Takumi Ochiai

Prognostic impact of orotate phosphoribosyl transferase among 5‐fluorouracil metabolic enzymes in resectable colorectal cancers treated by oral 5‐fluorouracil‐based adjuvant chemotherapy

Orotate phosphoribosyl transferase (OPRT) is the main enzyme that involves in phosphoribosylation of 5‐fluorouracil (5‐FU), an essential step that leads to tumor growth inhibition. In our study, the prognostic relevance of OPRT, thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) in resectable colorectal cancer (CRC) patients treated by oral 5‐FU were compared to further clarify the prognostic value of OPRT. Tumor tissue was collected from 90 CRC patients and the patients were followed for 5.2 years (Median). TS, DPD and OPRT activities in the extract of tumor tissue were determined enzymatically. The cut‐off value of OPRT (0.147 nmol/(min mg), TS (0.044 pmol/mg) and DPD (72.10 pmol/(min mg) were determined by maximal χ2 method. Among these 5‐FU metabolic enzymes, only high OPRT group demonstrated significantly better disease‐free survival (DFS) (p = 0.0152) and better overall survival (p = 0.0078). In Cox regression analysis, node status (p < 0.0005) and OPRT (p = 0.044) were significant factors for DFS. OPRT activity in tumor tissue was a predictor of prognosis in resectable CRC patients treated by oral 5‐FU‐based adjuvant chemotherapy, and was useful to pick‐up high risk patients independent from known prognosis factors.

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.

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.

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.

Prognostic impact of orotate phosphoribosyl transferase (OPRT) activity in resectable colorectal cancers (CRC) treated by 5-FU-based adjuvant chemotherapy

3574 Background: Dihydropyrimidine dehydrogenase and thymidylate synthase are 5-FU metabolism and target enzyme, and has been studied as prognostic factors in CRC. Meanwhile, phosphoribosylation of 5-FU is an essential step leads to tumor growth inhibition and OPRT is the main enzyme that involves in this conversion of 5-FU to FUMP. The aim of this study was to evaluate the prognostic relevance of OPRT activity in CRC patients treated by 5-FU-based adjuvant chemotherapy. METHODS Surgical specimen was obtained from resectable CRC patients who were subsequently treated by 5-FU-based adjuvant chemotherapy. OPRT activity in the extract of tumor tissue was determined by the method of Laskin et al. Disease-free survival (DFS) and overall survival (OS) were calculated using Kaplan-Meier estimate. RESULTS During 1999 to 2003, tumor tissue was collected from 124 CRC patients and then the patients were followed for 3.7 years (Median). Patients were divided into 2 groups by the cut-off value of tumor OPRT (0.147 nmol/min/mg protein) determined by maximal χ2 method (high group (≥0.147): n=102, low group (<0.147): n=22). There were no significant imbalances in T and N value between 2 groups. 5-year DFS for high and low group were 75.7% and 56.9% (p=0.05, log-rank test) and OS were 84.6% and 58.4% (p=0.01), respectively. CONCLUSIONS Lower OPRT activity in tumor tissue was associated with poor survival in resectable CRC patients treated by 5-FU-based adjuvant chemotherapy and this research clarified that OPRT assay is indispensable for the determination of 5-FU-based adjuvant chemotherapy indication. Thus, the application of OPRT assay to routine clinical practice should be considered prior to 5-FU-based adjuvant chemotherapy. No significant financial relationships to disclose.

A CASE OF TYPHOID ULCERS FOLLOWED UP WITH COLONOSCOPY

A 56‐year‐old man was admitted to the Misato‐Junshin Hospital because of severe melena, fever, and abdominal pain. He had never traveled outside of Japan. Colonoscopic examinations revealed multiple round ulcers extending from the cecum to the proximal transverse colon. Cultures of stools and arterial blood were positive for Salmonella typhi, confirming a diagnosis of typhoid fever. The patient responded to treatment with oral neuquinoron antibiotics, tosufloxacin tosilate.

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.

Personalized adjuvant chemotherapy for colorectal cancer based on an individual 50% inhibitory area under the concentration curve using collagen gel droplet embedded culture-drug sensitivity test.

3582 Background: Tumor cell drug sensitivity is important in developing personalized chemotherapy. We approximated growth inhibition rate (IR) and area under the concentration curve (AUC) of 5-FU t...

Usefulness of the Perineum Pusher in Performing Rectal Procedures

We invented the Perineum Pusher to prevent excessive extension of the rectum by elevating the bottom of the pelvis. In the treatment of cancers of the middle and lower thirds of the rectum, a clear operative view can be maintained for a long time by using the Perineum Pusher. Consequently, a sphincter-saving rectal resection with coloanal anastomosis can be performed easily and safely. In addition, intraoperative rectal irrigation can be performed using the Perineum Pusher. No complications resulting from the Perineum Pusher have been experienced in 27 rectal cancer patients. As the Perineum Pusher can be used very simply and effectively in sphincter-saving rectal resections with coloanal anastomosis, this new surgical instrument is therefore highly recommended for use when performing various rectal procedures.

Acute Gastric Mucosal Injury Caused by Ingestion of Chlorinated Fungicide

We encountered a patient with acute gastric mucosal injury caused by ingestion of a chlorinated fungicide. Approximately 15 h after the episode of ingestion, endoscopic views were compatible with the acute gastric mucosal lesion of severe degree throughout the stomach. At that time, endoscopic biopsy showed congestion in the epithelial layer of the mucosa, along with lymphocytic infiltration that had likely existed from the onset of the condition. On the third day, the mucosal lesion looked more serious with peculiar hemorrhagic folds, and biopsy revealed exfoliation of the epithelial surface and neutrophilic infiltration in the stroma of the epithelial layer. On the seventh day, endoscopic images showed persistence of the lesion, but biopsy demonstrated the development of regenerating epithelium along with a marked reduction in infiltration of neutrophils and edema in the stroma.