Health-related Quality of Life of Patients With Non-Intra-abdominal Desmoid-Type Fibromatosis During Active Surveillance: Results of a Prospective Observational Study.

OBJECTIVE: To examine the impact of an active surveillance (AS) approach on the health-related quality of life (HRQoL) of patients with desmoid-type fibromatosis (DTF). BACKGROUND DATA: AS is recommended as initial approach in DTF patients. AS might however negatively affect HRQoL due to physical symptoms or stress and anxiety. METHODS: In a prospective observational study, the GRAFITI trial (NTR4714), DTF patients were followed during an initial AS approach for 3 years. HRQoL was assessed by the EORTC QLQ-C30 at baseline, 6, 12 and 24-month follow-up. Patients who completed questionnaires at≥1-time point were included in this analysis of the secondary endpoint. A multivariable linear mixed-effects model with random intercept was conducted to assess trends of HRQoL scores over time and to explore the effect of treatment strategy on HRQoL. RESULTS: All 105 patients enrolled in the GRAFITI trial were eligible for the HRQoL analyses. During 24-month follow-up, 75 patients (71%) continued AS and 30 patients (29%) started an active treatment (AT). DTF patients who continued AS demonstrated relatively stable HRQoL scores during follow-up. HRQoL scores of patients who started AT worsened compared to patients who continued AS, although no significant changes in HRQoL score over time were found in the mixed-model analyses. Overall, DTF patients who started AT scored significantly worse on pain (ß=10.08, P =0.039) compared to patients who continued AS. CONCLUSIONS: An initial AS approach did not impair HRQoL of DTF patients who continued AS over time, therefore providing further support for AS as the frontline approach in DTF patients. Longitudinal assessment of HRQoL should be part of clinical follow-up to identify patients who may need a change in treatment strategy.

A Nationwide Prospective Clinical Trial on Active Surveillance in Patients With Non-intraabdominal Desmoid-type Fibromatosis: The GRAFITI Trial.

OBJECTIVE: To assess tumor behavior and the efficacy of active surveillance (AS) in patients with desmoid-type fibromatosis (DTF). SUMMARY OF BACKGROUND DATA: AS is recommended as initial management for DTF patients. Prospective data regarding the results of AS are lacking. METHODS: In this multicenter prospective cohort study (NTR4714), adult patients with non-intraabdominal DTF were followed during an initial AS approach for 3 years. Tumor behavior was evaluated according to Response Evaluation Criteria in Solid Tumors. Cumulative incidence of the start of an active treatment and progression-free survival (PFS) were calculated using the Kaplan-Meier method. Factors predictive for start of active treatment were assessed by Cox regression analyses. RESULTS: A total of 105 patients started with AS. Median tumor size at baseline was 4.1cm (interquartile range 3.0-6.6). Fifty-seven patients had a T41A CTNNB1 mutation; 14 patients a S45F CTNNB1 mutation. At 3 years, cumulative incidence of the start of active treatment was 30% (95% confidence interval [CI] 21-39) and PFS was 58% (95% CI 49-69). Median time to start active treatment and PFS were not reached at a median follow-up of 33.7 months. During AS, 32% of patients had stable disease, 28% regressed, and 40% demonstrated initial progression. Larger tumor size (≥5 cm; hazard ratio = 2.38 [95% CI 1.15-4.90]) and S45F mutation (hazard ratio = 6.24 [95% CI 1.92-20.30]) were associated with the start of active treatment. CONCLUSIONS: The majority DTF patients undergoing AS do not need an active treatment and experience stable or regressive disease, even after initial progression. Knowledge about the natural behavior of DTF will help to tailor the follow-up schedule to the individual patient.

Differential Diagnosis and Molecular Stratification of Gastrointestinal Stromal Tumors on CT Images Using a Radiomics Approach.

Treatment planning of gastrointestinal stromal tumors (GISTs) includes distinguishing GISTs from other intra-abdominal tumors and GISTs' molecular analysis. The aim of this study was to evaluate radiomics for distinguishing GISTs from other intra-abdominal tumors, and in GISTs, predict the c-KIT, PDGFRA, BRAF mutational status, and mitotic index (MI). Patients diagnosed at the Erasmus MC between 2004 and 2017, with GIST or non-GIST intra-abdominal tumors and a contrast-enhanced venous-phase CT, were retrospectively included. Tumors were segmented, from which 564 image features were extracted. Prediction models were constructed using a combination of machine learning approaches. The evaluation was performed in a 100 × random-split cross-validation. Model performance was compared to that of three radiologists. One hundred twenty-five GISTs and 122 non-GISTs were included. The GIST vs. non-GIST radiomics model had a mean area under the curve (AUC) of 0.77. Three radiologists had an AUC of 0.69, 0.76, and 0.84, respectively. The radiomics model had an AUC of 0.52 for c-KIT, 0.56 for c-KIT exon 11, and 0.52 for the MI. The numbers of PDGFRA, BRAF, and other c-KIT mutations were too low for analysis. Our radiomics model was able to distinguish GISTs from non-GISTs with a performance similar to three radiologists, but less observer dependent. Therefore, it may aid in the early diagnosis of GIST, facilitating rapid referral to specialized treatment centers. As the model was not able to predict any genetic or molecular features, it cannot aid in treatment planning yet.

The Prognostic Role of ß-Catenin Mutations in Desmoid-type Fibromatosis Undergoing Resection Only: A Meta-analysis of Individual Patient Data.

OBJECTIVE: This meta-analysis (PROSPERO CRD42018100653) uses individual patient data (IPD) to assess the association between recurrence and CTNNB1 mutation status in surgically treated adult desmoid-type fibromatosis (DTF) patients. SUMMARY OF BACKGROUND DATA: The majority of sporadic DTF tumors harbor a CTNNB1 (ß-catenin) mutation: T41A, S45F, and S45P or are wild-type (WT). Results are conflicting regarding the recurrence risk after surgery for these mutation types. METHODS: A systematic literature search was performed on June 6th, 2018. IPD from eligible studies was used to analyze differences in recurrence according to CTNNB1 mutation status using Cox proportional hazards analysis. Predictive factors included: sex, age, mutation type, tumor site, tumor size, resection margin status, and cohort. The PRISMA-IPD guideline was used. RESULTS: Seven studies, describing retrospective cohorts were included and the IPD of 329 patients were used of whom 154 (46.8%) had a T41A mutation, 66 (20.1%) a S45F mutation, and 24 (7.3%) a S45P mutation, whereas 85 (25.8%) patients had a WT CTNNB1. Eighty-three patients (25.2%) experienced recurrence. Multivariable analysis, adjusting for sex, age, and tumor site yielded a P-value of 0.011 for CTNNB1 mutation. Additional adjustment for tumor size yielded a P-value of 0.082 with hazard ratio's of 0.83 [95% confidence interval (CI) 0.48-1.42), 0.37 (95% CI 0.12-1.14), and 0.44 (95% CI 0.21-0.92) for T41A, S45P and WT DTF tumors compared to S45F DTF tumors. The effect modification between tumor size and mutation type suggests that tumor size is an important mediator for recurrence. CONCLUSIONS: Primary sporadic DTFs harboring a CTNNB1 S45F mutation have a higher risk of recurrence after surgery compared to T41A, S45P, and WT DTF, but this association seems to be mediated by tumor size.

Identification and assessment of health-related quality of life issues in patients with sporadic desmoid-type fibromatosis: a literature review and focus group study.

PURPOSE: Sporadic desmoid-type fibromatosis (DTF) is a rare, chronic, non-metastasising, disease of the soft tissues. It is characterised by local invasive and unpredictable growth behaviour and a high propensity of local recurrence after surgery thereby often having a great impact on health-related quality of life (HRQL). This study aims to review currently used HRQL measures and to asses HRQL issues among DTF patients. METHODS: A mixed methods methodology was used consisting of (1) a systematic literature review, according to the PRISMA guidelines (2009), using search terms related to sporadic DTF and HRQL in commonly used databases (e.g. Embase, Medline Ovid, Web of science, Cochrane Central, Psyc Info, and Google scholar), to provide an overview of measures previously used to evaluate HRQL among DTF patients; (2) focus groups to gain insight into HRQL issues experienced by DTF patients. RESULTS: The search strategy identified thirteen articles reporting HRQL measures using a wide variety of cancer-specific HRQL tools, functional scores, symptom scales (e.g. NRS), and single-item outcomes (e.g. pain and functional impairment). No DTF-specific HRQL tool was found. Qualitative analysis of three focus groups (6 males, 9 females) showed that participants emphasised the negative impact of DTF and/or its treatment on several HRQL domains. Six themes were identified: (1) diagnosis, (2) treatment, (3) follow-up and recurrence, (4) physical domain, (5) psychological and emotional domain, and (6) social domain. CONCLUSION: A DTF-specific HRQL tool and consensus regarding the preferred measurement tool among DTF patients is lacking. Our study indicates that HRQL of DTF patients was negatively affected in several domains. A DTF-specific HRQL measure could improve our understanding of short- and long-term effects and, ideally, can be used in both clinic and for research purposes.

Physical symptom burden in patients with desmoid-type fibromatosis and its impact on health-related quality of life and healthcare use.

BACKGROUND: Desmoid-type fibromatosis (DTF) has a highly variable clinical course with varying intensity of symptoms. The objectives of this study were to identify subgroups of DTF patients based on physical symptom burden and to compare symptom burden subgroups on health-related quality of life (HRQoL) and healthcare use (univariate and multivariate). METHODS: Desmoid-type fibromatosis patients from the United Kingdom and the Netherlands received cross-sectional questionnaires on HRQoL (EORTC QLQ-C30), DTF-specific HRQoL (DTF-QoL) and healthcare utilisation. Latent class cluster analysis was performed to identify subgroups based on patients' symptom burden using EORTC QLQ-C30 and DTF-QoL physical symptom items. Multivariate linear and logistic regression analyses were conducted to examine associations of symptom burden with HRQoL and healthcare utilisation, respectively. RESULTS: Among 235 DTF patients, four symptom burden clusters were identified, with low symptom burden (24%), intermediate symptom burden-low pain (20%), intermediate symptom burden-high pain (25%) and high symptom burden (31%). DTF patients with high symptom burden had clinically relevant lower HRQoL scores compared to patients with low and intermediate symptom burden (p < 0.001) and reported more general and DTF-related visits to their general practitioner compared to the low symptom burden cluster (p < 0.01). In the multivariate analyses, symptom burden was independently associated with both HRQoL and healthcare utilisation. CONCLUSIONS: This study identified four distinct subgroups of DTF patients based on their level of symptom burden, with a considerable number of patients being highly symptomatic. Knowledge of the level of symptom burden DTF patients experience can help to identify patients at risk of poorer outcomes and tailor supportive care to the individual needs of DTF patients.

In desmoid-type fibromatosis cells sorafenib induces ferroptosis and apoptosis, which are enhanced by autophagy inhibition.

INTRODUCTION: Desmoid-type fibromatosis (DTF) is a rare, soft tissue tumour. Sorafenib, a multikinase inhibitor, has demonstrated antitumour efficacy in DTF patients. Little is known about the underlying molecular mechanisms, which are crucial to know to further optimize systemic treatments. Here we investigated the molecular effects of sorafenib exposure on DTF and stromal cells, with an emphasis on cell death mechanisms. MATERIAL AND METHODS: DTF primary cell cultures, with known CTNNB1 status, and primary stromal cell cultures, derived from DTF tissue, were exposed to clinically relevant concentrations of sorafenib in the presence or absence of inhibitors of ferroptosis, apoptosis and autophagy. Cell viability was determined after 24 and 48 h using MTT assays. Annexin V/PI staining, lipid peroxidation analysis and immunoblotting were performed to assess apoptosis, ferroptosis and autophagy. RESULTS: Exposure to sorafenib caused a significant, concentration- and time-dependent decrease in cell viability in all primary DTF and stromal cell cultures. Inhibitors of ferroptosis and apoptosis protected against sorafenib-mediated cytotoxicity implicating that both cell death mechanisms are activated. Annexin V/PI stainings and lipid peroxidation analyses confirmed induction of apoptosis and ferroptosis, respectively. Autophagy inhibition enhanced the cytotoxic effect of sorafenib and led to a stronger induction of apoptosis and ferroptosis. CONCLUSION: This study identified ferroptosis and apoptosis as mechanisms for the sorafenib induced cell death in DTF cells as well as stromal cells. Furthermore, autophagy inhibition enhanced the cytotoxic effects of sorafenib. Knowledge of the mechanisms by which sorafenib affects DTF at a cellular level may help to optimize its clinical efficacy and mitigate toxic effects.

Unraveling Desmoid-Type Fibromatosis-Specific Health-Related Quality of Life: Who Is at Risk for Poor Outcomes.

Desmoid-type fibromatosis (DTF) is a rare, soft-tissue tumour. These tumours do not metastasize, but their local aggressive tumour growth and unpredictable behaviour can have a significant impact on health-related quality of life (HRQoL). Little is known about which DTF patients are particularly affected by an impaired HRQoL. The objectives of this study were to assess HRQoL among different groups of DTF patients and to investigate which socio-demographic and clinical characteristics were associated with DTF-specific HRQoL. A cross-sectional study was conducted among DTF patients from the United Kingdom and the Netherlands. HRQoL was assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30), accompanied by the DTF-QoL to assess DTF-specific HRQoL. The scores were compared amongst subgroups, based on the socio-demographic and clinical characteristics of DTF patients. Multiple linear regression analyses with a backward elimination were conducted to identify the factors associated with DTF-specific HRQoL. A total of 235 DTF patients completed the questionnaires. Female patients, patients with more than two comorbidities, or patients who received treatment other than only active surveillance (AS) or surgery scored significantly worse on the subscales of both the EORTC QLQ-C30 and DTF-QoL. Patients that were ≥ 40 years scored significantly worse on the physical functioning scale of the EORTC QLQ-C30, while younger patients (18-39 years) scored significantly worse on several DTF-QoL subscales. Differences in the DTF-QoL subscales were found for tumour location, time since diagnosis and the presence of recurrent disease. Furthermore, treatments other than AS or surgery only, female sex, younger age and the presence of comorbidities were most frequently associated with worse scores on the DTF-QoL subscales. This study showed that (DTF-specific) HRQoL differs between groups of DTF patients. Awareness of these HRQoL differences could help to provide better, personalised care that is tailored to the needs of a specific subgroup.

Development of a Disease-Specific Health-Related Quality of Life Questionnaire (DTF-QoL) for Patients with Desmoid-Type Fibromatosis.

Sporadic desmoid-type fibromatosis (DTF) is a rare, non-metastasising soft-tissue tumour. Patients can experience a variety of disease-specific issues related to the unpredictable clinical course and aggressiveness of DTF, which negatively impacts health-related quality of life (HRQoL). These DTF-specific issues are not captured by generic HRQoL tools. A 102-item provisional DTF-specific HRQoL tool, the DTF-QoL, was previously developed. The aim of this study was to pre-test the psychometric properties of the DTF-QoL by administering it together with the EORTC Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) to 236 DTF patients from the United Kingdom and the Netherlands. Construct validity and reliability were determined based on factor analysis, multi-trait scaling analysis, Cronbach's alpha, and correlations with the EORTC QLQ-C30 scales. Ninety-six items were selected, conceptualised into three symptom scales, eleven disease-impact scales and six single items, together forming the final DTF-QoL. Scaling assumptions were fully or moderately met for ten out of fourteen scales. Cronbach's alpha ranged from 0.551-0.908. Most scales of the DTF-QoL were weakly or moderately correlated with the EORTC QLQ-C30. The DTF-QoL is a promising tool capturing the whole spectrum of DTF-specific issues. Implementation of the DTF-QoL in research and clinical practice will help to personalise HRQoL measurement and clinical care for DTF patients.

The Evaluation of Health-Related Quality of Life Issues Experienced by Patients with Desmoid-Type Fibromatosis (The QUALIFIED Study)-A Protocol for an International Cohort Study.

Sporadic desmoid-type fibromatosis (DTF) is a rare soft tissue tumour with an unpredictable clinical course. These tumours are incapable of metastasising, but their local aggressive tumour growth and tendency to recur locally can result in a substantial symptom burden. Measuring the impact of DTF on health-related quality of life (HRQoL) can be challenging due to the variable clinical presentation of the disease. Therefore, a HRQoL instrument assessing DTF-specific issues is needed. The QUALIFIED study aims to (1) pre-test a previously developed DTF-specific HRQoL tool (the DTF-QoL); (2) evaluate prevalence of HRQoL issues in adult DTF patients; and (3) identify subgroups at risk of impaired HRQoL. This study (NCT04289077) is an international, multicentre, cross-sectional, observational cohort study. Patients ≥ 18 years with sporadic DTF from the Netherlands and the United Kingdom will be invited to complete a set of questionnaires specifically composed for this patient group. Questionnaires will be completed using PROFILES (Patient Reported Outcomes Following Initial treatment and Long-term Evaluation of Survivorship). Analyses will include testing the psychometric properties of the DTF-QoL and evaluating the prevalence of HRQoL issues using the DTF-QoL, EORTC QOL-C30 and EQ-5D-5L, among other questionnaires. This study will provide insight into HRQoL issues experienced by patients with DTF. Awareness of these issues and the implementation of the DTF-QoL in research and clinical practice can help to improve overall HRQoL and to provide personalised care.

Active surveillance in desmoid-type fibromatosis: A systematic literature review.

BACKGROUND: This study evaluates the results of the active surveillance (AS) approach in adult patients with desmoid-type fibromatosis (DTF) because AS is advocated as a front-line approach for DTF in the European consensus guidelines. METHODS: A systematic literature search was conducted (December 19th, 2019, updated on April 14th, 2020). Studies describing the outcomes of the AS approach were included. The PRISMA guidelines were used. RESULTS: Twenty-five articles were included for data retrieval. Forty-two percent of reported patients (1480 of 3527 patients) received AS, the majority were women and the majority had a primary tumour. The median age at diagnosis ranged from 28 to 59 years. Common tumour sites were the extremities/girdles (n = 273), the abdominal wall (n = 253) and the trunk (n = 153). The median reported percentage of progressive disease, stable disease and partial response was 20% (interquartile range [IQR]: 13-35%), 59% (IQR: 37-69%) and 19% (IQR 3-23%), respectively. In 640 patients, the outcome was not specified. The median reported percentage of shifting to an active form of treatment was 29%, most commonly to systemic treatment (n = 195) and surgery (n = 107). The reported median follow-up time ranged between 8 and 73 months. The reported median time to progression and/or initiation of the subgroup shifting from AS to 'active' therapy ranged from 6.3 months to 19.7 months. CONCLUSION: The majority of patients undergoing AS have either stable disease or a partial response, and about one-third of patients shift to an active form of treatment. Selecting patients who will benefit from active surveillance upfront should be the priority of future studies.

Assessing the Desmoid-Type Fibromatosis Patients' Voice: Comparison of Health-Related Quality of Life Experiences from Patients of Two Countries.

PURPOSE: Desmoid-type fibromatosis (DTF) is a rare, nonmetastasising soft tissue tumour. Symptoms, unpredictable growth, lack of definitive treatments, and the chronic character of the disease can significantly impact health-related quality of life (HRQoL). We aimed at identifying the most important HRQoL issues according to DTF patients in two countries, in order to devise a specific HRQoL questionnaire for this patient group. METHODS: DTF patients and healthcare providers (HCPs) from the Netherlands and the United Kingdom individually ranked 124 issues regarding diagnosis, treatment, follow-up, recurrence, living with DTF, healthcare, and supportive care experiences, according to their relevance. Descriptive statistics were used to calculate priority scores. RESULTS: The most highly ranked issues by patients (n = 29) were issues concerning "tumour growth," "feeling that there is something in the body that does not belong there," and "fear of tumour growth into adjacent tissues or organs" with mean (M) scores of 3.0, 2.9, and 2.8, respectively (Likert scale 1-4). British patients scored higher on most issues compared to Dutch patients (M 2.2 vs. M 1.5). HCPs (n = 31) gave higher scores on most issues compared to patients (M 2.3 vs. M 1.8). CONCLUSION: This study identified the most relevant issues for DTF patients, which should be included in a DTF-specific HRQoL questionnaire. Additionally, we identified differences in priority scores between British and Dutch participating patients. Field testing in a large, international cohort is needed to confirm these findings and to devise a comprehensive and specific HRQoL questionnaire for DTF patients.

Differentially Methylated Regions in Desmoid-Type Fibromatosis: A Comparison Between CTNNB1 S45F and T41A Tumors.

INTRODUCTION: The majority of desmoid-type fibromatosis (DTF) tumors harbor a ß-catenin mutation, affecting specific codons in CTNNB1 exon 3. S45F tumors are reported to have a higher chance of recurrence after surgery and more resistance to systemic treatments compared to wild-type (WT) and T41A tumors. The aim of this pilot study was to examine the genome-wide DNA methylation profiles of S45F and T41A mutated DTF, to explain the observed differences in clinical behavior between these DTF subtypes. MATERIAL AND METHODS: Genome-wide analysis of DNA methylation was performed using MeD-seq on formalin-fixed, paraffin-embedded primary DTF samples harboring a S45F (n = 14) or a T41A (n = 15) mutation. Differentially methylated regions (DMRs) between S45F and T41A DTF were identified and used for a supervised hierarchical cluster analysis. DMRs with a fold-change ≥1.5 were considered to be differentially methylated and differences between S45F and T41A tumors were quantitatively assessed. The effect of DMRs on the expression of associated genes was assessed using an independent mRNA expression dataset. Protein-protein interactions between WT ß-catenin and mutant variants and DNA methyltransferase 1 (DNMT1) were examined by immunoprecipitation experiments. RESULTS: MeD-seq analyses indicated 354 regions that displayed differential methylation. Cluster analysis yielded no distinct clusters based on mutation, sex, tumor site or tumor size. A supervised clustering based on DMRs between small (≤34 mm) and large (>87 mm) DTF distinguished the two groups. Only ten DMRs displayed a fold change of ≥1.5 and six of them were found associated with the following genes: NLRP4, FOXK2, PERM1, CCDC6, NOC4L, and DUX4L6. The effects of DMRs on gene expression yielded a significant difference (p < 0.05) in the expression between S45F and T41A for CCDC6 and FOXK2 but not for all Affymetrix probe-sets used to detect these genes. Immunoprecipitations did not reveal an association of WT ß-catenin or mutant variants with DNMT1. CONCLUSION: This study demonstrated that S45F and T41A DTF tumors did not exhibit gross differences in DNA methylation patterns. This implies that distinct DNA methylation profiles are not the sole determinant for the divergent clinical behavior of these different DTF mutant subtypes.

Differential diagnosis and mutation stratification of desmoid-type fibromatosis on MRI using radiomics.

PURPOSE: Diagnosing desmoid-type fibromatosis (DTF) requires an invasive tissue biopsy with ß-catenin staining and CTNNB1 mutational analysis, and is challenging due to its rarity. The aim of this study was to evaluate radiomics for distinguishing DTF from soft tissue sarcomas (STS), and in DTF, for predicting the CTNNB1 mutation types. METHODS: Patients with histologically confirmed extremity STS (non-DTF) or DTF and at least a pretreatment T1-weighted (T1w) MRI scan were retrospectively included. Tumors were semi-automatically annotated on the T1w scans, from which 411 features were extracted. Prediction models were created using a combination of various machine learning approaches. Evaluation was performed through a 100x random-split cross-validation. The model for DTF vs. non-DTF was compared to classification by two radiologists on a location matched subset. RESULTS: The data included 203 patients (72 DTF, 131 STS). The T1w radiomics model showed a mean AUC of 0.79 on the full dataset. Addition of T2w or T1w post-contrast scans did not improve the performance. On the location matched cohort, the T1w model had a mean AUC of 0.88 while the radiologists had an AUC of 0.80 and 0.88, respectively. For the prediction of the CTNNB1 mutation types (S45 F, T41A and wild-type), the T1w model showed an AUC of 0.61, 0.56, and 0.74. CONCLUSIONS: Our radiomics model was able to distinguish DTF from STS with high accuracy similar to two radiologists, but was not able to predict the CTNNB1 mutation status.

Activated Signaling Pathways and Targeted Therapies in Desmoid-Type Fibromatosis: A Literature Review.

Desmoid-type fibromatosis (DTF) is a rare, soft tissue tumor of mesenchymal origin which is characterized by local infiltrative growth behavior. Besides "wait and see," surgery and radiotherapy, several systemic treatments are available for symptomatic patients. Recently, targeted therapies are being explored in DTF. Unfortunately, effective treatment is still hampered by the limited knowledge of the molecular mechanisms that prompt DTF tumorigenesis. Many studies focus on Wnt/ß-catenin signaling, since the vast majority of DTF tumors harbor a mutation in the CTNNB1 gene or the APC gene. The established role of the Wnt/ß-catenin pathway in DTF forms an attractive therapeutic target, however, drugs targeting this pathway are still in an experimental stage and not yet available in the clinic. Only few studies address other signaling pathways which can drive uncontrolled growth in DTF such as: JAK/STAT, Notch, PI3 kinase/AKT, mTOR, Hedgehog, and the estrogen growth regulatory pathways. Evidence for involvement of these pathways in DTF tumorigenesis is limited and predominantly based on the expression levels of key pathway genes, or on observed clinical responses after targeted treatment. No clear driver role for these pathways in DTF has been identified, and a rationale for clinical studies is often lacking. In this review, we highlight common signaling pathways active in DTF and provide an up-to-date overview of their therapeutic potential.

Wnt targets genes are not differentially expressed in desmoid tumors bearing different activating ß-catenin mutations.

INTRODUCTION: Sporadic desmoid-type fibromatosis (DTF) is a rare soft tissue tumor of mesenchymal origin. It is characterized by local invasive growth and unpredictable growth behavior. Three distinct mutations involving the CTNNB1 (ß-catenin) gene have been identified in the vast majority of DTF tumors, which cause activation of the Wnt signaling pathway and impact prognosis. This study examines whether the different CTNNB1 mutants (T41A, S45F) occurring in DTF tumors differentially affect Wnt signaling activity, which might explain the different disease course between DTF patients harboring different CTNNB1 mutations. MATERIALS AND METHODS: Real-time polymerase chain reaction (RT-PCR) on 61 formalin fixed paraffin embedded DTF samples with known CTNNB1 status was used to measure the relative mRNA expression level of Wnt target genes AXIN2, DKK1 and CCND1. Additionally, publicly available mRNA expression data retrieved from the Gene Expression Omnibus of 128 DTF samples were used for an unsupervised cluster analyses based on the expression of a selection of Wnt targets. RESULTS: No statistically significant difference in relative expression levels of Wnt target genes AXIN2, DKK1 and CCND1 was identified between either CTNNB1 wild-type, S45F or T41A mutated DTF samples. Moreover, the hierarchical cluster analyses using selected Wnt targets did not discriminate between different CTNNB1 mutation types. CONCLUSIONS: No differences in the expression levels of Wnt target genes were observed between the different CTNNB1 mutation types in DTF tumors. Further studies are needed to decipher the mechanism accounting for the diverse disease courses between DTF patients with different CTNNB1 variants.

[A woman with increasing pain after cholecystectomy]. / Een vrouw met toenemende buikpijn na cholecystectomie.

A 25-year-old female presented with abdominal pain and collapse 3 days after a laparoscopic cholecystectomy. The MRCP images suggested a leakage from the stump of the cystic duct. However, an ERCP showed a leakage of a subvesical bile duct arriving from the left hepatic duct. Diagnostic and treatment modalities are discussed.