Proteomic profiling of tumour tissue-derived extracellular vesicles in colon cancer.

Colon cancer is one of the most commonly occurring tumours among both women and men, and over the past decades the incidence has been on the rise. As such, the need for biomarker identification as well as an understanding of the underlying disease mechanism has never been greater. Extracellular vesicles are integral mediators of cell-to-cell communication and offer a unique opportunity to study the machinery that drives disease progression, and they also function as vectors for potential biomarkers. Tumour tissue and healthy mucosal tissue from the colons of ten patients were used to isolate tissue-resident EVs that were subsequently subjected to global quantitative proteomic analysis through LC-MS/MS. In total, more than 2000 proteins were identified, with most of the common EV markers being among them. Bioinformatics revealed a clear underrepresentation of proteins involved in energy production and cellular adhesion in tumour EVs, while proteins involved in protein biosynthesis were overrepresented. Additionally, 53 membrane proteins were found to be significantly upregulated in tumour EVs. Among them were several proteins with enzymatic functions that degrade the extracellular matrix, and three of these, Fibroblast activating factor (FAP), Cell surface hyaluronidase (CEMIP2), as well as Ephrin receptor B3 (EPHB3), were validated and found to be consistent with the global quantitative results. These stark differences in the proteomes between healthy and cancerous tissue emphasise the importance of the interstitial vesicle secretome as a major player of disease development.

The Resection Rate of Synchronously Detected Liver and Lung Metastasis from Colorectal Cancer Is Low-A National Registry-Based Study.

Population-based data on the incidence and surgical treatment of patients with colorectal cancer (CRC) and synchronous liver and lung metastases are lacking as are real-life data on the frequency of metastasectomy for both sites and outcomes in this setting. This is a nationwide population-based study of all patients having liver and lung metastases diagnosed within 6 months of CRC between 2008 and 2016 in Sweden identified through the merging of data from the National Quality Registries on CRC, liver and thoracic surgery and the National Patient Registry. Among 60,734 patients diagnosed with CRC, 1923 (3.2%) had synchronous liver and lung metastases, of which 44 patients had complete metastasectomy. Surgery of liver and lung metastases yielded a 5-year OS of 74% (95% CI 57-85%) compared to 29% (95% CI 19-40%) if liver metastases were resected but not the lung metastases and 2.6% (95% CI 1.5-4%) if non-resected, p < 0.001. Complete resection rates ranged from 0.7% to 3.8% between the six healthcare regions of Sweden, p = 0.007. Synchronous liver and lung CRC metastases are rare, and a minority undergo the resection of both metastatic sites but with excellent survival. The reasons for differences in regional treatment approaches and the potential of increased resection rates should be studied further.

SOULMATE: the Swedish study of liver transplantation for isolated colorectal cancer liver metastases not suitable for operation or ablation, compared to best established treatment-a randomized controlled multicenter trial.

BACKGROUND: Around one fourth of patients with colorectal cancer present themselves with distant metastases at the time of diagnosis, and one additional one fifth of the patients will develop distant metastases during the disease, most commonly in the liver. Surgical treatment such as liver resection or ablation, often combined with chemotherapy and targeted therapy, is the only treatment option with curative potential, but only about 20% of the patients with liver metastases are candidates for surgical intervention. Standard treatment for unresectable patients is palliative oncological therapy; however, less than 10% of these patients will achieve a 5-year survival. Non-randomized studies indicate that liver transplantation could be an option for selected patients with colorectal liver metastases (CRLM), which are not suitable for operation or ablation due to surgical technical reasons such as massive tumor burden and small future liver remnant, or oncological reasons, for example, early relapse after liver surgery. Since there is a shortage of donated liver grafts, it is important to select the patient group that benefit most from the treatment. Although some studies present positive results from liver transplantation of CRLM, the results must be validated in a randomized controlled trial before this new indication for liver transplantation can be introduced as a clinical routine. METHODS: The SOULMATE study is a randomized study evaluating if liver transplantation with liver grafts, primarily from extended criteria donors, increases overall survival in patients with CRLM, not suitable for resection or ablation, in comparison with best established treatment. Patients will be randomized to liver transplantation (LT)+ best established treatment (BET) or to best established treatment only. In the SOULMATE trial, we will evaluate the use of livers from extended criteria donors to decrease the risk of prolonging waiting time for patients on the waiting list for LT. DISCUSSION: The SOULMATE study has the possibility to confirm the positive results of previous studies in a randomized setting. The use of extended criteria donors will make the results transferable globally, as most countries are struggling with organ shortage. TRIAL REGISTRATION: Clinical Trial number: NCT04161092 registered 13 November 2019.

Prolonged postoperative length of stay may be a valuable marker for susceptibility to relapse beyond established risk factors in patients with stage III colon cancer.

BACKGROUND: Delay from surgery to adjuvant chemotherapy causes impaired survival among patients undergoing radical resection for stage III colon cancer, and the underlying mechanism for this is incompletely clarified. It is established that prolonged postoperative hospital length of stay (LOS) is associated with delayed initiation of the adjuvant treatment driving the assumption that prolonged LOS is prognostically unfavorable due to this fact and case mix factors. We hypothesize that prolonged LOS after surgery is a valuable marker for susceptibility to relapse that is not detected in established prognostic factors and, alone, associated with a shorter disease-free survival (DFS). MATERIALS AND METHODS: A total of 690 consecutive patients undergoing elective radical resection for stage III colon cancer in 2000-2015 were identified in a prospective detailed facility database. Univariate and multivariate analyses were performed using Cox proportional hazards model in the evaluation of LOS as an independent prognostic factor. RESULTS: Short postoperative LOS, low comorbidity, and few complications were associated with longer DFS (p < 0.01). Fewer patients in the short and intermediate LOS groups had a relapse in their disease (28% and 33%, respectively), compared to the patients with longer LOS (40%, p < 0.05). LOS was a prognostic factor for DFS in the unadjusted univariate model (HR 1.04 per unit change) and remained statistically significant in the adjusted multivariate analysis, with a HR of 1.03 per hospital day (p < 0.01). CONCLUSIONS: Postoperative LOS independently correlates with the risk of recurrence and DFS, regardless of if adjuvant chemotherapy is given, along with the factors such as age, comorbidity, complications, and tumor features. We propose a further investigation into the causal mechanisms based on tumor and host biology linking LOS to DFS beyond established risk factors.

A Fraction of CD8+ T Cells from Colorectal Liver Metastases Preferentially Repopulate Autologous Patient-Derived Xenograft Tumors as Tissue-Resident Memory T Cells.

The diversity of T cells in the human liver may reflect the composition of TILs in CRLM. Our ex vivo characterization of CRLM vs. adjacent liver tissue detected CD103+CD39+CD8+ TRM cells predominantly in CRLM, which prompted further assessments. These TRM cells responded to cognate antigens in vitro. As functional activities of autologous TILs are central to the implementation of personalized cancer treatments, we applied a patient-derived xenograft (PDX) model to monitor TILs' capacity to control CRLM-derived tumors in vivo. We established PDX mice with CRLMs from two patients, and in vitro expansion of their respective TILs resulted in opposing CD4+ vs. CD8+ TIL ratios. These CRLMs also displayed mutated KRAS, which enabled trametinib-mediated inhibition of MEK. Regardless of the TIL subset ratio, persistent or transient control of CRLM-derived tumors of limited size by the transferred TILs was observed only after trametinib treatment. Of note, a portion of transferred TILs was observed as CD103+CD8+ TRM cells that strictly accumulated within the autologous CRLM-derived tumor rather than in the spleen or blood. Thus, the predominance of CD103+CD39+CD8+ TRM cells in CRLM relative to the adjacent liver and the propensity of CD103+CD8+ TRM cells to repopulate the autologous tumor may identify these TILs as strategic targets for therapies against advanced CRC.

Increasing Dosage of Leucovorin Results in Pharmacokinetic and Gene Expression Differences When Administered as Two-Hour Infusion or Bolus Injection to Patients with Colon Cancer.

The combination of 5-fluorouracil (5-FU) and leucovorin (LV) forms the chemotherapy backbone for patients with colorectal cancer. However, the LV administration is often standardized and not based on robust scientific data. To address these issues, a randomized pharmacokinetics study was performed in patients with colon cancer. Thirty patients were enrolled, receiving 60, 200 or 500 mg/m2 LV as a single two-hour infusion. Blood, tumor, mucosa, and resection margin biopsies were collected. Folate concentrations were analyzed with LC-MS/MS and gene expression with qPCR. Data from a previous study where patients received LV as bolus injections were used as comparison. Saturation of methylenetetrahydrofolate (MeTHF) and tetrahydrofolate (THF) levels was seen after two-hour infusion and polyglutamated MeTHF + THF levels in tumors decreased with increasing LV dosage. The decrease was associated with decreased FPGS and increased GGH expression, which was not observed after LV bolus injection. In the bolus group, results indicate activation of a metabolic switch possibly promoting TYMS inhibition in response to 5-FU. Different metabolic mechanisms appear to be induced when LV is administered as infusion and bolus injection. Since maximal inhibition of TYMS by the 5-FU metabolite 5-fluoro-2'-deoxyuridine 5'-monophosphate (FdUMP) requires excess polyglutamated MeTHF, the results point in favor of the bolus regimen.

Aspirin as secondary prevention in colorectal cancer liver metastasis (ASAC trial): study protocol for a multicentre randomized placebo-controlled trial.

BACKGROUND: Colorectal cancer is one the most common cancers in the western world with increasing incidence. Approximately 50% of the patients develop liver metastases. Resection of liver metastases is the treatment of choice although almost half of the resected patients get recurrence in the liver. METHODS: The ASAC trial is a Scandinavian, multicentre, double-blinded, randomized, placebo-controlled study to determine whether adjuvant treatment with low-dose aspirin (acetylsalicylic acid (ASA)) can improve disease-free survival in patients treated for colorectal cancer liver metastases (CRCLM). Up to 800 patients operated for CRCLM will be randomized to Arm#1 ASA 160 mg once daily or Arm#2 Placebo, for a period of 3 years or until disease recurrence. The patients will be recruited at all major hepatobiliary surgical units in Norway, Sweden and Denmark and have follow-up according to standard of care and the National Guidelines. DISCUSSION: The ASAC trial will be the first clinical interventional trial to assess the potential beneficial role of ASA in recurrence of CRCLM and survival. ASA is an inexpensive, well-tolerated and easily accessible drug that will be highly potential as adjuvant drug in secondary prevention of CRCLM if the study shows a beneficial effect. We will also determine the effect of ASA as adjuvant treatment on Health-Related Quality of Life and the cost-effectiveness. TRIAL REGISTRATION: ClinicalTrials.gov NCT03326791 . Registered on 31 October 2017.

Pharmacokinetics of preoperative intraperitoneal 5-FU in patients with pancreatic ductal adenocarcinoma.

PURPOSE: The aim was to investigate the pharmacokinetics of preoperatively administered intraperitoneal (IP) 5-FU in patients with resectable pancreatic ductal adenocarcinoma (PDAC) by analyzing levels of 5-FU and target metabolites in peritoneal fluid, plasma, liver, lymph nodes, pancreatic tumour, and pancreatic tissue. These results were correlated to expression of genes encoding enzymes of the 5-FU pathway and cell membrane transporters of 5-FU and FdUMP. METHODS: Twenty-two patients with PDAC were treated with IP 5-FU before surgery. The postoperative treatment followed a routine clinical protocol. 5-FU and its metabolites were analyzed by LC-MS/MS. The expression of genes encoding enzymes and transporters in the 5-FU pathway was analyzed by qPCR. RESULTS: After IP treatment, 5-FU could be detected in plasma, lymph nodes, liver, pancreatic tumour, and pancreatic tissue. The highest 5-FU concentration was found in the liver, also expressing high levels of the 5-FU transporter OAT2. 5-FU was converted to active FdUMP in all tissues and the highest concentration was measured in lymph nodes, liver and pancreatic tumour (18.5, 6.1 and 6.7 pmol/g, respectively). There was a correlation between the FdUMP and dUr levels in lymph nodes (r = 0.70, p = 0.0076). In tumours, there was an association between OAT2 expression and FdUMP concentration. CONCLUSION: The study shows uptake of IP 5-FU and drug metabolism to active FdUMP in pancreatic tumour, liver, and lymph nodes. Extended studies are warranted to evaluate the IP route for 5-FU administration in PDAC patients.

Plasma deoxyuridine as a surrogate marker for toxicity and early clinical response in patients with metastatic colorectal cancer after 5-FU-based therapy in combination with arfolitixorin.

PURPOSE: The aim was to explore the correlation between increasing doses of [6R]-5,10-methylenetetrahydrofolate (arfolitixorin) and plasma concentrations of deoxyuridine (dUr) in patients with metastatic colorectal cancer (mCRC), subjected to 5-fluorouracil (5-FU)-based chemotherapy. The aim was further to investigate the possibility to predict toxicity and clinical response during treatment using gender, age, and plasma dUr as explanatory variables. METHODS: Thirty-three patients from the ISO-CC-005 phase I/IIa study, which investigated safety and tolerability of arfolitixorin at four dose levels, were included. Toxicity and clinical response were evaluated after 4 cycles of chemotherapy. Plasma dUr was quantified before (0 h) and 24 h after 5-FU administration at the first (C1) and fourth (C4) cycle using LC-MS/MS. Fit modelling was used to predict toxicity and clinical response. RESULTS: The dUr levels increased with increasing arfolitixorin dose. Females had higher total and haematological toxicity scores (p = 0.0004 and 0.0089, respectively), and needed dose reduction more often than males (p = 0.012). Fit modeling showed that gender and the dUr levels at C1-0 h and C4-24 h predicted total toxicity (p = 0.0011), whereas dUr C4-0 h alone was associated with gastrointestinal toxicity (p = 0.026). Haematological toxicity was predicted by gender and age (p = 0.0071). The haematological toxicity score in combination with the dUr levels at C1-24 h and C4-24 h predicted early clinical response (p = 0.018). CONCLUSION: The dUr level before and during administration of 5-FU and arfolitixorin was predictive for toxicity and early clinical response and could be a potential surrogate marker for thymidylate synthase inhibition in patients with mCRC. TRIAL REGISTRATION: NCT02244632, first posted on ClinicalTrials.gov on September 19, 2014.

Quality-of-life after bile duct injury repaired by hepaticojejunostomy: a national cohort study.

OBJECTIVES: Reports on quality-of-life (QoL) after bile duct injury (BDI) show conflicting results. The aim of this cohort study was to evaluate QoL stratified according to type of treatment. METHODS: QoL assessment using the SF-36 (36-item short form health survey) questionnaire. Patients with post-cholecystectomy BDI needing hepaticojejunostomy (HJ) were compared to all other treatments (BDI repair) and to patients without BDI at cholecystectomy (controls). RESULTS: Patients needing a HJ after BDI reported reduced long-term QoL irrespective of time for diagnosis and repair in both the physical (PCS; p < .001) and mental (MCS; p < .001) domain compared to both controls and patients with less severe BDI. QoL was comparable for BDI repair (n = 86) and controls (n = 192) in both PCS (p = .171) and MCS (p = .654). As a group, patients with BDI (n = 155) reported worse QoL than controls, in both the PCS (p < .001) and MCS (p = .012). Patients with a BDI detected intraoperatively (n = 124) reported better QoL than patients with a postoperative diagnosis. Patients with an immediate intraoperative repair (n = 99), including HJ, reported a better long-term QoL compared to patients subjected to a later procedure (n = 54). CONCLUSIONS: Patients with postoperative diagnosis and patients with BDIs needing biliary reconstruction with HJ both reported reduced long-term QoL.

Surgical treatment of breast cancer liver metastases - A nationwide registry-based case control study.

INTRODUCTION: The benefit of liver resection or ablation for breast cancer liver metastases (BCLM) remains unclear. The aim of the study was to determine survival after isolated BCLM in nationwide cohorts and compare surgical versus systemic treatment regimens. MATERIALS AND METHODS: The Swedish register for cancer in the liver and the bile ducts (SweLiv) and the National register for breast cancer (NBCR) was studied to identify patients with 1-5 BCLM without extrahepatic spread diagnosed 2009-2016. Data from the registers were validated and completed by review of medical records. A Kaplan-Meier plot and log rank test were used to analyse survival. Prognostic and predictive factors were evaluated by Cox regression analysis. RESULTS: A surgical cohort (n = 29) was identified and compared to a control cohort (n = 33) receiving systemic treatment only. There was no 90-day mortality after surgery. Median survival from BCLM diagnosis was 77 months (95% CI 41-113) in the surgical cohort and 28 months (95% CI 13-43) in the control cohort, (p = 0.004). There was a longer disease-free interval and more oestrogen receptor positive tumours in the surgical cohort. Surgery was a significant positive predictive factor in univariate analysis while a multivariable analysis resulted in HR 0.478 (CI 0.193-1.181, p = 0.110) for surgical treatment. CONCLUSION: Surgery for BCLM is safe and might provide a survival benefit in selected patients but prospective trials are warranted to avoid selection bias.

Relationship between folate concentration and expression of folate-associated genes in tissue and plasma after intraoperative administration of leucovorin in patients with colorectal cancer.

PURPOSE: The aim of study was to investigate the relationship between folate concentration and expression of folate-associated genes in tumour, mucosa and plasma of patients with colorectal cancer, after intraoperative administration of bolus leucovorin (LV). METHODS: Eighty patients were randomized into four groups to receive 0, 60, 200, or 500 mg/m2 LV, respectively. Tissue and plasma folate concentrations were assessed by LC-MS/MS. Gene expression of ABCC3/MRP3, FPGS, GGH, MTHFD1L, SLC46A1/PCFT, and SLC19A1/RFC-1 was determined using quantitative PCR. RESULTS: The folate concentration in tumour increased with increasing dosage of LV. Half of the patients treated with 60 mg/m2 did not reach a level above the levels of untreated patients. A significant correlation between folate concentration in tumour and mucosa was found in untreated patients, and in the group treated with 60 mg/m2 LV. The 5-MTHF/LV ratio correlated negatively with folate concentration in mucosa, whereas a positive correlation was found in tumour of patients who received 200 or 500 mg/m2 LV. A positive correlation was found between folate concentration and expression of all genes, except MTHFD1L, in patients who received LV. There was a negative correlation between 5-MTHF concentration in plasma of untreated patients and expression of GGH and SLC46A1/PCFT in tumour. CONCLUSIONS: The results indicate the possibility of using the individual plasma 5-MTHF/LV ratio after LV injection as a surrogate marker for tissue folate concentration. Expression of several folate-associated genes is associated with folate concentration in tissue and plasma and may become useful when predicting response to LV treatment.

Cell-free DNA levels and correlation to stage and outcome following treatment of locally advanced rectal cancer.

Accurate staging of rectal cancer remains essential for optimal patient selection for combined modality treatment, including radiotherapy, chemotherapy and surgery. We aimed at examining the correlation of cell free DNA with the pathologic stage and subsequent risk of recurrence for patients with locally advanced rectal cancer undergoing preoperative chemoradiation. We examined 75 patients with locally advanced rectal cancer receiving preoperative chemoradiation. Blood samples for translational use were drawn prior to rectal surgery. The level of cell free DNA was quantified by digital droplet PCR and expressed as copy number of beta 2 microglobulin. We found a median level of cell free DNA in the AJCC stages I-III of 3100, 8300, and 10,700 copies/mL respectively. For patients with 12 sampled lymph nodes or above, the median level of cell free DNA were 2400 copies/mL and 4400 copies/mL (p = 0.04) for node negative and node positive disease respectively. The median follow-up was 39 months and 11 recurrences were detected (15%). The median level for patients with recurrent disease was 13,000 copies/mL compared to 5200 copies/mL for non-recurrent patients (p = 0.08). We have demonstrated a correlation between the level of total cell free DNA and the pathologic stage and nodal involvement. Furthermore, we have found a trend towards a correlation with the risk of recurrence following resection of localized rectal cancer.

A pharmacokinetic and pharmacodynamic investigation of Modufolin® compared to Isovorin® after single dose intravenous administration to patients with colon cancer: a randomized study.

PURPOSE: Leucovorin is commonly used as folate supplement in 5-fluorouracil-based chemotherapy, but needs to be converted to active 5,10-methylenetetrahydrofolate (methyleneTHF) intracellularly. This provides for interindividual differences. MethyleneTHF has recently been developed into the stable, distributable drug, Modufolin®. The aim was to compare the concentration of folate metabolites in tumor, mucosa, and plasma of patients with colon cancer after administration of Modufolin® or Isovorin® (levo-leucovorin). METHODS: Thirty-two patients scheduled for colon resection were randomized to receive Modufolin® or Isovorin® at dosage of 60 or 200 mg/m². The study drug was given as one i.v. bolus injection after anesthesia. Plasma was collected for pharmacokinetic (PK) analysis before, during, and after surgery. Tissue biopsies were collected at surgery. Folate metabolites were analyzed by LC-MS/MS. RESULTS: MethyleneTHF and THF concentrations were significantly higher in mucosa (p < 0.01, both dosages) and tumors (p < 0.01, 200 mg/m²) after Modufolin® as compared to Isovorin® administration. The results correlated with PK observations. The Modufolin® to Isovorin® C(max) ratio for methyleneTHF was 113 at 200 mg/m² and 52 at 60 mg/m²; the AUC(last) ratios were 17 and 9, respectively. The THF plasma concentrations were also higher after Modufolin® administration (C(max) ratio 23, AUC(last) ratio 13 at 200 mg/m²; C(max) ratio 15, AUC(last) ratio 11 at 60 mg/m²). CONCLUSION: Modufolin® administration resulted in significantly higher methyleneTHF levels than Isovorin® and may potentially increase the efficacy of 5-fluorouracil-based chemotherapy. The results encourage further evaluation of Modufolin® as a substitute to Isovorin® including the potential clinical benefits.

Folate levels measured by LC-MS/MS in patients with colorectal cancer treated with different leucovorin dosages.

PURPOSE: Calcium folinate (leucovorin), which is converted in vivo into biologically active folate, enhances the potency of 5-fluorouracil (5-FU)-based chemotherapy in colorectal cancer. A common dosage of leucovorin in adjuvant and palliative settings is 60 mg/m(2). The aim was to determine the levels of tetrahydrofolate (THF), 5,10-methylenetetrahydrofolate (methyleneTHF), and 5-methyltetrahydrofolate (methylTHF) in tumour and mucosa of colorectal cancer patients who received different dosages of leucovorin intravenously at time of surgery. METHODS: Eighty patients scheduled for colorectal resection with indication of colorectal cancer were randomised into four groups to receive leucovorin at 0, 60, 200, or 500 mg/m(2), respectively. Blood samples were taken 10 and 30 min after leucovorin administration. Biopsy samples from tumour and mucosa were collected and snap-frozen at surgery. The levels of THF, methyleneTHF, and methylTHF in tumour and mucosa were assessed by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-MS/MS) and the results were related to clinical diagnosis and therapeutic regimens. RESULTS: The folate levels in tissue revealed extensive inter-individual variability. The mean methyleneTHF value for the four treatment groups were 880, 1,769, 3,024 and 3,723 pmol/gww. Only half of the patients who received 60 mg/m(2) leucovorin had higher levels of methyleneTHF in tumour than patients who received 0 mg/m(2) leucovorin. Rectal cancer patients had significantly lower levels of methyleneTHF compared with colon cancer patients. CONCLUSIONS: There was a large inter-patient variability of tissue folate levels in colorectal cancer patients after supplementation with leucovorin at standardised dosage. High leucovorin doses were needed to exceed baseline methyleneTHF values, especially in rectal cancer patients. The results indicate that the standardised leucovorin dose may be insufficient to attain the full antitumour effect of 5-FU. Further studies are needed to establish whether higher dosage yields a better treatment response.

Folate Levels and Polymorphisms in the Genes MTHFR, MTR, and TS in Colorectal Cancer.

AIM: The aim of the study was to explore and describe the effect of polymorphisms in folate-associated genes regarding the levels of different folate forms and their distribution in tumors and mucosa in patients with colorectal cancer. MATERIALS AND METHODS: Tumor and mucosa tissues from 53 patients with colorectal cancer were analyzed. The concentrations of tetrahydrofolate (THF), 5-methylTHF, and 5,10-methyleneTHF were measured by liquid chromatography-mass spectrometry. Genotyping of polymorphisms in the folate-associated genes methylenetetrahydrofolate reductase (MTHFR, C677T), methionine synthase (MTR, A2756G), and thymidylate synthase (TS, 5'-TSER 28 bp tandem repeat and 3'-TSUTR 6 bp deletion/insertion), were done by real-time polymerase chain reaction. Folate levels and distributions were determined in the total patient cohort and after subgrouping by genotypes. RESULTS: The total folate level, as well as the THF and 5,10-methyleneTHF levels, were significantly higher in the tumor compared with mucosa tissue (P = 0.030, 0.031, and 0.015, respectively). The individual variation in folate levels in both tumor and mucosa were larger than the variation found when the patients were subgrouped by the gene polymorphisms. No significant differences in the mean concentration of any folate in the mucosa or tumor tissue were found in relation to the analyzed polymorphisms. The percentage level of 5,10-methyleneTHF in tumors was highest in patients with the MTHFR 677 CC genotype, and lowest in patients with the TT genotype (P = 0.033). A significantly lower percentage level of the 5,10-methyleneTHF level was found in tumors of patients with the 5'-TSER 3R/3R genotype (P = 0.0031). CONCLUSION: A significant difference was found between the percentage level of 5,10-methyleneTHF in tumor tissues in relation to the MTHFR C677T and 5'-TSER 28 bp repeat polymorphisms. However, no differences were found in the actual tissue folate levels, or in their distribution, in relation to the polymorphisms in the MTHFR, MTR, or TS genes. These findings could be of importance for further research in the field by explaining some of the difficulties of obtaining reproducible and uniform results when using a few selected polymorphisms as predictive markers.

Gene polymorphisms MTHFRC677T and MTRA2756G as predictive factors in adjuvant chemotherapy for stage III colorectal cancer.

BACKGROUND: The aim of this study was to explore the effect in stage III colorectal cancer of functional gene polymorphisms methylenetetrahydrofolate reductase (MTHFR C677T) and methionine synthase (A2756G), in the folate metabolism on outcome and risk of toxicity for adjuvant chemotherapy. A secondary aim was to investigate any possible interdependency between the two genes. PATIENTS AND METHODS: one hundred and fifty randomly chosen patients with stage III colorectal cancer, treated with adjuvant chemotherapy, were genotyped by real-time PCR. Patient and treatment data were retrieved and assessed for demography, pathology, chemotherapy tolerability and survival after adjuvant therapy. The polymorphisms were studied separately and in combination to discover possible interactions. RESULTS: Patients with MTHFR 677 CC genotype carried lower risks of suffering from nausea (p=0.027), parasthesia (p=0.0042) and need for dose reduction (p=0.025). The CC genotype was also associated with better survival (p<0.034). There was interdependency with MTR A2756G. Patients with MTR AG/GG in combination with MTHFR CT/TT genotypes carried the highest risk of side-effects. CONCLUSION: Functional polymorphisms of MTHFR C677T and MTR A2756G can affect outcome and risk of toxicity during adjuvant chemotherapy in stage III colorectal cancer. Their possible interdependence brings attention to the function of folate metabolism overall regarding its association with 5-fluoruracil related toxicity. Our results could explain some of the difficulties of obtaining reproducible and uniform results when using single polymorphisms as predictive markers.

Tumour differentiation grade is associated with TNM staging and the risk of node metastasis in colorectal cancer.

AIM: The tumour differentiation grade has been shown by numerous multivariate analyses to be a stage-independent prognostic factor in colorectal cancer. The aim of this study was to explore the importance of differentiation grading for the staging of colorectal cancer and how it relates to the components of the TNM system. MATERIAL AND METHODS: The study was a retrospective single-centre analysis of all patients undergoing surgical resection for colorectal cancer during the period 2002-2007 (n = 1239). The clinical parameters and pathology data of overall stage, differentiation grade, local tumour (T)-stage and metastasis status (M-stage) were included as well as the lymph node count of both assessed and metastatic nodes. The differentiation grade was correlated with demography, overall stage and each component of the TNM staging system. The correlation between differentiation grade and N-stage was also explored for the separate T-stages. RESULTS: The tumour differentiation grade correlated significantly with the overall TNM stage (p < 0.0001). The grade significantly correlated with the T-stage and the risk of having lymph node metastasis (p < 0.0001). A high grade was associated with a higher positive lymph node count in stage III disease (p < 0.0002). For the T-stages, the risk of node metastasis was significantly linked to the tumour grade. A low grade (G1) T2 had a 17% risk of lymph node metastasis compared to a 44% risk for a high grade (G4) T2. CONCLUSION: Tumour differentiation is an important prognostic factor. It correlates significantly with the overall stage of the TNM system and also to each of its components. The risk of having lymph node metastasis for each T-stage also correlates with the tumour grade. The findings can be of importance in postoperative risk assessment or when considering local resection procedures like TEM.