TGF-ß signaling promotes desmoid tumor formation via CSRP2 upregulation.

Desmoid tumors (DTs), also called desmoid-type fibromatoses, are locally aggressive tumors of mesenchymal origin. In the present study, we developed a novel mouse model of DTs by inducing a local mutation in the Ctnnb1 gene, encoding ß-catenin in PDGFRA-positive stromal cells, by subcutaneous injection of 4-hydroxy-tamoxifen. Tumors in this model resembled histologically clinical samples from DT patients and showed strong phosphorylation of nuclear SMAD2. Knockout of SMAD4 in the model significantly suppressed tumor growth. Proteomic analysis revealed that SMAD4 knockout reduced the level of Cysteine-and-Glycine-Rich Protein 2 (CSRP2) in DTs, and treatment of DT-derived cells with a TGF-ß receptor inhibitor reduced CSRP2 RNA levels. Knockdown of CSRP2 in DT cells significantly suppressed their proliferation. These results indicate that the TGF-ß/CSRP2 axis is a potential therapeutic target for DTs downstream of TGF-ß signaling.

Development of Desmoid Tumors After Ileorectal Anastomosis Versus Ileal Pouch-Anal Anastomosis in Familial Adenomatous Polyposis.

BACKGROUND & AIMS: Desmoid tumors (DT) are an important cause of morbidity and mortality in patients with familial adenomatous polyposis (FAP). DT development might be related to the type and approach of colectomy. We aimed to compare DT development after colectomy with ileorectal anastomosis (IRA) and proctocolectomy with ileal pouch-anal anastomosis (IPAA). METHODS: We performed an international historical cohort study in patients with FAP who underwent IRA or IPAA between 1961 and 2020. The primary outcome was the incidence of abdominal DT (either mesenteric, retroperitoneal, or abdominal wall). Patients with a DT diagnosis before or at colectomy were excluded. Time to DT was considered censored at an eventual secondary proctectomy after IRA. We used multivariable Cox regression modelling to adjust for potential confounders. RESULTS: We analyzed data from 852 patients: 514 after IRA and 338 after IPAA (median follow-up, 21 and 16 years, respectively). DTs were diagnosed in 64 IRA patients (12%) and 66 IPAA patients (20%). The cumulative DT incidence at 5 and 10 years was 7.5% and 9.3% after open IRA and 4.7% and 10.9% after laparoscopic IRA. These estimates were 13.6% and 15.4% after open IPAA and 8.4% and 10.0% after laparoscopic IPAA. The postoperative risk was significantly higher after IPAA (P < .01) in multivariable analysis, whereas approach did not significantly influence the risk. CONCLUSIONS: The risk of developing an abdominal DT was found to be significantly higher after IPAA than after IRA. Postoperative DT risk should be taken into account when choosing between IRA and IPAA in FAP.

Evolution of Initial Treatment for Desmoid Tumors.

INTRODUCTION: Desmoid tumors (DTs) are rare, fibroblastic cell proliferations that can exhibit locally aggressive behavior but lack metastatic potential. Initial management has traditionally involved upfront resection; however, contemporary guidelines and expert panels have increasingly advocated for prioritizing active surveillance strategies. METHODS: A single-institution, retrospective chart review identified all patients diagnosed with a primary DT at any site from 2007 to 2020. The primary outcome was the initial management strategy over time. Secondary outcomes included treatment-free survival (TFS) and time to treatment (TTT) for those undergoing active surveillance, as well as recurrence-free survival (RFS) and time to recurrence for those undergoing resection. RESULTS: Overall, 103 patients were included, with 68% female and a median follow-up of 44 months [24-74]. The most common tumor locations included the abdominal wall (27%), intra-abdominal/mesenteric (25%), chest wall (19%), and extremity (10%). Initial management included resection (60%), systemic therapy (20%), active surveillance (18%), and cryoablation (2%). Rates of surgical resection significantly decreased (p < 0.001) over time, from 69.6% prior to 2018 to 29.2% after 2018. For those treated with upfront resection, 5-year RFS was 41.2%, and for patients undergoing initial active surveillance, TFS was 66.7% at 2 years, with a median TTT of 4 months [4-10]. CONCLUSIONS: This single-institution cohort at a tertiary medical center spanning over a decade demonstrates the transition to active surveillance for initial management of DTs, and highlights salient metrics in the era of surveillance. This trend mirrors recommended treatment strategies by expert panels and consensus guidelines.

Desmoid Tumors: Current Perspective and Treatment.

OPINION STATEMENT: Desmoid tumors are rare tumors with a tendency to infiltrate locally. The lack of a standard treatment approach makes choosing the most appropriate treatment for patients challenging. Most experts recommend watchful observation for asymptomatic patients as spontaneous regression of tumor is observed in up to 20% of patients. Upfront resection of the desmoid tumor has fallen out of favor due to high morbidity and high relapse rates associated with the tumor. Systemic therapy has evolved over several decades. Where chemotherapy, hormonal therapy, and non-steroidal anti-inflammatory drugs were used over the last several decades, tyrosine kinase inhibitors came to the forefront within the last decade. Most recently, gamma-secretase inhibitors have shown significant clinical benefit in patients with desmoid tumors, bringing forth an entirely new mechanistic approach. Several Wnt pathway inhibitors are also under development. Invasive approaches like cryoablation have also shown clinical benefit in patients with extra-abdominal desmoid tumors in recent years. The recent approval of nirogacestat has ushered in a new era of treatment for patients diagnosed with desmoid tumors. Several new molecules are expected to be approved over the coming years.

Favorable clinical efficacy of cytotoxic chemotherapy in patients with progressive desmoid tumors: a retrospective real-world study.

BACKGROUND: The real-world evidence about the efficacy of cytotoxic chemotherapy in desmoid tumors is still limited. We investigated the efficacy of chemotherapy in the treatment of recurrent or progressive desmoid tumors. METHODS: The patients with desmoid tumors who had received cytotoxic chemotherapy between November 2007 and June 2020 in two tertiary hospitals in Korea were reviewed. RESULTS: A total of 25 patients were included in the analysis. The most common primary tumor site was the intra-abdominal or pelvic cavity (56%), followed by the trunk and abdominal wall (24%), extremities (16%), and head and neck (4%). Sixty percent of the patients had familial adenomatous polyposis and 76% received doxorubicin plus dacarbazine. The objective response rate and disease control rate was 64% (95% confidence interval [CI]: 40.7-82.8) and 96% (95% CI: 77.2-99.9), respectively. With the median follow-up time of 55 months (95% CI: 41.0-68.2), the 3-year PFS rate was 65% (95% CI: 41.1-80.5), and the 3-year OS rate was 89% (95% CI: 63.8-97.3). Grade 3 or 4 hematologic adverse events were reported in 14 patients, all of which were manageable. CONCLUSION: Our real-world evidence suggests that doxorubicin-based cytotoxic chemotherapy can be an effective treatment option for recurrent and progressive desmoid tumors with respect to favorable clinical outcomes.

Update on Familial Adenomatous Polyposis-Associated Desmoid Tumors.

Desmoid tumors (DT) represent the second high risk of tumor in familial adenomatous polyposis (FAP) patients. Although FAP-associated DTs (FAP-DT) are caused by germline mutations in the adenomatous polyposis coli (APC) gene, extracolonic manifestations, sex, family history, genotype, and the ileal pouch anal anastomosis procedure are all linked to the development of DTs in FAP patients. Multidisciplinary management has replaced aggressive surgery as the preferred treatment of DTs. There is growing evidence to support the use of active surveillance strategy as first-line treatment for FAP-DT patients. Radiotherapy for intra-abdominal desmoids is now rarely used because of severe late toxicity. Pharmacotherapy, however, represents a promising future with the improvement of traditional cytotoxic drugs and the investigation of targeted drugs. Although nonsurgery treatment has been used widely nowadays, surgery remains the mainstay when symptomatic or life-threatening DTs are present. Further research will be needed for more optimal clinical practice.

Ultrasound-Guided Vacuum-assisted Biopsy Versus Surgical Resection in Patients With Breast Desmoid Tumor.

BACKGROUND: Recent studies suggest that desmoid tumors can be managed more conservatively rather than undergoing wide surgical resection (SR). Ultrasound-guided vacuum-assisted biopsy (UGVAB) is a minimally invasive technique. This retrospective study aimed to compare the outcome in patients with breast desmoid tumor (BDT) who received UGVAB alone versus SR. MATERIALS AND METHODS: The pathology database was searched for patients diagnosed with BDT ≤ 3 cm from 2007 to 2019. All patients underwent breast ultrasound examination and were then performed UGVAB alone or local SR. The Kaplan-Meier method with a log-rank test was used as a univariate analysis to compare the relapse-free survival (RFS) rates between UGVAB and SR groups. Cox regression analysis was used for multivariate analysis. RESULTS: A total of 39 patients were included. The median follow-up was 41 mo (range, 5-110 mo). The incidence of tumor recurrence was 23.1% (9/39). The 3-y cumulative RFS was 83.1% and 95.8% in the UGVAB and SR group, respectively, which was not significantly different between the two groups (P = 0.131, log-rank test). Multivariate analysis also revealed that treatment strategy (UGVAB versus SR) was not associated with an increased risk of relapse events (P = 0.274). CONCLUSIONS: Small desmoid tumors (≤3 cm) after UGVAB alone did not have a significantly compromised RFS compared with those who underwent SR. UGVAB may be an alternative and relatively conservative method for the diagnosis and local control of BDT with a smaller size. A prospective, randomized study with large sample size is needed to confirm this observation.

Does ileoanal pouch surgery increase the risk of desmoid in patients with familial adenomatous polyposis?

PURPOSE: Patients with familial adenomatous polyposis (FAP) may undergo either ileorectal anastomosis (IRA) or ileal pouch anal anastomosis (IPAA) depending on the degree of rectal involvement. Desmoid tumors (DTs) may arise postoperatively. Whether IPAA is associated with a higher risk of DTs as compared with IRA remains controversial. The purpose of this study was to determine whether IPAA increased the risk of DTs by analyzing the published data that compared IRA and IPAA as the primary treatment for FAP. METHODS: A metaanalysis was performed to analyze the published data between 1989 and 2019. IRA and IPAA were compared with respect to the incidence of DTs. RESULTS: Eight retrospective studies with a total of 1072 patients were identified: 491 underwent IPAA and 581 IRA. There was no significant difference in the incidence of DTs between IPAA and IRA (11.81% vs. 9.47%, OR 0.95, P = 0.85). Meanwhile, the overall complication (42.97% vs. 36.76%, OR 1.32, P = 0.11), incidence of cancer (4.88% vs. 8.37%, OR 0.28, P = 0.26), and overall mortality (0.33% vs. 5.20%, OR 0.49, P = 0.53) were comparable too. CONCLUSION: Ileoanal pouch surgery is associated with similar risk of desmoid in patients with FAP after surgery.

Definitive radiation therapy in patients with unresectable desmoid tumors: a systematic review.

BACKGROUND: Desmoid tumors are rare soft tissue tumors. Wide local excision has been the standard surgical treatment for desmoid tumors. However, this procedure results in high local recurrence rates, so non-surgical treatments should be considered. The aim of this systematic review was to evaluate the effect of radiation therapy on patients with desmoid tumors, especially those with unresectable disease. METHODS: We evaluated studies published between 1 January 1990 and 31 August 2017 and cited in PubMed and Ichushi (in Japanese). All studies evaluating the effect of radiation therapy on desmoid tumors were included. Data regarding radiation dose, recurrence and adverse events were recorded. RESULTS: Among 218 identified studies, only 6 were finally included in this review. Local control was achieved in 253 of 317 patients with unresectable or unresected tumors who underwent definitive radiation therapy (the crude rate of local control was 79.8%). Toxicity was evaluated in patients who underwent definitive radiation therapy or surgery plus radiation therapy. One of the most common acute complications was skin toxicity. Frequent late complications of radiation therapy included fibrosis/contracture/joint stiffness, skin disorders, lymphedema and pain. Six patients developed secondary malignancies in the radiation field. CONCLUSIONS: In patients treated unsuccessfully with surgery, watchful waiting and pharmacotherapy, radiation therapy may be an option as salvage therapy because of the high rate of local control. Because desmoid tumors frequently develop in young individuals, children and young patients who receive radiation therapy for the treatment of desmoid tumors should be followed up on a long-term basis with periodic monitoring for late radiation toxicities.

Autophagy inhibition overcomes sorafenib resistance in S45F-mutated desmoid tumors.

BACKGROUND: Desmoid tumors (DTs) are rare and understudied fibroblastic lesions that are frequently recurrent and locally invasive. DT patients often experience chronic pain, organ dysfunction, decrease in quality of life, and even death. METHODS: Sorafenib has emerged as a promising therapeutic strategy, which has led to the first randomized phase 3 clinical trial devoted to DTs. Concurrently, we conducted a comprehensive analysis of sorafenib efficacy in a large panel of desmoid cell strains to probe for response mechanism. RESULTS: We found distinctive groups of higher- and lower-responder cells. Clustering the lower-responder group, we observed that CTNNB1 mutation was determinant of outcome. Our results revealed that a lower dose of sorafenib was able to inhibit cell viability, migration, and invasion of wild-type and T41A-mutated DTs. Apoptosis induction was observed in those cells after treatment with sorafenib. On the other hand, the lower dose of sorafenib was not able to inhibit cell viability, migration, or invasion or to induce apoptosis in the S45F-mutated DTs. The investigation of autophagy showed the dependency of S45F-mutated DTs on this pathway as a part of cell survival mechanism. Significantly, when autophagy was inhibited genetically or pharmacologically in the S45F mutant cell strains, sensitivity to sorafenib was restored. CONCLUSIONS: Our findings suggest that the response to sorafenib differs when comparing S45F-mutated DTs and T41A-mutated or wild-type DTs. Furthermore, the combination of hydroxychloroquine and sorafenib enhances the antiproliferative and proapoptotic effects in S45F-mutated DT cells, suggesting that profiling ß-catenin status could guide clinical management of desmoid patients who are considering sorafenib treatment.

Desmoid tumors display a strong immune infiltration at the tumor margins and no PD-L1-driven immune suppression.

Desmoid tumors (DTs) are local aggressive neoplasms, whose therapeutic approach has remained so far unsolved and in many instances controversial. Nowadays, immunotherapy appears to play a leading role in the treatment of various tumor types. Characterization of the tumor immune microenvironment (TME) and immune checkpoints can possibly help identify new immunotherapeutic targets for DTs. We performed immunohistochemistry (IHC) on 33 formalin-fixed paraffin-embedded (FFPE) tissue sections from DT samples to characterize the TME and the immune checkpoint expression profile. We stained for CD3, CD4, CD8, CD20, FoxP3, CD45RO, CD56, CD68, NKp46, granzyme B, CD27, CD70, PD1 and PD-L1. We investigated the expression of the markers in the tumoral stroma, as well as at the periphery of the tumor. We found that most of the tumors showed organization of lymphocytes into lymphoid aggregates at the periphery of the tumor, strongly resembling tertiary lymphoid organs (TLOs). The tumor expressed a significant number of memory T cells, both at the periphery and in the tumoral stroma. In the lymphoid aggregates, we also recognized a significant proportion of regulatory T cells. The immune checkpoint ligand PD-L1 was negative on the tumor cells in almost all samples. On the other hand, PD1 was partially expressed in lymphocytes at the periphery of the tumor. To conclude, we are the first to show that DTs display a strong immune infiltration at the tumor margins, with formation of lymphoid aggregates. Moreover, we demonstrated that there is no PD-L1-driven immune suppression present in the tumor cells.

Radiotherapy in the treatment of primary or recurrent unresectable desmoid tumors of the neck.

Purpose: Desmoid tumors are locally aggressive nonmalignant soft tissue tumors, which frequently recur after therapy. The optimal treatment is still controversial because of the lack of large research. A few studies have reported the effects of other treatments in one lesion when surgery is not possible or would cause notable functional impairment. Our aim was to examine the outcome of radiotherapy (RT) in the treatment of primary or recurrent unresectable desmoid tumors of the neck. Materials: A retrospective analysis was performed on 30 patients between 1/2008 and 12/2017, with 3 primary and 27 recurrent unresectable desmoid tumors of the neck. All cases were reviewed by pathologists. Results: The median follow-up time was 50.5 months (range 2-126 months). Radiotherapy doses varied from 50 to 66 Gy (median 60 Gy, 23/30 patients) with all fraction size of 2 Gy. The objective response rate (ORR: CR or PR) to definitive RT was 56.7% (17/30 patients). On Chi-square statistic, ORR was significantly influenced by tumor size (≤5 cm versus >5 cm) (p = .046). Age (≤ 40 versus >40 years) (p = .804), gender (p = .629), and RT dose (≤60 versus >60 Gy) (p = .613) were not significantly associated with ORR. The most common acute side effects of the radiation-related complication were grade 1-2 skin toxicities. Conclusion: Radiotherapy is a valuable option in the management of primary or recurrent unresectable DTs of the neck with good local control. Multi-institutional and prospective studies are warranted to further validate our findings.

The impact of technical parameters on ablation volume during MR-guided focused ultrasound of desmoid tumors.

PURPOSE: Desmoid tumors are benign, locally aggressive soft tissue tumors derived from fibroblasts. Magnetic resonance-guided focused ultrasound (MRgFUS) is a safe and effective treatment for desmoid tumors. The purpose of this study was to retrospectively review the MRgFUS treatments of desmoid tumors at our institution to determine which technical treatment parameters contributed most significantly to the accumulation of thermal dose. MATERIALS AND METHODS: The study protocol was approved by the local IRB. We retrospectively reviewed data from MRgFUS treatments performed in histologically-confirmed desmoid tumors, over a period of 18 months. Sonication parameter means were compared with ANOVA. Mixed effects and linear regression models were used to evaluate the relative contribution of different parameters to thermal dose volume. RESULTS: Nine-hundred thirty-six sonications were reviewed in 13 treatments. Accumulated dose per sonication was greatest for elongated sonications (0.96 cc ± 0.90) compared to short (0.88 ± 0.93 cc) and nominal (0.55 ± 0.70 cc) sonications, p < .001. 65.2% of short sonications resulted in high percentage ablations, compared to 46.0% of nominal and 35.1% of elongated sonications. Standardized beta coefficients (anticipated increased volume in cc per unit) for power, duration, energy and average temperature were 0.006, 0.057, 0.00035 and 0.03, p < .001. Regarding dose efficacy, dose area contributed the greatest to this variability - 50.7% (45.5-54.8%), followed by distance - 16.6% (12.9-20.0%). CONCLUSIONS: A variety of sonication parameters significantly contributed to thermal ablation volume following MRgFUS of desmoid tumors, in reproducible patterns. This work can serve as the basis for future models working toward improved planning for MRgFUS treatments.

T2 mapping as a predictor of nonperfused volume in MRgFUS treatment of desmoid tumors.

Objective: The objective of this study was to develop an alternative method of non-contrast monitoring of tissue ablation during focused ultrasound treatment. Desmoid tumors are benign but locally aggressive soft tissue tumors that arise from fibroblast cells. Magnetic resonance-guided focused ultrasound (MRgFUS) has emerged as an alternative to conventional therapies, showing promising results in reduction of tumor volume without significant side effects. The gold-standard assessment of the reduction of viable tumor volume post-treatment is non-perfused volume (NPV) and evaluation of NPV is typically performed with post-treatment gadolinium enhanced MR imaging. However, as gadolinium cannot be repeatedly administered during treatments, there is a need for alternative non-contrast monitoring of the tissue to prevent over and under treatment. Methods: Double-echo and multi-echo images were acquired before, during and after the MRgFUS treatment. T2 maps were generated with an exponential fit and T2 maps were compared to post-treatment post-contrast images.Results: In all five MRgFUS treatment sessions, T2 mapping showed excellent qualitative agreement with the post-contrast NPV.Conclusions: T2 mapping may be used to visualize the extent of ablation with focused ultrasound and can be used as a predictor of NPV prior to the administration of contrast during the post-treatment assessment.

TALENs and CRISPR/Cas9 fuel genetically engineered clinically relevant Xenopus tropicalis tumor models.

The targeted nuclease revolution (TALENs, CRISPR/Cas9) now allows Xenopus researchers to rapidly generate custom on-demand genetic knockout models. These novel methods to perform reverse genetics are unprecedented and are fueling a wide array of human disease models within the aquatic diploid model organism Xenopus tropicalis (X. tropicalis). This emerging technology review focuses on the tools to rapidly generate genetically engineered X. tropicalis models (GEXM), with a focus on establishment of genuine genetic and clinically relevant cancer models. We believe that due to particular advantageous characteristics, outlined within this review, GEXM will become a valuable alternative animal model for modeling human cancer. Furthermore, we provide perspectives of how GEXM will be used as a platform for elucidation of novel therapeutic targets and for preclinical drug validation. Finally, we also discuss some future prospects on how the recent expansions and adaptations of the CRISPR/Cas9 toolbox might influence and push forward X. tropicalis cancer research.

Multiple rapidly growing desmoid tumors that were difficult to distinguish from recurrence of rectal cancer.

BACKGROUND: Intra-abdominal desmoid tumors are usually slow growing and solitary, but multifocal desmoid tumors develop on rare occasions. Diagnosing desmoid tumors before histological examination of a surgical biopsy is often difficult. In particular, if a patient has a prior history of malignancy, it may be difficult to differentiate between these lesions and disease recurrence or metastasis. CASE PRESENTATION: We present a rare case of multiple rapidly growing intra-abdominal desmoid tumors after surgical trauma, without familial adenomatous polyposis. A 51-year-old male underwent abdominal perineal resection with lateral lymph node dissection after neoadjuvant chemotherapy for lower rectal cancer. Follow-up computed tomography (CT), performed 6 months after primary surgery, showed a 20-mm solitary mass in the pelvic mesentery. Another CT scan, performed 3 months later, revealed that the mass had grown to 35 mm in size and that two new masses had formed. Based on imaging studies and his medical history, it was difficult to distinguish the desmoid tumors from recurrence of rectal cancer. Curative resection was chosen for therapeutic diagnosis. The pathological diagnosis was multiple mesenteric desmoid tumors. CONCLUSIONS: Desmoid tumors should not be excluded as a differential diagnosis for intra-abdominal masses after intra-abdominal surgery, even in cases of rapidly growing multiple masses.

Conservative management of desmoid tumors is safe and effective.

BACKGROUND: Surgical resection of desmoid tumors has traditionally been the mainstay of therapy, but this is a potentially morbid approach with high rates of recurrence. Given increasing reports of active surveillance in this disease, we sought to evaluate our experience with conservative management hypothesizing this would be an effective strategy. MATERIALS AND METHODS: Using a prospectively maintained database of sarcoma patients from 2008 to 2015, we identified 47 patients with a diagnosis of desmoid tumor from all anatomic sites. Data points were abstracted on clinical and pathologic factors, disease stability or progression, and follow-up time. Main outcome measurements were tumor recurrence after surgical resection versus tumor progression with conservative management. RESULTS: In our cohort, 20 patients were managed with surveillance, 24 patients with surgery, and three patients with other approaches. Clinical and tumor characteristics between treatment groups were not significantly different. With a median follow-up of 35.7 mo, there was one complete regression, five partial regressions, and 13 stable diseases among the surveillance group. Only one patient under observation progressed, crossing over to surgical resection. Among 24 patients managed with surgery, 13 patients developed local recurrence. Kaplan-Meier analysis revealed a statistically superior progression-free survival in the surveillance group (P = 0.001). CONCLUSIONS: This retrospective analysis adds to the growing body of evidence that observation of desmoid tumors is safe and effective with high rates of stable disease. These data further support an initial conservative approach to desmoid tumors that may spare patients the morbidity and risk of recurrence that accompanies potentially extensive operations.

Intestinal perforation during chemotherapeutic treatment of intra-abdominal desmoid tumor in patients with Gardner's syndrome: report of two cases.

BACKGROUND: A minority of intra-abdominal desmoid tumors is associated with Gardner's syndrome in which desmoid tumors become an important cause of morbidity and mortality if they are surgically unresectable. CASE PRESENTATION: Here, we report two cases of intestinal perforation during chemotherapy in patients with Gardner's syndrome-associated intra-abdominal desmoids. One female and one male patients who developed inoperable desmoids were given the chemotherapeutic regimen of doxorubicin plus dacarbazine, followed by meloxicam. Significant tumor regression was observed clinically. However, intestinal perforation happened in both patients. They were subjected to emergency surgery, follow-up management, and survived up to now. CONCLUSIONS: The doxorubicin plus dacarbazine chemotherapy is an effective treatment for intra-abdominal demoid tumors in patients with Gardner's syndrome. On the other hand, given severe adverse events might occur, clinicians should pay more attention that tumor quick regression may cause intestinal perforation in which urgent surgical intervention is necessary.

Targeting the Notch pathway: A potential therapeutic approach for desmoid tumors.

BACKGROUND: Desmoid tumors (DTs) are rare mesenchymal lesions that can recur repeatedly. When it is feasible, DTs are surgically resected; however, this often results in high recurrence rates. Recently, treatment with PF-03084014, a potent γ-secretase inhibitor, has been shown to have antitumor activity in several tumor types by affecting the WNT/ß-catenin pathway. Consequently, Notch pathway inhibition by PF-03084014 might be a promising approach for DT treatment. METHODS: The expression of Notch pathway components was analyzed in DT tissues and cell strains with immunohistochemistry and Western blotting, respectively. A panel of DT cell strains was exposed to PF-03084014 and evaluated for cell proliferation. Antitumor effects were assessed via cell cycle, apoptosis, and migration and invasion analysis. Cells treated with PF-03084014 were characterized with a gene array analysis combined with Ingenuity Pathway Analysis. RESULTS: The results showed that Notch pathway components were expressed at different levels in DTs. Hes1 (Hes Family BHLH Transcription Factor 1) was overexpressed in DT tumors versus dermal scar tissue, and PF-03084014 caused significant decreases in Notch intracellular domain and Hes1 expression in DT cell strains. PF-03084014 decreased DT cell migration and invasion and also caused cell growth inhibition in DT cell strains, most likely through cell cycle arrest. Gene array analysis combined with Ingenuity Pathway Analysis showed that Wnt1-inducible signaling pathway protein 2 possibly regulated Notch and WNT pathways after treatment with PF-03084014 through integrin. CONCLUSION: Our findings suggest that the Notch pathway is an important DT therapeutic target. Furthermore, PF-03084014 has significant antitumor activity against DTs, and it may be an alternative strategy for DT treatment.

Desmoid tumors of the upper extremity.

PURPOSE: To determine the outcomes of surgical excision with or without adjuvant treatment in the management of desmoid tumors of the upper extremity. METHODS: We retrospectively reviewed 52 patients with a histologically confirmed desmoid tumor in the upper extremity that was managed surgically. All patients presented between 1970 and 2011 and had a minimum 2-year follow-up. RESULTS: There were 25 males and 27 females with an average age of 37 ± 17 years. The most common location was the shoulder (n = 27). The most common symptom was a painful mass (n = 30). Average tumor size was 189 ± 371 cm(3). Negative margins (wide or marginal resection) were achieved in 43 patients. The 5-year disease-free interval was 57%. Patients with recurrence were younger than those without (31 vs 43 y). Postoperative radiotherapy increased the time to recurrence (2.6 vs 1.6 y) but ultimate disease-free interval at 5 years was similar in patients who did and did not receive radiotherapy. Compared with the preoperative evaluation, there was a significant reduction in patients reporting moderate or severe pain postoperatively. CONCLUSIONS: Desmoid tumors are locally aggressive fibrous tumors. Recurrence after surgical excision of a desmoid tumor in the upper extremity is common, especially in younger patients. Adjuvant radiation therapy tended to increase time to recurrence but not rate of recurrence. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.