Impact of deep brain stimulation on gait in Parkinson disease: A kinematic study.

BACKGROUND: The effect of Deep Brain Stimulation (DBS) on gait in Parkinson's Disease (PD) is poorly understood. Kinematic studies utilizing quantitative gait outcomes such as speed, cadence, and stride length have shown mixed results and were done mostly before and after acute DBS discontinuation. OBJECTIVE: To examine longitudinal changes in kinematic gait outcomes before and after DBS surgery. METHOD: We retrospectively assessed changes in quantitative gait outcomes via motion capture in 22 PD patients before and after subthalamic (STN) or globus pallidus internus (GPi) DBS, in on medication state. Associations between gait outcomes and clinical variables were also assessed. RESULT: Gait speed reduced from 110.7 ± 21.3 cm/s before surgery to 93.6 ± 24.9 after surgery (7.7 ± 2.9 months post-surgery, duration between assessments was 15.0 ± 3.8 months). Cadence, step length, stride length, and single support time reduced, while total support time, and initial double support time increased. Despite this, there was overall improvement in the Movement Disorder Society-Unified Parkinson Disease Rating Scale-Part III score "on medication/on stimulation" score (from 19.8 ± 10.7-13.9 ± 8.6). Change of gait speed was not related to changes in levodopa dosage, disease duration, unilateral vs bilateral stimulation, or target nucleus. CONCLUSION: Quantitative gait outcomes in on medication state worsened after chronic DBS therapy despite improvement in other clinical outcomes. Whether these changes reflect the effects of DBS as opposed to ongoing disease progression is unknown.

Clinicopathological features of peripheral odontogenic fibromas in dogs and risk factors for their laboratory diagnosis.

OBJECTIVES: To explore clinicopathological features of peripheral odontogenic fibromas in dogs and risk factors for their diagnosis. MATERIALS AND METHODS: Data of cases with a histopathological diagnosis of peripheral odontogenic fibromas were obtained from a UK-based diagnostic laboratory and retrospectively reviewed. Prevalence amongst all biopsy submissions was assessed using binomial tests and Clopper-Pearson intervals. Age at diagnosis was assessed using t-test for independent samples. Lesion location, sex, and neuter status were assessed using χ2 and post hoc binomial tests. Breed odds ratios were calculated using univariable logistic regression modelling. RESULTS: The prevalence of peripheral odontogenic fibromas amongst all biopsy submissions was 2.8% (1001 of 35,328, 95% confidence interval [CI]: 2.7 to 3.0). The mean (sd) age was 8.1 (±2.7) years. The most affected quadrant was the rostral maxilla (40.1%). The ratio of maxillary to mandibular lesions was 1.3:1 (95% CI: 1.1 to 1.5), and for cases of multiple peripheral odontogenic fibromas the ratio of maxillary to mandibular lesions was 2.4:1 (95% CI: 1.1 to 5.6). Males had 1.2 times the odds of suffering of peripheral odontogenic fibromas compared to females (odds ratio [OR]: 1.2, 95% CI: 1.1 to 1.4). Neutering was associated with an increased risk of diagnosis (OR: 1.6, 95% CI: 1.3 to 1.9). Breeds with increased odds of peripheral odontogenic fibromas compared to crossbreed dogs included boxers (OR: 3.78, 95% CI: 2.80 to 5.09), border terriers (OR: 3.21, 95% CI: 2.10 to 4.91) and Basset Hounds (OR: 3.18, 95% CI: 1.58 to 6.44). Breeds with increased odds of multiple simultaneous peripheral odontogenic fibromas compared to crossbreed dogs included: Boxers (OR: 12.02, 95% CI: 7.13 to 20.24), border terriers (OR: 5.05, 95% CI: 2.32 to 11.43) and Staffordshire Bull terriers (OR: 2.42, 95% CI: 1.33 to 4.41). CLINICAL SIGNIFICANCE: Knowledge of clinicopathological features and at-risk breeds for peripheral odontogenic fibroma development can assist clinicians with making a diagnosis. The identification of risk factors provides targets for future research investigating peripheral odontogenic fibroma pathogenesis.

Endoscopic extrasellar skull base reconstruction using bioabsorbable plates.

BACKGROUND: Many techniques have been utilized for reconstruction of the anterior skull base. Each method has advantages and disadvantages with respect to effectiveness, morbidity, strength, and cost. Rigid reconstruction may provide advantages in certain patients. OBJECTIVE: We evaluated all patients who had placement of rigid absorbable reconstruction plates in the anterior skull base in a variety of extrasellar locations and describe results and complications compared with other published techniques. METHODS: A retrospective review was conducted of consecutive patients at a tertiary referral institution who underwent endoscopic extrasellar skull base reconstruction, 2012-2019, using resorbable poly (D,L) lactic acid plates (Resorb-X Sellar Wall Plate; KLS Martin; Jacksonville, FL). Data reviewed included demographic information, indication for surgery, location and size of defect, pathology, peri-operative use of cerebrospinal fluid (CSF) diversion, postoperative complications, post-operative CSF leak, adjuvant therapy, and length of follow-up. RESULTS: Twenty-four subjects and 25 operative procedures met inclusion criteria. Mean age was 53 years (range 11-77). Average BMI was 34 kg/m2. Mean follow-up time was 30 months (range 1-78). Indications for surgery were CSF rhinorrhea (spontaneous, post-traumatic, or iatrogenic) or reconstruction after tumor resection. Four cases were revision procedures. Twenty patients had lumbar drains placed intraoperatively. Only two nasoseptal flaps and two free mucosal grafts were used. None of the patients had a postoperative CSF leak. There was no mortality or morbidity related to the skull base reconstruction or implanted material. CONCLUSION: The Resorb-X resorbable rigid plate provides an effective, customizable, bioabsorbable option that is easily manipulated for skull base reconstruction of defects of a variety of sizes in diverse locations. Reconstruction incorporating this plate provides an effective alternative to other previously described techniques.

Rationale and Design of the PAIRED Trial: Partnered Dance Aerobic Exercise as a Neuroprotective, Motor, and Cognitive Intervention in Parkinson's Disease.

Parkinson's disease (PD), an intractable condition impairing motor and cognitive function, is imperfectly treated by drugs and surgery. Two priority issues for many people with PD are OFF-time and cognitive impairment. Even under best medical management, three-fourths of people with PD experience "OFF-time" related to medication-related motor fluctuations, which severely impacts both quality of life and cognition. Cognitive deficits are found even in newly diagnosed people with PD and are often intractable. Our data suggest that partnered dance aerobic exercise (PDAE) reduces OFF-time on the Movement Disorders Society Unified Parkinson Disease Rating Scale-IV (MDS-UPDRS-IV) and ameliorates other disease features, which motivate the PAIRED trial. PDAE provides AE during an improvisational, cognitively engaging rehabilitative physical activity. Although exercise benefits motor and cognitive symptoms and may be neuroprotective for PD, studies using robust biomarkers of neuroprotection in humans are rare. We propose to perform a randomized, controlled trial in individuals with diagnosed mild-moderate PD to compare the efficacy of PDAE vs. walking aerobic exercise (WALK) for OFF-time, cognition, and neuroprotection. We will assess neuroprotection with neuromelanin-sensitive MRI (NM-MRI) and iron-sensitive (R2*) MRI sequences to quantify neuromelanin loss and iron accumulation in substantia nigra pars compacta (SNc). We will use these biomarkers, neuromelanin loss, and iron accumulation, as tools to chart the course of neurodegeneration in patients with PD who have undergone long-term (16 months) intervention. We will randomly assign 102 individuals with mild-moderate PD to 16 months of PDAE or WALK. The 16-month intervention period will consist of Training (3 months of biweekly sessions) and Maintenance (13 months of weekly sessions) phases. We will assess participants at baseline, 3 months (immediately post-Training), and 16 months (immediately post-Maintenance) for OFF-time and behaviorally and physiologically measured cognition. We will acquire NM-MRI and R2* imaging data at baseline and 16 months to assess neuroprotection. We will (1) examine effects of Training and Maintenance phases of PDAE vs. WALK on OFF-time, (2) compare PDAE vs. WALK at 3 and 16 months on behavioral and functional MRI (fMRI) measures of spatial cognition, and (3) compare PDAE vs. WALK for effects on rates of neurodegeneration.

Genome-wide analysis of canine oral malignant melanoma metastasis-associated gene expression.

Oral malignant melanoma (OMM) is the most common canine melanocytic neoplasm. Overlap between the somatic mutation profiles of canine OMM and human mucosal melanomas suggest a shared UV-independent molecular aetiology. In common with human mucosal melanomas, most canine OMM metastasise. There is no reliable means of predicting canine OMM metastasis, and systemic therapies for metastatic disease are largely palliative. Herein, we employed exon microarrays for comparative expression profiling of FFPE biopsies of 18 primary canine OMM that metastasised and 10 primary OMM that did not metastasise. Genes displaying metastasis-associated expression may be targets for anti-metastasis treatments, and biomarkers of OMM metastasis. Reduced expression of CXCL12 in the metastasising OMMs implies that the CXCR4/CXCL12 axis may be involved in OMM metastasis. Increased expression of APOBEC3A in the metastasising OMMs may indicate APOBEC3A-induced double-strand DNA breaks and pro-metastatic hypermutation. DNA double strand breakage triggers the DNA damage response network and two Fanconi anaemia DNA repair pathway members showed elevated expression in the metastasising OMMs. Cross-validation was employed to test a Linear Discriminant Analysis classifier based upon the RT-qPCR-measured expression levels of CXCL12, APOBEC3A and RPL29. Classification accuracies of 94% (metastasising OMMs) and 86% (non-metastasising OMMs) were estimated.

Genome-wide association study across European and African American ancestries identifies a SNP in DNMT3B contributing to nicotine dependence.

Cigarette smoking is a leading cause of preventable mortality worldwide. Nicotine dependence, which reduces the likelihood of quitting smoking, is a heritable trait with firmly established associations with sequence variants in nicotine acetylcholine receptor genes and at other loci. To search for additional loci, we conducted a genome-wide association study (GWAS) meta-analysis of nicotine dependence, totaling 38,602 smokers (28,677 Europeans/European Americans and 9925 African Americans) across 15 studies. In this largest-ever GWAS meta-analysis for nicotine dependence and the largest-ever cross-ancestry GWAS meta-analysis for any smoking phenotype, we reconfirmed the well-known CHRNA5-CHRNA3-CHRNB4 genes and further yielded a novel association in the DNA methyltransferase gene DNMT3B. The intronic DNMT3B rs910083-C allele (frequency=44-77%) was associated with increased risk of nicotine dependence at P=3.7 × 10-8 (odds ratio (OR)=1.06 and 95% confidence interval (CI)=1.04-1.07 for severe vs mild dependence). The association was independently confirmed in the UK Biobank (N=48,931) using heavy vs never smoking as a proxy phenotype (P=3.6 × 10-4, OR=1.05, and 95% CI=1.02-1.08). Rs910083-C is also associated with increased risk of squamous cell lung carcinoma in the International Lung Cancer Consortium (N=60,586, meta-analysis P=0.0095, OR=1.05, and 95% CI=1.01-1.09). Moreover, rs910083-C was implicated as a cis-methylation quantitative trait locus (QTL) variant associated with higher DNMT3B methylation in fetal brain (N=166, P=2.3 × 10-26) and a cis-expression QTL variant associated with higher DNMT3B expression in adult cerebellum from the Genotype-Tissue Expression project (N=103, P=3.0 × 10-6) and the independent Brain eQTL Almanac (N=134, P=0.028). This novel DNMT3B cis-acting QTL variant highlights the importance of genetically influenced regulation in brain on the risks of nicotine dependence, heavy smoking and consequent lung cancer.

Radiation therapists' and radiation oncology medical physicists' perceptions of work and the working environment in Australia: a qualitative study.

Workforce recruitment and retention are issues in radiation oncology. The working environment is likely to have an impact on retention; however, there is a lack of research in this area. The objectives of this study were to: investigate radiation therapists' (RTs) and radiation oncology medical physicists' (ROMPs) perceptions of work and the working environment; and determine the factors that influence the ability of RTs and ROMPs to undertake their work and how these factors affect recruitment and retention. Semi-structured interviews were conducted and thematic analysis was used. Twenty-eight RTs and 21 ROMPs participated. The overarching themes were delivering care, support in work, working conditions and lifestyle. The overarching themes were mostly consistent across both groups; however, the exemplars reflected the different roles and perspectives of RTs and ROMPs. Participants described the importance they placed on treating patients and improving their lives. Working conditions were sometimes difficult with participants reporting pressure at work, large workloads and longer hours and overtime. Insufficient staff numbers impacted on the effectiveness of staff, the working environment and intentions to stay. Staff satisfaction is likely to be improved if changes are made to the working environment. We make recommendations that may assist departments to support RTs and ROMPs.

TLR9 re-expression in cancer cells extends the S-phase and stabilizes p16(INK4a) protein expression.

Toll-like receptor 9 (TLR9) recognizes bacterial, viral or cell damage-associated DNA, which initiates innate immune responses. We have previously shown that TLR9 expression is downregulated in several viral induced cancers including HPV16-induced cervical neoplasia. Findings supported that downregulation of TLR9 expression is involved in loss of anti-viral innate immunity allowing an efficient viral replication. Here we investigated the role of TLR9 in altering the growth of transformed epithelial cells. Re-introducing TLR9 under the control of an exogenous promoter in cervical or head and neck cancer patient-derived cells reduced cell proliferation, colony formation and prevented independent growth of cells under soft agar. Neither TLR3, 7, nor the TLR adapter protein MyD88 expression had any effect on cell proliferation, indicating that TLR9 has a unique role in controlling cell growth. The reduction of cell growth was not due to apoptosis or necrosis, yet we observed that cells expressing TLR9 were slower in entering the S-phase of the cell cycle. Microarray-based gene expression profiling analysis highlighted a strong interferon (IFN) signature in TLR9-expressing head and neck cancer cells, with an increase in IFN-type I and IL-29 expression (IFN-type III), yet neither IFN-type I nor IL-29 production was responsible for the block in cell growth. We observed that the protein half-life of p16(INK4a) was increased in TLR9-expressing cells. Taken together, these data show for the first time that TLR9 affects the cell cycle by regulating p16(INK4a) post-translational modifications and highlights the role of TLR9 in the events that lead to carcinogenesis.

Discovery of an expanded set of avian leukosis subgroup E proviruses in chickens using Vermillion, a novel sequence capture and analysis pipeline [corrected].

Transposable elements (TEs), such as endogenous retroviruses (ERVs), are common in the genomes of vertebrates. ERVs result from retroviral infections of germ-line cells, and once integrated into host DNA they become part of the host's heritable genetic material. ERVs have been ascribed positive effects on host physiology such as the generation of novel, adaptive genetic variation and resistance to infection, as well as negative effects as agents of tumorigenesis and disease. The avian leukosis virus subgroup E family (ALVE) of endogenous viruses of chickens has been used as a model system for studying the effects of ERVs on host physiology, and approximately 30 distinct ALVE proviruses have been described in the Gallus gallus genome. In this report we describe the development of a software tool, which we call Vermillion, and the use of this tool in combination with targeted next-generation sequencing (NGS) to increase the number of known proviruses belonging to the ALVE family of ERVs in the chicken genome by 4-fold, including expanding the number of known ALVE elements on chromosome 1 (Gga1) from the current 9 to a total of 40. Although we focused on the discovery of ALVE elements in chickens, with appropriate selection of target sequences Vermillion can be used to develop profiles of other families of ERVs and TEs in chickens as well as in species other than the chicken.

Alcohol dehydrogenase and aldehyde dehydrogenase gene polymorphisms, alcohol intake and the risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition study.

BACKGROUND/OBJECTIVES: Heavy alcohol drinking is a risk factor of colorectal cancer (CRC), but little is known on the effect of polymorphisms in the alcohol-metabolizing enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) on the alcohol-related risk of CRC in Caucasian populations. SUBJECTS/METHODS: A nested case-control study (1269 cases matched to 2107 controls by sex, age, study centre and date of blood collection) was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) to evaluate the impact of rs1229984 (ADH1B), rs1573496 (ADH7) and rs441 (ALDH2) polymorphisms on CRC risk. Using the wild-type variant of each polymorphism as reference category, CRC risk estimates were calculated using conditional logistic regression, with adjustment for matching factors. RESULTS: Individuals carrying one copy of the rs1229984(A) (ADH1B) allele (fast metabolizers) showed an average daily alcohol intake of 4.3 g per day lower than subjects with two copies of the rs1229984(G) allele (slow metabolizers) (P(diff)<0.01). None of the polymorphisms was associated with risk of CRC or cancers of the colon or rectum. Heavy alcohol intake was more strongly associated with CRC risk among carriers of the rs1573496(C) allele, with odds ratio equal to 2.13 (95% confidence interval: 1.26-3.59) compared with wild-type subjects with low alcohol consumption (P(interaction)=0.07). CONCLUSIONS: The rs1229984(A) (ADH1B) allele was associated with a reduction in alcohol consumption. The rs1229984 (ADH1B), rs1573496 (ADH7) and rs441 (ALDH2) polymorphisms were not associated with CRC risk overall in Western-European populations. However, the relationship between alcohol and CRC risk might be modulated by the rs1573496 (ADH7) polymorphism.

Diet induced epigenetic changes and their implications for health.

Dietary exposures can have consequences for health years or decades later and this raises questions about the mechanisms through which such exposures are 'remembered' and how they result in altered disease risk. There is growing evidence that epigenetic mechanisms may mediate the effects of nutrition and may be causal for the development of common complex (or chronic) diseases. Epigenetics encompasses changes to marks on the genome (and associated cellular machinery) that are copied from one cell generation to the next, which may alter gene expression, but which do not involve changes in the primary DNA sequence. These include three distinct, but closely inter-acting, mechanisms including DNA methylation, histone modifications and non-coding microRNAs (miRNA) which, together, are responsible for regulating gene expression not only during cellular differentiation in embryonic and foetal development but also throughout the life-course. This review summarizes the growing evidence that numerous dietary factors, including micronutrients and non-nutrient dietary components such as genistein and polyphenols, can modify epigenetic marks. In some cases, for example, effects of altered dietary supply of methyl donors on DNA methylation, there are plausible explanations for the observed epigenetic changes, but to a large extent, the mechanisms responsible for diet-epigenome-health relationships remain to be discovered. In addition, relatively little is known about which epigenomic marks are most labile in response to dietary exposures. Given the plasticity of epigenetic marks and their responsiveness to dietary factors, there is potential for the development of epigenetic marks as biomarkers of health for use in intervention studies.

Genetic variation at the tumour virus B locus in commercial and laboratory chicken populations assessed by a medium-throughput or a high-throughput assay.

The tumour virus B (TVB) locus encodes cellular receptors mediating infection by three subgroups of avian leukosis virus (B, D, and E). Three major alleles, TVB*S1, TVB*S3, and TVB*R, have been described. TVB*S1 encodes a cellular receptor mediating infection of subgroups B, D, and E. TVB*S3 encodes the receptor for two subgroups, B and D, and TVB*R encodes a dysfunctional receptor that does not permit infection by any of the subgroups, B, D, or E. Genetic diversity at the TVB locus of chickens was investigated in both layer and broiler commercial pure lines and laboratory lines. Genotyping assays were developed for both medium-throughput and high-throughput analysis. Of the 36 broiler lines sampled, 14 were fixed for the susceptible allele TVB*S1. Across all broiler lines, 83% of chickens were typed as TVB*S1/*S1, 3% as TVB*R/*R, and 14% as TVB*S1/*R. In the egg-layer lines, five of the 16 tested were fixed for TVB*S1/*S1. About 44% of egg-layers were typed as TVB*S1/*S1, 15% as TVB*R/*R, with the rest segregating for two or three of the alleles. In the laboratory chickens, 60% were fixed for TVB*S1/*S1, 6% for TVB*S3/*S3, 14% for TVB*R/*R, and the rest were heterozygotes (TVB*S1/*S3 or TVB*S1/*R). All commercial pure lines examined in this study carry the TVB*S1 allele that sustains the susceptibility to avian leukosis viruses B, D, and E. More importantly, the TVB*R allele was identified in multiple populations, thus upholding the opportunities for genetic improvement through selection.

Polymorphisms of genes coding for insulin-like growth factor 1 and its major binding proteins, circulating levels of IGF-I and IGFBP-3 and breast cancer risk: results from the EPIC study.

Insulin-like growth factor I (IGF-I) stimulates cell proliferation and can enhance the development of tumours in different organs. Epidemiological studies have shown that an elevated level of circulating IGF-I is associated with increased risk of breast cancer, as well as of other cancers. Most of circulating IGF-I is bound to an acid-labile subunit and to one of six insulin-like growth factor binding proteins (IGFBPs), among which the most important are IGFBP-3 and IGFBP-1. Polymorphisms of the IGF1 gene and of genes encoding for the major IGF-I carriers may predict circulating levels of IGF-I and have an impact on cancer risk. We tested this hypothesis with a case-control study of 807 breast cancer patients and 1588 matched control subjects, nested within the European Prospective Investigation into Cancer and Nutrition. We genotyped 23 common single nucleotide polymorphisms in IGF1, IGFBP1, IGFBP3 and IGFALS, and measured serum levels of IGF-I and IGFBP-3 in samples of cases and controls. We found a weak but significant association of polymorphisms at the 5' end of the IGF1 gene with breast cancer risk, particularly among women younger than 55 years, and a strong association of polymorphisms located in the 5' end of IGFBP3 with circulating levels of IGFBP-3, which confirms previous findings. Common genetic variation in these candidate genes does not play a major role in altering breast cancer risk in Caucasians.

Neuronal nitric oxide synthase and nerve growth factor expression in the enteric nervous system.

The role of nitric oxide (NO) in various systems of the body has gained prominence since the last decade. The dual role of NO either as a toxic or protective molecule depends on the concentrations of NO being produced, the isoform of NO synthase involved and the type of cell in which NO produced. The protective roles of NO appear to be mediated via cross talk between neurotrophic pathways. In view of this, in this paper, the role of NO in the enteric system is discussed with respect to neuronal nitric oxide synthase expression in neurons associated with the gut and the nerve growth factor and its receptor, tyrosine kinase A expression in the lamina epithelialis.

Folate and DNA methylation during in utero development and aging.

DNA methylation is one of several epigenetic mechanisms that play a regulatory role in genome programming and imprinting during embryogenesis. Aberrant DNA methylation has been implicated in the pathogenesis of a number of diseases associated with aging, including cancer and cardiovascular and neurological diseases. Evidence is accumulating that dietary factors in utero modulate disease risk in later life. Although folic acid is a key component of DNA methylation, the impact of folic acid availability in utero on DNA methylation patterns and disease risk in adulthood is at present poorly characterized. This review describes the relationship between folic acid and DNA methylation, and the association between DNA methylation during in utero development and aging.

Evidence for interaction between the TCO and NMTC1 loci in familial non-medullary thyroid cancer.

BACKGROUND: Familial non-medullary thyroid cancer (fNMTC) is a complex genetic disorder that is more aggressive than its sporadic counterpart. Thus far, three genetic loci have been implicated in susceptibility to fNMTC by linkage analysis. METHODS: We used linkage analysis to test the significance of two of the known susceptibility loci for fNMTC, TCO on 19p13 and NMTC1 on 2q21 in 10 fNMTC families, nine of which present with cell oxyphilia, a rare histological phenotype associated with TCO. Furthermore, we used two-locus linkage analysis to examine the possibility that the TCO and NMTC1 loci interact to increase the risk of NMTC. RESULTS: The 10 families provided evidence for linkage at both TCO and NMTC, with LOD scores of 1.56 and 2.85, respectively. Two-locus linkage analysis, using a multiplicative risk model for the development of NMTC, achieved a maximum LOD of 3.92, with an LOD of 4.51 when assuming 70% of families were linked, indicating that the segregation in these families is consistent with an interaction model. Most of this evidence came from a large Tyrolean family that singularly achieved a two-locus LOD of 3.21. CONCLUSIONS: These results provide further evidence that susceptibility genes for fNMTC exist at 19p13 and 2q21, and furthermore, raise the possibility that in a subset of fNMTC pedigrees, these loci interact resulting in significantly increased risk of NMTC for patients that carry both susceptibility loci.

Evaluation of the epidermal growth factor receptor (EGFR) in colorectal tumours and lymph node metastases.

Overexpression of the epidermal growth factor receptor (EGFR) often correlates with an aggressive tumour phenotype and poor prognosis. To examine the relevance of EGFR in colorectal cancer, we determined the expression of EGFR protein in 249 colorectal adenocarcinomas and 42 lymph node metastases using immunohistochemistry. Moreover, we investigated a (CA)(n) dinucleotide repeat polymorphism of the EGFR gene in a subset of 114 tumours. High levels of EGFR protein were observed in 123/249 (49.4%) samples. EGFR expression in colorectal carcinomas correlated with differentiation grade (P=0.014). However, there were no associations with Dukes' stage, site, patient age or gender. EGFR protein expression did not influence survival in this colorectal cancer patient cohort (P>or=0.05). Expression was not identical in paired colorectal tumours and lymph node metastases, with only 17/42 (40.5%) samples showing equivalent EGFR levels (P>0.05). The distribution of the (CA)(n) dinucleotide repeat alleles in colorectal adenocarcinomas was not associated with EGFR protein expression (P>0.05). These results indicate that while EGFR overexpression is a common event in colorectal carcinogenesis, it does not influence patient prognosis.

Matrix metalloproteinase 13 activity is associated with poor prognosis in colorectal cancer.

AIMS: The matrix metalloproteinases (MMPs) are a family of proteolytic enzymes collectively capable of degrading all extracellular matrix components, in particular fibrillar collagen. The importance of this group of proteins in the processes of tumour invasion and metastasis is now widely acknowledged. MMP-13 (collagenase 3) has a central role in the MMP activation cascade. The purpose of this study was to investigate the presence and activity of MMP-13 in colorectal cancer and relate these to clinicopathological features. METHODS: Immunohistochemistry for MMP-13 was performed on formalin fixed, paraffin wax embedded sections of a large series of colorectal cancers (n = 249), all of which had uniform clinical and pathological information available. Immunoreactivity to MMP-13 was detected with a monoclonal antibody to MMP-13 using a Dako TechMate 500 automated immunostaining system. The presence and cellular localisation of MMP-13 was assessed using a semiquantitative scoring system. Gelatin zymography was used to detect and measure MMP-13 activity. The zymography was performed on a subset of the cases studied by immunohistochemistry using two groups of 10 paired Dukes's C tumours and normal samples, selected by either having "good" or "poor" survival. RESULTS: Immunoreactivity to MMP-13 was identified in 91% of cases and immunoreactivity was localised to the cytoplasm of tumour cells. A high MMP-13 staining score showed a trend towards poorer survival. Tumours had significantly greater MMP-13 activity compared with normal colonic mucosa (p < 0.001). Furthermore, the tumour to normal tissue ratio was significantly higher in the poor survival group (p = 0.02). CONCLUSIONS: These results show that MMP-13 is frequently present and active in colorectal cancer and suggest that the activity of MMP-13 is associated with poorer survival in colorectal cancer.