Superficial fibromas with CTNNB1 mutation.

Superficial fibromas are a group of mesenchymal spindle cell lesions with pathomorphological heterogeneity and diverse molecular backgrounds. In part, they may be indicators of an underlying syndrome. Among the best-known entities of superficial fibromas is Gardner fibroma, a plaque-like benign tumor, which is associated with APC germline mutations and occurs in patients with familial adenomatosis polyposis (Gardner syndrome). Affected patients also have an increased risk to develop desmoid fibromatosis (DTF), a locally aggressive neoplasm of the deep soft tissue highly prone to local recurrences. Although a minority of DTFs occur in the syndromic context and harbor APC germline mutations, most frequently their underlying molecular aberration is a sporadic mutation in Exon 3 of the CTNNB1 gene. Up to date, a non-syndromic equivalent to Gardner fibroma carrying a CTNNB1 mutation has not been defined. Here, we present two cases of (sub-)cutaneous tumors with a hypocellular and collagen-rich Gardner fibroma-like appearance and pathogenic, somatic CTNNB1 mutations. We aim to differentiate these tumors from other fibromas according to their histological appearance, immunohistochemical staining profile and underlying somatic CTNNB1 mutations. Furthermore, we distinguish them from locally aggressive desmoid fibromatosis regarding their biological behavior, prognosis and indicated therapeutic strategies. Consequently, we call them CTNNB1-mutated superficial fibromas as a sporadic counterpart lesion to syndromic Gardner fibromas.

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.

Trauma and sporadic desmoid tumor development: An approach toward real incidence and aspects of causality.

OBJECTIVES: The development of desmoid tumors (DT) is associated with trauma, which is an aspect with medicolegal relevance. The objective of this study was to analyze the proportion and type of trauma (surgical, blunt/fracture, implants), its lag time, and mutations of the CTNNB1 gene in patients with sporadic DT. METHODS: We analyzed a prospectively kept database of 381 females and 171 males, median age at disease onset 37.7 years (females) and 39.3 years (males) with a histologically confirmed DT. Patients with germline mutation of the APC gene were excluded. Details of the history particularly of traumatic injuries to the site of DT were provided by 501 patients. RESULTS: In 164 patients (32.7%), a trauma anteceding DT could be verified with a median lag time of 22.9 months (SD, 7.7 months; range, 9-44 months). A prior surgical procedure was relevant in 98 patients, a blunt trauma in 35 patients, a punctuated trauma (injections, trocar) in 18 patients, and site of an implant in 10 patients. In 220 patients, no trauma was reported (43.9%), and 58 females (11.6%) had a postpregnancy DT in the rectus abdominis muscle. In 42 patients (8.4%), data were inconclusive. The distribution of mutations in the CTNNB1 gene (codon 41 vs. 45) was similar in patients with and without a history of trauma before DT development. CONCLUSIONS: A significant subgroup of patients suffers from a trauma-associated DT, predominantly at a prior surgical site including implants to breast or groin, accounting for 77.9% of the cases, whereas blunt trauma was responsible in 22.1%. We found no data to support that trauma-associated DT have different molecular features in the CTNNB1 gene.

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.

Circulating Tumor DNA in Patients with Desmoid Fibromatosis during Active Surveillance.

BACKGROUND: Sporadic desmoid fibromatosis (DF) is a rare locally aggressive tumor characterized by mutation in exon 3 of CTNNB1 (T41A, S45F, and S45P). Standard of care is active surveillance (AS), but 30% require treatment. DF clinical course is unpredictable and identification of prognostic markers is needed to tailor strategy. In this prospective study, we investigated the consistency between mutation detected in tumor biopsies with that detected in plasma by digital droplet PCR (ddPCR) and the association between circulating tumor DNA (ctDNA) abundancy with clinical outcome. PATIENTS AND METHODS: A total of 56 patients and 10 healthy donors were included. CTNNB1 mutation status of DF biopsies was determined by Sanger and in case of WT CTNNB1 with NGS. In matched plasma samples at enrollment and during AS at specific timepoints, we evaluated cfDNA quantity and ctDNA. RESULTS: ctDNA levels were measured in 46 patients with CTNNB1 mutation. Detection rate for T41A, S45F and S45P was 68%, 42% and 100%, respectively. S45P variant has been detected in all patients with S45P mutation. Longitudinal assessment of ctDNA during AS in nine patients (four with regression and five with progression as first event according to RECIST) showed a concordance between the event and ctDNA level change in six out of nine patients tested (4/5 with progression and 2/4 with regression). CONCLUSIONS: Results of ctDNA analysis support its potential clinical implementation as diagnostic tool in specific clinical scenarios where biopsy can be challenging. A prospective clinical trial needs to be performed to evaluate the potential role of ctDNA as predictive biomarker.

Setting the international research agenda for sarcomas with patients and carers: results of phase II of the Sarcoma Patient Advocacy Global Network (SPAGN) priority setting partnership.

BACKGROUND: Typically, researchers and clinicians determine the agenda in sarcoma research. However, patient involvement can have a meaningful impact on research. Therefore, the Patient-Powered Research Network (PPRN) of the Sarcoma Patient Advocacy Global Network (SPAGN) set up a Priority Setting Partnership (PSP). The primary objective of this partnership is to identify priorities for research and patient advocacy topics. METHODS: In the first phase of this PSP, including 264 sarcoma patients and carers from all over the world, 23 research topics regarding sarcomas and 15 patient advocacy topics were identified using an online survey. In the second phase, participants were asked to fill in a top five and a top three of research and patient advocacy topics, respectively. Additionally, sociodemographic characteristics and sarcoma characteristics were collected. Social media channels, local national patient advocacy groups and the SPAGN website were used to distribute the survey. RESULTS: In total, 671 patients (75%) and carers (25%) participated in this survey. The five highest ranked research topics were related to causes of sarcoma (43%), prognosis and risk of recurrence (40%), specific subtypes of sarcoma (33%), the role of immunotherapy, targeted therapy and combined therapy (30%), and hereditary aspects (30%). The three highest ranked patient advocacy topics were improving the diagnostic process of sarcoma (39%), access to tumor DNA analysis (37%) and establishing an international sarcoma registry (37%). CONCLUSIONS: This sarcoma PSP has identified priorities for research and patient advocacy, offering guidance for researchers, assisting funding agencies with assessing project relevance and empowering patient advocates to represent the needs of patients and carers.

Risk factors for local recurrence of upper extremity desmoid tumors.

INTRODUCTION: Upper extremity (UE) desmoid tumors are locally aggressive neoplasms with high recurrence rates. Our study sought to analyze the demographics and treatment strategies of UE desmoid tumors and identify risk factors for recurrence. MATERIALS AND METHODS: A retrospective review of 52 patients with histologically confirmed UE desmoid tumors treated at our institution between 1990 and 2015 was conducted. Survival was assessed using the Kaplan-Meier method and the Cox proportional hazards model was used for risk factor analysis. RESULTS: For the entire cohort, median age was 40 (29-47) years, 75% were female, and 48% had local recurrence. The median tumor size was 45 (15-111) cm3 on imaging. Twenty-two patients had a previous resection. The most common treatments were surgery alone (50%) and surgery with adjuvant radiotherapy (21%). Tumor size ≥5 cm and tumor volume ≥40 cm3 on imaging were associated with increased recurrence (p = 0.006 and p = 0.005, respectively). Age and sex were not associated with local recurrence. Patients with a tumor size ≥5 cm were 2.6 times more likely to present with recurrence. At the 10-year mark, a lower local recurrence-free survival was seen in patients with tumors ≥5 cm (72.2% vs. 36.3%, p = 0.042) or ≥40 cm3 (67.2% vs. 32.7%, p = 0.034). CONCLUSION: In our study, only tumor dimensions appeared to modify recurrence risk.

Update on Percutaneous Ablation for Sarcoma.

PURPOSE OF REVIEW: To provide an update on the current state of percutaneous thermal ablation in the treatment of sarcoma. RECENT FINDINGS: Data continue to accrue in support of ablation for local control and palliation of specific sarcoma subtypes such as extra-abdominal desmoid fibromatosis and for broader indications such as the treatment of oligometastatic disease. The synergistic possibilities of various combination therapies such as cryoablation and immunotherapy represent intriguing areas of active investigation. Histotripsy is an emerging non-invasive, non-thermal ablative modality that may further expand the therapeutic arsenal for sarcoma treatment. Percutaneous thermal ablation is a valuable tool in the multidisciplinary management of sarcoma, offering a minimally invasive adjunct to surgery and radiation therapy. Although there remains a paucity of high-level evidence specific to sarcomas, ablation techniques are demonstrably safe and effective for achieving local tumor control and providing pain relief in select patients and are of particular benefit in those with metastatic disease or requiring palliative care.

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.

CRISPR-SID: Identifying EZH2 as a druggable target for desmoid tumors via in vivo dependency mapping.

Cancer precision medicine implies identification of tumor-specific vulnerabilities associated with defined oncogenic pathways. Desmoid tumors are soft-tissue neoplasms strictly driven by Wnt signaling network hyperactivation. Despite this clearly defined genetic etiology and the strict and unique implication of the Wnt/ß-catenin pathway, no specific molecular targets for these tumors have been identified. To address this caveat, we developed fast, efficient, and penetrant genetic Xenopus tropicalis desmoid tumor models to identify and characterize drug targets. We used multiplexed CRISPR/Cas9 genome editing in these models to simultaneously target a tumor suppressor gene (apc) and candidate dependency genes. Our methodology CRISPR/Cas9 selection-mediated identification of dependencies (CRISPR-SID) uses calculated deviations between experimentally observed gene editing outcomes and deep-learning-predicted double-strand break repair patterns to identify genes under negative selection during tumorigenesis. This revealed EZH2 and SUZ12, both encoding polycomb repressive complex 2 components, and the transcription factor CREB3L1 as genetic dependencies for desmoid tumors. In vivo EZH2 inhibition by Tazemetostat induced partial regression of established autochthonous tumors. In vitro models of patient desmoid tumor cells revealed a direct effect of Tazemetostat on Wnt pathway activity. CRISPR-SID represents a potent approach for in vivo mapping of tumor vulnerabilities and drug target identification.

Sclerosing well-differentiated liposarcoma: two diagnostically challenging mimicker cases and a literature review.

Liposarcoma is a malignant soft tissue tumor with several subtypes, the most common of which is well-differentiated liposarcoma (WDL) or atypical lipomatous tumor (ALT). WDL/ALTs are further divided into three histological subtypes, including lipoma-like, sclerosing, and inflammatory. While the majority of these tumors are predominantly fatty, the sclerosing variant demonstrates diverse histologic and radiographic characteristics, including variable amounts of fibrosis and fat. Because of this histological variability and relative rarity, the sclerosing WDL/ALT can present diagnostic dilemmas. We present two cases of sclerosing WDL/ALT, both of which demonstrated high degrees of fibrosis and a paucity of fat, mimicking desmoid fibromatosis and other fibrotic soft tissue tumors. Thus, it is important for radiologists to be aware of the subtypes of liposarcoma and their unique characteristics, and to consider sclerosing WDL/ALT in cases of fibrotic soft tissue tumors.

Update on musculoskeletal applications of magnetic resonance-guided focused ultrasound.

Magnetic resonance-guided focused ultrasound (MRgFUS) is a noninvasive, incisionless, radiation-free technology used to ablate tissue deep within the body. This technique has gained increased popularity following FDA approval for treatment of pain related to bone metastases and limited approval for treatment of osteoid osteoma. MRgFUS delivers superior visualization of soft tissue targets in unlimited imaging planes and precision in targeting and delivery of thermal dose which is all provided during real-time monitoring using MR thermometry. This paper provides an overview of the common musculoskeletal applications of MRgFUS along with updates on clinical outcomes and discussion of future applications.

Desmoid fibromatosis-a diagnostic dilemma.

PURPOSE: Desmoid fibromatosis in head and neck is infrequent and poses a significant challenge to the clinicians due to its non-specific characteristics. METHODS: This case report focuses on a 69-year-old male who presented to a tertiary healthcare center in Karnataka, India with a swelling in the oral cavity. RESULTS: Despite initial suspicions of malignancy based on clinical examination and findings on computed tomography imaging, subsequent histopathology and immunohistochemistry revealed an unexpected finding. CONCLUSION: The case highlights the importance of clinical suspicion and histopathological evaluation as well as the need for greater awareness to facilitate early diagnosis and appropriate management of desmoid fibromatosis. We also present a literature review of varied presentations of desmoid tumors afflicting various subsites of the head and neck.

Management of Desmoid Disease in Familial Adenomatous Polyposis.

Desmoid disease, though technically a benign condition, is nevertheless a leading cause of morbidity and mortality in patients with familial adenomatous polyposis (FAP). Desmoid disease impacts approximately 30% of FAP patients, with several known risk factors. It runs the gamut in terms of severity-ranging from small, slow-growing asymptomatic lesions to large, focally destructive, life-threatening masses. Desmoids usually occur following surgery, and several patient risk factors have been established, including female sex, family history of desmoid disease, 3' APC mutation, and extraintestinal manifestations of FAP. Desmoid disease-directed therapy is individualized and impacted by desmoid stage, severity, postsurgical anatomy, and consequences of disease. Medical therapy consists of options in multiple classes of drugs: nonsteroidal anti-inflammatory drugs, hormonal therapy, tyrosine kinase inhibitors, and cytotoxic agents. Surgical excision is sometimes an option, but can be limited by common location of disease at the root of the small bowel mesentery. Palliative surgical treatments are often considered in management of desmoid disease. Intestinal transplantation for severe desmoid disease is an emerging and promising option, though long-term data on efficacy and survival is limited.

Surgical Decision-Making in Familial Adenomatous Polyposis.

Familial adenomatous polyposis (FAP) is an autosomal dominant disorder affecting patients with germline mutations of the adenomatous polyposis coli (APC) tumor suppressor gene. The surgical treatment of colorectal disease in FAP, which has the goal of colorectal cancer prevention, varies based on both patient and disease factors but can include the following: total colectomy with ileorectal anastomosis, proctocolectomy with stapled or hand-sewn ileal pouch-anal anastomosis, or total proctocolectomy with end ileostomy. The operative options and extent of resection, as well as the use of endoscopy and chemoprevention for the management of polyposis, will be discussed in detail in this article. In addition, commonly debated management decisions related to the treatment of patients with FAP, including the timing of prophylactic colorectal resections for patients with FAP and management of the polyp burden in the rectum, will be discussed. Finally, genotype considerations and the impact of desmoid disease on operative decisions in the setting of FAP will also be reviewed.

The variable histogenesis and biology of selected bland fibroblastic lesions of the breast - pitfalls in the differential diagnostics and optimal therapeutic approach (three case reports).

Presented are three casuistics of seemingly identical breast lesions which even by adopting advanced laboratory techniques may represent diagnostic challenge. Microscopic features of some bland spindle cell lesions of different histogenesis (epithelial or mesenchymal) are misleading and a potential source of unaware errors, which might affect optimal therapeutic strategy. In the setting of three diverse entities (low-grade spindle cell metaplastic carcinoma, desmoid fibromatosis and phyllodes tumor) is documented both demanding diagnostic algorithm and revealing molecular landscape on one side as well as evolving predictive/prognostic parameters on the other one. Close interdisciplinary cooperation is inevitable for accurate interpretation/understanding of revealed diagnostic facts which is required for adjustment of competent rational and individualized therapy.

Pain in desmoid-type fibromatosis: Prevalence, determinants and prognosis value.

The aim of this study is to evaluate the prevalence, determinants and prognostic value of pain at diagnosis in patients with desmoid-type fibromatosis (DF). We selected patients from the ALTITUDES cohort (NCT02867033), managed by surgery, active surveillance or systemic treatments, with pain assessment at diagnosis. Patients were invited to fill QLQ-C30 questionnaire and Hospital Anxiety Depression Scale. Determinants were identified using logistic models. Prognostic value on event-free survival (EFS) was evaluated using the Cox model. Overall, 382 patients were included in the current study (median age: 40.2 years; 117 men). The prevalence of pain was 36%, without significant difference according to first-line treatment (P = .18). In the multivariate analysis, pain was significantly associated with tumor size >50 mm (P = .013) and tumor site (P < .001); pain was more frequent in the neck and shoulder locations (odds ratio: 3.05 [1.27-7.29]). Pain at baseline was significantly associated with poor quality of life (P < .001), depression (P = .02), lower performance status (P = .03) and functional impairment (P = .001); we also observed a nonsignificant association with anxiety (P = .10). In the univariate analysis, baseline pain was associated with poor EFS; the 3-year EFS was 54% in patients with pain compared to 72% in those without pain. After adjustment for sex, age, size and line of treatment, pain was still associated with poor EFS (hazard ratio: 1.82 [1.23-2.68], P = .003). One third of recently diagnosed patients with DF experienced pain, especially those with larger tumors and neck/shoulder locations. Pain was associated with unfavorable EFS after adjustment for the confounders.

Genotype-phenotype correlation for extracolonic aggressive phenotypes in patients with familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) patients develop various life-threatening extracolonic comorbidities that appear individually or within a family. This diversity can be explained by the localization of the adenomatous polyposis coli (APC) variant, but few reports provide definitive findings about genotype-phenotype correlations. Therefore, we investigated FAP patients and the association between the severe phenotypes and APC variants. Of 247 FAP patients, 126 patients from 85 families identified to have APC germline variant sites were extracted. These sites were divided into six groups (Regions A to F), and the frequency of severe comorbidities was compared among the patient phenotypes. Of the 126 patients, the proportions of patients with desmoid tumor stage ≥III, number of FGPs ≥1000, multiple gastric neoplasms, gastric neoplasm with high-grade dysplasia, and Spigelman stage ≥III were 3%, 16%, 21%, 12%, and 41%, respectively, while the corresponding rates were 30%, 50%, 70%, 50%, and 80% in patients with Region E (codons 1398-1580) variants. These latter rates were significantly higher than those for patients with variants in other regions. Moreover, the proportion of patients with all three indicators (desmoid tumor stage ≥III, number of FGPs ≥1000, and Spigelman stage ≥III) was 20% for those with variants in Region E and 0% for those with variants in other regions. Variants in Region E indicate aggressive phenotypes, and more intensive management is required.