the most effective regimen should be selected as first-line chemotherapy. We reported that individualization of first-line treatment (FOLFOX/FOLFIRI/Dual/Poor responder) was possible using the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) and that individualized first-line chemotherapy with CD-DST may improve the prognosis of patients with unresectable CRC. The aim of the present prospective cohort study was to evaluate the individualization of first-line chemotherapy using CD-DST, with a focus on prognosis. Between March 2008 and December 2015, tumor specimens were obtained from 120 patients with CRC who had not received preoperative chemotherapy. CD-DST was performed and the growth inhibition rate (IR) was determined by exposure for 24 h with 5-FU and l-OHP (6.0 and 3.0 µg/ml, respectively) and 5-FU and SN-38 (6.0 and 0.2 µg/ml, respectively). The cumulative distribution of IR values under each condition was evaluated on the basis that the clinical response to FOLFOX and FOLFIRI is equivalent (~50%). The prognosis of dual responder was improved compared with that of poor responders, however this difference was identified to be significant. There was no different prognosis between patients treated with an appropriate first-line regimen and patients treated with an inappropriate first-line regimen in dual responders. However, in poor responders, there were significant differences of prognosis between patients treated with an appropriate first-line regimen and patients treated with an inappropriate first-line regimen (P=0.036). In conclusion, the results from the present study suggest that administration of the recommended first-line regimen using CD-DST for patients with unresectable CRC is important for the improvement of prognosis, particularly in poor responders.

Efficacy and safety of neoadjuvant chemotherapy with oxaliplatin, 5-fluorouracil, and levofolinate for T3 or T4 stage II/III rectal cancer: the FACT trial.

PURPOSE: A multicenter phase II clinical study was performed in patients with T3 or T4 stage II/III rectal cancer to evaluate the efficacy and safety of neoadjuvant chemotherapy with 5-fluorouracil, levofolinate, and oxaliplatin (mFOLFOX6). METHODS: Patients received four 2-week cycles of mFOLFOX6 therapy (oxaliplatin at 85 mg/m2 + leucovorin at 200 mg/m2 + fluorouracil as a 400 mg/m2 bolus followed by infusion of 2400 mg/m2 over 46 h, all on Day 1). They were evaluated by computed tomography after completion of the fourth cycle. If there was no disease progression, two additional cycles were administered and then surgery was performed. Adjuvant chemotherapy was generally administered for 6 months using appropriate regimens at the discretion of the physician. RESULTS: mFOLFOX6 therapy was given to 52 patients with locally advanced rectal cancer. The preoperative response rate was 48.8% and the operation rate was 80.8%. Serious adverse events of Grade 3-4 were neutropenia (n = 5), leukopenia (n = 1), thrombocytopenia (n = 1), febrile neutropenia (n = 1), nausea (n = 1), vomiting (n = 1), and peripheral neuropathy (n = 2). The R0 resection rate, pathologic complete response rate, and sphincter preservation rate were 91.0, 11.9, and 73.8%, respectively. Postoperative complications were tolerable. CONCLUSIONS: The present results suggested that neoadjuvant therapy with mFOLFOX6 is safe and effective, representing a reasonable treatment option for locally advanced rectal cancer.

The relationship between 5-fluorouracil sensitivity and single nucleotide polymorphisms of the orotate phosphoribosyl transferase gene in colorectal cancer.

Orotate phosphoribosyl transferase (OPRT) is an enzyme playing an important role in exertion of the effect of 5-fluorouracil (5-FU). A type of gene polymorphism, single nucleotide polymorphism (SNP), is considered to be a factor affecting individual differences in exertion of drug effects, and its analysis has recently made progress. We investigated the correlation between SNP of OPRT and 5-FU sensitivity in colon and rectal cancers. The subjects were 31 patients with colorectal cancer who underwent surgical excision between December 2003 and July 2004 at our department. Of SNP of OPRT, 638G/C, 1050T/A, and 1336A/G located in the coding region were analyzed by invader assay. The growth inhibition rate (% IR) of colorectal cancer by 5-FU was obtained by the CDDST method, and 5-FU sensitivity was compared among strains (wild-, homo-, and hetero-types) of each polymorphism. There was no relationship between the strains and 5-FU sensitivity in any of the SNPs. The investigated SNPs of OPRT may have no major influence on 5-FU sensitivity. However, there are many unknown factors in the relationship between SNP of OPRT and 5-FU sensitivity, and SNP analysis of other regions is necessary.

Impact of chromosome 17q deletion in the primary lesion of colorectal cancer on liver metastasis.

Colorectal cancer is a prevalent malignancy worldwide, and investigations are required to elucidate the underlying carcinogenic mechanisms. Amongst these mechanisms, de novo carcinogenesis and the adenoma to carcinoma sequence, are the most understood. Metastasis of colorectal cancer to the liver often results in fatality, therefore, it is important for any associated risk factors to be identified. Regarding the treatment of the disease, it is important to manage not only the primary colorectal tumor, but also the liver metastases. Previously, through gene variation analysis, chromosomal loss has been indicated to serve an important role in liver metastasis. Such analysis may aid in the prediction of liver metastasis risk, alongside individual responses to treatment, thus improving the management of colorectal cancer. In the present study, we aimed to clarify a cause of the liver metastasis of colorectal cancer using comparative genomic hybridization analysis. A total of 116 frozen samples were analyzed from patients with advanced colorectal cancer that underwent surgery from 2004 to 2011. The present study analyzed mutations within tumor suppressor genes non-metastatic gene 23 (NM23), deleted in colorectal carcinoma (DCC) and deleted in pancreatic carcinoma, locus 4 (DPC4), which are located on chromosomes 17 and 18 and have all been reported to affect liver metastasis of colorectal cancer. The association between chromosomal abnormalities (duplication and deletion) and liver metastasis of colorectal cancer was evaluated using comparative genomic hybridization. Cluster analysis indicated that the group of patients lacking the long arm of chromosome 17 demonstrated the highest rate of liver metastasis. No significant association was observed between the frequency of liver metastases for synchronous and heterochronous colorectal cancer cases and gene variation (P=0.206). However, when these liver metastasis cases were divided into the synchronous and heterochronous types, the ratio of each was significantly different between gene variation groups, classified by the existence of the 17q deletion (P=0.023). These results indicate that the deletion of 17q may act as a predictive marker of liver metastasis in postoperative states.

Evaluation of 5-fluorouracil applicability by multi-point collagen gel droplet embedded drug sensitivity test.

The drug sensitivity of tumor cells is one of key issues to explore individualized therapy for cancer patients. One of such methods is in vitro anticancer drug sensitivity test which is generally based on one drug concentration and contact time. In this study, 5-fluorouracil (5-FU) sensitivity of cancer cells from colorectal cancer patients was evaluated by collagen gel droplet embedded drug sensitivity test (CD-DST) under multiple drug concentrations and contact durations. Cancer cells from 19 patients were measured for 9 drug concentration/contact time conditions (cohort 1) and from 34 patients were measured for 2 drug concentration/contact time conditions (cohort 2) using CD-DST. There was not significant difference in growth inhibition rate for 1.0 microg/ml for 24 h and 0.2 microg/ml for 120 h, which gives the same area under the curve (AUC) (p=0.832) in all 53 patients (cohort 1 and 2). In cohort 1, 9 conditions were successfully measured in 18 of 19 cohort 1 patients (94.7%). The drug concentrations and growth inhibition rate approximated to logarithmic curve for all 3 contact times and 50% inhibitory concentration (IC50) values at 3 contact times could be calculated in these 18 patients. Growth inhibition rate and AUC also approximated to logarithmic curve. These values varied several orders of magnitude among patients. In vitro antitumor effect of 5-FU depended on AUC in colorectal tumor and it might support the use of continuous infusion or oral therapy which generates significant AUC with manageable toxicity. Some patients demonstrating low 5-FU sensitivity could not be indicated for 5-FU based therapy, and non-5-FU therapy should be explored for them.

Impact of orotate phosphoribosyl transferase activity as a predictor of lymph node metastasis in gastric cancer.

Orotate phosphoribosyl transferase (OPRT) is an essential nucleotide metabolic enzyme for cell proliferation and also a key enzyme for conversion of 5-FU to its active form in tumor tissue. The association between tumor OPRT activity and pathophysiological status, including lymph node metastasis [pN+], and the impact of OPRT for predicting pN+ were investigated in gastric cancer. The lymph node status of 73 resectable gastric cancer patients was analyzed preoperatively by computed tomography (CT), ultrasonography and magnetic resonance, and the OPRT activity of collected tumor tissue was measured. Then these data were compared with pathological observation of a surgical lymph node specimen. OPRT activity in the tumor tissue decreased as the depth of invasion increased. An OPRT test demonstrated superior sensitivity and comparable accuracy and sensitivity for predicting pN+, against current imaging diagnoses. Furthermore, the analysis of node negative patients by CT revealed that 80% of false negative patients were retrieved by this OPRT test. Thus, OPRT activity in tumor tissue was a powerful predictor of pN+ in resectable gastric cancer, and the preoperative OPRT test, when it becomes possible, would provide a basis for accurate evaluation of disease status, which is indispensable for the planning of personalized therapy.

[Correlation between clinical pathophysiologic factors and expression of orotate phosphoribosyl transferase (OPRT), thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD) in colorectal cancer].

We measured the activity of orotate phosphoribosyl transferase (OPRT), the amount of thymidylate synthase (TS) enzyme, and the activity of dihydropyrimidine dehydrogenase (DPD) for individual tissue types in order to study the contribution of these substances to the effects of the pyrimidine fluoride anticancer drug 5-fluorouracil (5-FU). We also studied the correlation between these 3 enzymes and clinical pathophysiologic characteristics (age, sex, extent of tumor invasion, extent of metastasis to the lymph nodes, lymphatic invasion and the venous invasion of the colorectal wall). Sixty-eight patients with colorectal carcinoma who had undergone surgical resection in our department were studied. There was a significant (p < 0.01) elevation of OPRT activity in the tumor tissue compared with regions of normal tissue. OPRT activity levels in the tumor tissue were lowest in patients with mucinous carcinoma while TS enzyme levels showed the highest activity in tumor tissue in poorly differentiated adenocarcinoma. DPD also showed high activity levels in tumor tissue in poorly differentiated adenocarcinoma and mucinous carcinoma. It is possible that the expression of enzymes with respect to the antitumor effects of 5-FU is a factor contributing to the poor prognosis for patients with poorly differentiated adenocarcinoma and mucinous carcinoma. In the present study of clinical pathophysiologic characteristics, we found that metastasis to the lymph nodes was associated with a significant reduction in the OPRT tumor/normal (T/N) ratio. Our results indicate that it may be possible to predict lymphatic metastasis by determining the T/N ratio for OPRT before surgery.

Mechanism underlying the transient increase of serum iron during FOLFOX/FOLFIRI therapy.

In patients with advanced colorectal cancer (CRC), a transient significant increase of serum iron is observed during chemotherapy with leucovorin and fluorouracil plus oxaliplatin (FOLFOX) or leucovorin and fluorouracil plus irinotecan (FOLFIRI). Serum iron may be a useful and convenient predictor of the response to chemotherapy; however, the mechanism underlying its increase has not been fully elucidated. Accordingly, the mechanism underlying the elevation of serum iron during chemotherapy was investigated in 20 patients with advanced CRC who were treated between September, 2012 and July, 2013. The levels of iron, ferritin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), hemoglobin (Hb), hepcidin-25, interleukin (IL)-6 and soluble transferrin receptor (sTfR) were measured before and 48 h after chemotherapy. The serum levels of iron and hepcidin-25 were found to be significantly increased after chemotherapy (P<0.0001), whereas those of IL-6 were significantly decreased (P=0.0057). There were no significant changes in any of the other parameters. The lack of significant changes in AST, ALT and Hb suggested that the elevation of serum iron was not due to the destruction of hepatocytes, whereas the stable sTfR level suggested no destruction of erythroblasts. Hepcidin-25 regulates iron metabolism and decreases serum iron levels; it is increased by an iron load and IL-6, but is decreased under anemic or hypoxic conditions. The suppression of erythropoiesis increases serum iron levels and chemotherapy suppresses erythropoiesis. As serum iron and hepcidin-25 were both significantly increased and IL-6 was significantly decreased, with no significant changes in sTfR, it appears that the elevation of serum iron during chemotherapy may be secondary to reduced iron consumption by erythropoiesis, leading to increased expression of hepcidin-25 and suppression of Il-6 via negative feedback.

Menthol reduces the anticoagulant effect of warfarin by inducing cytochrome P450 2C expression.

Recently, it was reported that the anticoagulant effect of warfarin was reduced when patients receiving warfarin also took menthol. The purpose of this study is to reveal the mechanism of this reduced anticoagulant effect of warfarin from the pharmacokinetic point of view. Warfarin was orally administered to mice 24h after the administration of menthol for 2 days, and the plasma warfarin concentration was measured. In the menthol administration group, the area under the blood concentration time curve of warfarin was decreased by approximately 25%, while total clearance was increased to 1.3-fold compared to the control group. The hepatic cytochrome P450 (CYP) 2C protein expression level in the menthol administration group was significantly increased compared to that in the control group. An increase in the nuclear translocation of constitutive androstane receptor (CAR) was also observed. The addition of menthol to human hepatic cells, HepaRG cells, caused an increase in the mRNA expression level of CYP2C9. The results of this study revealed that menthol causes an increase in CYP2C expression levels in the liver, which leads to an enhancement of warfarin metabolism, resulting in a decreased anticoagulant effect of warfarin. It was also suggested that menthol acted directly on the liver and increased the expression level of CYP2C by enhancing the nuclear translocation of CAR.

Impact of 5-fluorouracil metabolizing enzymes on chemotherapy in patients with resectable colorectal cancer.

Although 5-fluorouracil (5-FU) is an important drug for colorectal cancer (CRC) treatment, no useful biomarker is currently available to predict treatment response. Since 5-FU is converted into active or inactive forms by orotate phosphoribosyltransferase (OPRT) or dihydropyrimidine dehydrogenase (DPD), a correlation between these enzymes and response to 5-FU has been suggested. However, such a correlation has not been investigated prospectively. Therefore, in the present study, we aimed to prospectively evaluate whether OPRT and DPD were predictive factors of the response to 5-FU treatment in patients with resectable CRC. The present investigation was designed as a multicenter prospective cohort study. OPRT and DPD activities were assessed in biopsy samples, obtained surgically from patients with resectable CRC. The OPRT/DPD ratio was calculated and the cut-off values for this ratio were determined for 5-year disease-free survival (DFS) and overall survival (OS). Patients were treated with 5-FU/leucovorin (LV) regimens and oral 5-FU. The endpoint of this study was the correlation between the OPRT/DPD ratio and 5-year DFS and OS. The cut-off value for the OPRT/DPD ratio was determined by using the maximum χ2 statistic method against 5-year DFS and OS. Sixty-eight patients were enrolled from July 2003 to May 2005. The median follow-up period was 1925 days. The OPRT/DPD ratio cut-off values for 5-year DFS and OS were 0.015 and 0.013, respectively. During the 5-year DFS and OS periods, patients with higher cut-off values had a better prognosis than those with lower ratios (P=0.03 and 0.02, respectively). In conclusion, our results suggest that the OPRT/DPD ratio could be a predictive factor for response to 5-FU/LV adjuvant chemotherapy.

Serum iron levels as a new biomarker in chemotherapy with leucovorin and fluorouracil plus oxaliplatin or leucovorin and fluorouracil plus irinotecan, with or without molecularly-targeted drugs.

Serum iron levels have been reported to increase following the administration of various anticancer drugs. An increase in serum iron levels during therapy with leucovorin and fluorouracil plus oxaliplatin (FOLFOX) or leucovorin and fluorouracil plus irinotecan (FOLFIRI) was also observed. The aim of this study was to investigate the correlation between serum iron levels and prognosis in advanced colorectal cancer (CRC) patients treated with FOLFOX/FOLFIRI ± molecularly-targeted drugs. Serum iron levels were measured prior to and at 48 h after treatment with FOLFOX/FOLFIRI ± molecularly-targeted drugs in 72 advanced CRC patients, all of whom succumbed to the disease between December, 2005 and February, 2012. No patients received radiotherapy. Taking the median rate of increase in serum iron levels as the cut-off value in each therapy, the patients were divided into cohort I (increase rate greater than the cut-off value in at least one therapy) or cohort II (increase rate less than the cut-off value in all therapies). The χ2 test and the t-test were used to compare patient characteristics between the two cohorts. Prognosis was evaluated between the two cohorts using the Kaplan-Meier method, the log-rank test and the Cox proportional hazards regression analysis. No significant bias in patient characteristics (including the frequency of chemotherapy or number of patients treated with molecularly-targeted drugs) was observed between the two cohorts. Serum iron levels were transiently elevated following treatment (P<0.001), returning to baseline within 2 weeks. Median survival time (MST) in cohort I (n=44) and cohort II (n=28) was 430 and 377 days, respectively. The MST was significantly higher in cohort I (P=0.0382). The multivariate analysis identified a small increase in serum iron levels as an independent risk factor for overall survival (OS). These results suggest that serum iron levels may be used as a new predictive factor in FOLFOX/FOLFIRI ± molecularly-targeted drug therapy. Serum iron levels may therefore prove to be a useful and convenient biomarker for OS in CRC patients.

Individualized chemotherapy for colorectal cancer based on the collagen gel droplet-embedded drug sensitivity test.

The leucovorin (FOL) and fluorouracil (5-FU) plus oxaliplatin (l-OHP; FOLFOX) or FOL and 5-FU plus irinotecan (SN-38; FOLFIRI) regimens with or without molecularly-targeted drugs are widely used as first-line chemotherapy in the treatment of advanced colorectal cancer (CRC). Whether FOLFOX or FOLFIRI is administered first is not significant, however, it is essential that full administration of the targeted dosages of all 3 drugs, 5-FU, l-OHP and SN-38, is achieved. However, this is not always possible and second-line chemotherapy must be abandoned in certain cases. Where possible, the most effective regimen should be selected as the first line of treatment. The aim of this study was to determine whether first-line chemotherapy may be individualized using the collagen gel droplet-embedded drug sensitivity test (CD-DST). Specimens of primary tumors were obtained from 43 CRC patients who had received no preoperative chemotherapy. Informed consent to measure drug sensitivity was obtained from all patients. The CD-DST allows evaluation of drug sensitivity using isolated, 3-dimensionally cultured tumor cells in a small collagen gel droplet. The CD-DST was performed and the growth inhibition rate (IR) was obtained under incubation conditions (5-FU with l-OHP at 6.0 and 3.0 µg/ml, or 5-FU with SN-38 at 6.0 and 0.2 µg/ml, respectively, for 24 h). The cumulative distributions of the growth IRs under each condition were evaluated based on the evidence that the clinical response rates to FOLFOX and FOLFIRI were almost the same. Individualization of first-line treatment was possible in all patients, with FOLFOX and FOLFIRI showing higher efficacy in 26 and 15 patients, respectively, and equal efficacy in 2 cases. This method has the potential to facilitate the establishment of individualized first-line chemotherapy for CRC and improve the prognosis in such patients.

Good response to leucovorin and fluorouracil plus oxaliplatin and cetuximab therapy in a patient with metastatic ascending colon cancer harboring a KRAS p.G13D mutation.

The effectiveness of cetuximab (Cmab) against KRAS p.G13D mutant-type tumors has been reported. In this study, we report a case of metastatic ascending colon cancer harboring a KRAS p.G13D mutation in a 65-year-old female. Considering the absence of symptoms and the post-operative risk of respiratory system complications due to multiple lung metastases, particularly at the entrance to the left main bronchus, anticancer drug therapy was selected as first-line therapy. With informed consent, FOLFOX4 [folinic acid (FOL), fluorouracil (F) plus oxaliplatin (OX)] + Cmab therapy was administered as preoperative chemotherapy. A good preoperative response was obtained to the chemotherapy, with a metastatic lesion disappearing from the entrance to the left main bronchus. Subsequent resection was performed successfully with no post-operative complications. Although a histopathological examination of the resected tissue specimen revealed residual cancer cells, it also showed the marked efficacy of the chemotherapy regimen used. In this study, we describe a case of metastatic ascending colon cancer harboring a KRAS p.G13D mutation in which the patient responded well to first-line therapy with FOLFOX4 + Cmab.

Identification of responders/non-responders to 5-fluorouracil based on individual 50% inhibitory area under the concentration curve of 5-fluorouracil obtained with collagen gel droplet-embedded culture-drug sensitivity test in colorectal cancer.

We previously reported the 5-fluorouracil (5-FU) sensitivity of cancer cells obtained from colorectal cancer (CRC) patients using the collagen gel droplet-embedded culture-drug sensitivity test (CD-DST). Multiple drug concentrations and contact durations, and the area under the concentration curve (AUC) and growth inhibition rate (IR) were combined, resulting in the AUC-IR curve, which was approximated to the logarithmic curve. Moreover, the individualized AUC(IR50), the AUC value which gives 50% growth inhibition, was calculated using the AUC-IR curve. This study aimed to identify responders/non-responders to 5-FU based on the individual AUC(IR50) obtained with CD-DST in order to establish individualized chemotherapy for CRC patients. The individual AUC(IR50) was calculated from each AUC-inhibition rate regression curve in all patients using the CD-DST. The cumulative distribution of the individual AUC(IR50) in CRC patients was evaluated. The cumulative distribution of the individual AUC(IR50) was regressed over the sigmoid curve (logarithmic scale). The approximate expression was almost exactly y=ab^exp(-cx) (a=0.9739, b=1.7096E-21, c=0.8990, the sum of square residuals, 0.0279). In the 80 cases examined, no notable change was observed in the regression curve when the number of patients increased. A standard curve was obtained describing responders to 5-FU among all CRC patients. From this standard curve, we ascertained that non-responders accounted for approximately 5% of all patients. Moreover, we were able to classify responders into good or intermediate responders to 5-FU. The standard curve describing response to 5-FU in CRC patients offers a useful tool in the establishment of individualized chemotherapy.