Liver collagen in cirrhosis correlates with portal hypertension and liver dysfunction.

Liver collagen proportionate area (CPA) assessed by computer-assisted digital image analysis has been proposed as an accurate and objective histological variable for subclassifying cirrhosis. The study aimed to examine the relationship between CPA and relevant clinical parameters in cirrhotic patients and to evaluate the sampling variability for CPA. The study included 48 consecutive liver transplantation patients with established cirrhosis. Hepatic venous pressure gradient (HVPG) and serum markers of liver failure were determined prior to transplantation. CPA was assessed in the explanted livers. In 20 of the livers, CPA was measured in more than one tissue sample. CPA showed significant correlations with HVPG and with various surrogate markers of hepatic dysfunction including albumin, bilirubin, INR, MELD score and Child-Pugh score. CPA reliably discriminated HVPG ≥10 mmHg, termed 'clinically significant portal hypertension' (area under receiver operator curve: 0.923, p < 0.001; odds ratio: 1.209, p = 0.003). CPA measured on tissue blocks showed no significant sampling variability (p > 0.5). In conclusion, the study correlated portal hypertension and hepatic dysfunction with the amount of collagen in cirrhotic livers. The findings support the presumption of CPA as a useful histological marker for subclassifying cirrhosis and as a helpful supplement to the qualitative description of hepatic architectural changes in routine pathology.

The association of polymorphisms in 5-fluorouracil metabolism genes with outcome in adjuvant treatment of colorectal cancer.

AIM: The purpose of this study was to investigate whether specific combinations of polymorphisms in 5-fluorouracil (5-FU) metabolism-related genes were associated with outcome in 5-FU-based adjuvant treatment of colorectal cancer. METHODS: We analyzed two cohorts of 302 and 290 patients, respectively, one cohort for exploratory analyses and another cohort for validating the exploratory analyses. A total of ten polymorphisms in genes involved in 5-FU pharmacodynamics and pharmacokinetics were studied. End points were disease-free survival (DFS) and overall survival. Multifactor dimensionality reduction was used to identify genetic interaction profiles associated with outcome. RESULTS: Low-expression alleles in thymidylate synthase (TYMS) were associated with decreased DFS and overall survival (DFS:hazard ratio [HR] exploration 2.65 [1.40-4.65]; p = 0.004, HR validation 1.69 [1.03-2.66]; p = 0.03). A specific multifactor dimensionality reduction derived combination of dihydropyrimidine dehydrogenase and TYMS polymorphisms was associated with increased DFS (HR exploration 0.69 [0.49-0.98]; p = 0.04, HR validation 0.66 [0.45-0.95]; p = 0.03). Specific combinations of functional polymorphisms in DPYD and TYMS were demonstrated to be associated with DFS and overall survival in patients receiving adjuvant 5-FU-based treatment. Specifically high TYMS expression alleles seem to be associated with decreased DFS.

Combinations of polymorphisms in genes involved in the 5-Fluorouracil metabolism pathway are associated with gastrointestinal toxicity in chemotherapy-treated colorectal cancer patients.

PURPOSE: The purpose of this study was to investigate whether specific combinations of polymorphisms in genes encoding proteins involved in 5-fluorouracil (5-FU) pharmacokinetics and pharmacodynamics are associated with increased risk of treatment-induced toxicity. EXPERIMENTAL DESIGN: We analyzed two cohorts of 161 and 340 patients, the exploration and validation cohort, respectively. All patients were treated similarly with 5-FU-based adjuvant chemotherapy. We analyzed 13 functional polymorphisms and applied a four-fold analysis strategy using individual polymorphisms, haplotypes, and phenotypic enzyme activity or expression classifications based on combinations of functional polymorphisms in specific genes. Furthermore, multifactor dimensionality reduction analysis was used to identify a genetic interaction profile indicating an increased risk of toxicity. RESULTS: Alleles associated with low activity of methylene tetrahydrofolate reductase (MTHFR) were associated with decreased risk of toxicity [OR(Exploration) 0.39 (95% CI: 0.21-0.71, P = 0.003), OR(Validation) 0.63 (95% CI: 0.41-0.95, P = 0.03)]. A specific combination of the MTHFR 1298A>C and thymidylate synthase (TYMS) 3'-UTR (untranslated region) ins/del polymorphisms was significantly associated with increased toxicity in both cohorts [OR(Exploration) 2.40 (95% CI: 1.33-4.29, P = 0.003), OR(Validation) 1.81 (95% CI: 1.18-2.79, P = 0.007)]. The specific combination was also associated with increased cumulative incidence and earlier occurrence of severe toxicity during treatment. CONCLUSIONS: Our results indicate that MTHFR activity and a specific combination of the MTHFR 1298A>C and TYMS 3'-UTR ins/del polymorphisms are possible predictors of 5-FU treatment-related toxicity.

Microsatellite instability in colorectal cancer and association with thymidylate synthase and dihydropyrimidine dehydrogenase expression.

BACKGROUND: Microsatellite instability (MSI) refers to mutations in short motifs of tandemly repeated nucleotides resulting from replication errors and deficient mismatch repair (MMR). Colorectal cancer with MSI has characteristic biology and chemosensitivity, however the molecular basis remains unclarified. The association of MSI and MMR status with outcome and with thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) expression in colorectal cancer were evaluated. METHODS: MSI in five reference loci, MMR enzymes (hMSH2, hMSH6, hMLH1 and hPMS2), thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) expression were assessed in paraffin embedded tumor specimens, and associated with outcome in 340 consecutive patients completely resected for colorectal cancer stages II-IV and subsequently receiving adjuvant 5-fluorouracil therapy. RESULTS: MSI was found in 43 (13.8%) tumors. Absence of repair protein expression was assessed in 52 (17.0%) tumors, which had primarily lost hMLH1 in 39 (12.7%), hMSH2 in 5 (1.6%), and hMSH6 in 8 (2.6%) tumors. In multivariate analysis MSI (instable) compared to MSS (stable) tumors were significantly associated with lower risk of recurrence (hazard ratio (HR) = 0.3; 95% CI: 0.2-0.7; P = 0.0007) and death (HR = 0.4; 95% CI: 0.2-0.9; P = 0.02) independently of the TS and DPD expressions. A direct relationship between MSI and TS intensity (P = 0.001) was found, while there was no significant association with DPD intensity (P = 0.1). CONCLUSION: The favourable outcome of MSI colorectal carcinomas is ascribed mainly to the tumor biology and to a lesser extent to antitumor response to 5-fluorouracil therapy. There is no evidence that differential TS or DPD expression may account for these outcome characteristics.

Prognostic significance of numeric aberrations of genes for thymidylate synthase, thymidine phosphorylase and dihydrofolate reductase in colorectal cancer.

BACKGROUND: Most human cancer cells have structural aberrations of chromosomal regions leading to loss or gain of gene specific alleles. This study aimed to assess the range of gene copies per nucleus of thymidylate synthase (TYMS), thymidine phosphorylase (TP) and dihydrofolate reductase (DHFR) in colorectal cancer, and to evaluate its prognostic significance following adjuvant chemotherapy, since these enzymes are closely related to efficacy of 5-fluorouracil (5FU). PATIENTS AND METHODS: Consecutive patients (n = 314), who were completely resected for colorectal cancer stages II-IV and adjuvantly treated with 5-FU were retrospectively evaluated. Paraffin embedded tumor specimens were assessed for gene copies per nucleus of TYMS, TP and DHFR by fluorescence in situ hybridisation (FISH) using specific peptide nucleic acid probes. Outcome according to gene copies per nucleus above and below the median were compared. Also TYMS expression, assessed by immunohistochemistry, was associated with TYMS copies per nucleus. RESULTS: The number of gene copies per nucleus were 1.7 (0.7-2.8), 1.8 (0.9-3.1) and 1.8 (1.1-2.7) median (range) for TYMS, TP and DHFR, respectively. TYMS expression was directly associated with TYMS genes per nucleus (p = 0.05). Cox multivariate analysis, adjusted for the prognostic impact of disease stage, vascular tumor invasion, and bowel obstruction at resection, revealed that high TYMS gene copy number was associated with significantly higher risk of recurrence (HR = 1.6; 95%CI 1.1-2.2; p = 0.02) and death (HR = 1.6; 95%CI 1.1-2.3; p = 0.01). No significant differences in outcome appeared according to TP and DHFR gene ratios. CONCLUSION: Aberration of TYMS gene is of significance to expression of TYMS, which may influence the biology and 5-FU sensitivity of colorectal cancer. This may be utilized in the allocation of patients for treatment approaches and for decision on follow-up programs.

The prognostic significance of thymidylate synthase and dihydropyrimidine dehydrogenase in colorectal cancer of 303 patients adjuvantly treated with 5-fluorouracil.

Cytotoxic effect of 5-fluorouracil 5-FU is mediated through inhibition of thymidylate synthase (TS), and 5-FU is catabolised by dihydropyrimidine dehydrogenase (DPD). Efficacy of 5-FU may therefore depend on the TS and DPD activity of colorectal cancer. Archival tumour specimens from 303 consecutive patients were analysed for the expression of TS and DPD using immunohistochemistry. All patients were completely resected for colorectal cancer stages II-III and have subsequently received adjuvant treatment with 5-FU. In a multivariate analysis adjusting for the impact of bowel obstruction and vascular tumour invasion, diffuse TS pattern was significantly associated with increased risk of recurrence (hazard ratio (HR) = 1.9; 95% confidence interval (CI): 1.1-3.2; p = 0.02), but without significant association to death (HR = 1.6; 95% CI: 0.9-2.8; p = 0.08). High TS intensity was not significantly associated with lower risk of recurrence (HR = 0.6; 95% CI: 0.3-1.1; p = 0.07) or death (HR = 0.6; 95% CI: 0.3-1.2; p = 0.2). High DPD intensity was significantly associated with increased risk of recurrence (HR = 1.5; 95% CI: 1.1-2.3; p = 0.03) and death (HR = 1.6; 95% CI: 1.1-2.5; p = 0.02). Patients with a combination of low TS and high DPD intensity were at significantly increased risk of both recurrence (HR = 2.1; 95% CI: 1.0-4.2; p = 0.04) and death (HR = 2.0; 95% CI: 1.0-4.0; p = 0.05). No relationship between tolerability and toxicity of 5-FU and TS and DPD expression was found. It is concluded that characterizing colorectal carcinomas by TS and DPD expression may disclose subsets of patients with significantly greater risk of disease recurrence and early death. This may be utilized in the selection of patients for treatment approaches and for decision on follow-up programs.