Evaluation of eight melanocytic and neural crest-associated markers in a well-characterised series of 124 malignant peripheral nerve sheath tumours (MPNST): useful to distinguish MPNST from melanoma?

AIMS

The diagnosis of malignant peripheral nerve sheath tumour (MPNST) may be challenging, especially in the sporadic setting. Owing to the lack of specific histological criteria, immunohistochemical and molecular diagnostic markers, several differential diagnoses must be considered, especially melanoma. Indeed, although S100 protein usually stains melanoma, other melanocytic markers are often negative, especially in spindle cell/desmoplastic types. This pattern of immunoreactivity resembles that of some nerve-derived tumours such as MPNST. Owing to their different clinical behaviours and therapeutic implications, accurate identification of these two different tumours is crucial.

METHODS AND RESULTS

S100, SOX10, KBA62, MITF, HMB45, Melan-A, tyrosinase PNL2 and BRAF-V600E immunostaining was performed in a pathologically and genetically well-characterised cohort of primary MPNST (n = 124), including 66 (53%) NF1-associated tumours. Sox10 and KBA62 expression were found, respectively, in 102 (84%) and in 101 (83%) MPNST, whereas S100 was expressed in 64 cases (52%). We observed an increased loss of S100 with increasing histological grade (P = 0.0052). We found Melan-A expression in 14% (n = 17) of all MPNST, occurring in 82% (n = 14) of cases in an NF1 context. Six per cent (n = 8) of MPNST showed tyrosinase positivity, including seven (87%) NF1-associated. MITF expression was found in 10 (8%) MPNST. None expressed PNL2, HMB45 or BRAF-V600E.

CONCLUSION

MPNST (in NF1 and a sporadic setting) can quite often be positive for Melan-A, tyrosinase and MITF. Pathologists should be cognisant of these exceptions to prevent confusion with melanoma.

Maximum Lyapunov exponent revisited: Long-term attractor divergence of gait dynamics is highly sensitive to the noise structure of stride intervals

BACKGROUND

The local dynamic stability method (maximum Lyapunov exponent) can assess gait stability. Two variants of the method exist: the short-term divergence exponent (DE), and the long-term DE. Only the short-term DE can predict fall risk. However, the significance of long-term DE has been unclear so far. Some studies have suggested that the complex, fractal-like structure of fluctuations among consecutive strides correlates with long-term DE. The aim, therefore, was to assess whether the long-term DE is a gait complexity index.

METHODS

The study reanalyzed a dataset of trunk accelerations from 100 healthy adults walking at preferred speed on a treadmill for 10 min. By interpolation, the stride intervals were modified within the acceleration signals for the purpose of conserving the original shape of the signal, while imposing a known stride-to-stride fluctuation structure. Four types of hybrid signals with different noise structures were built: constant, anti-correlated, random, and correlated (fractal). Short- and long-term DEs were then computed.

RESULTS

The results show that long-term DEs, but not short-term DEs, are sensitive to the noise structure of stride intervals. For example, it was that observed that random hybrid signals exhibited significantly lower long-term DEs than hybrid correlated signals did (0.100 vs 0.144, i.e. a 44% difference). Long-term DEs from constant hybrid signals were close to zero (0.006). Conversely, short-term DEs of anti-correlated, random, and correlated hybrid signals were closely grouped (2.49, 2.50, and 2.51).

CONCLUSIONS

The short-term DE and the long-term DE, although they are both computed from divergence curves, should not be interpreted in a similar way. The long-term DE is very likely an index of gait complexity, which may be associated with gait automaticity or cautiousness. Consequently, to better differentiate between short- and long-term DEs, the use of the term attractor complexity index (ACI) is proposed for the latter.

Intra-rater reliability of hip abductor isometric strength testing in a standing position in older fallers and non-fallers

Background

Reduced hip muscle strength has been shown to be a major factor related to falls in older persons. However, comprehensive assessment of hip abduction strength in the clinical setting is challenging. The aim of this study was to investigate the feasibility and intra-rater reliability of a quick and simple hip abductor strength test in a functional standing position.

Methods

Individuals over 65 years of age were recruited from the geriatric department of a university hospital and an outpatient clinic. Thirty-two older subjects, including 16 fallers (≥1 fall during the last 12 months) and 16 non-fallers were included. Maximum voluntary isometric strength (MVIS) and rate of force generation (RFG) of the hip abductors of the right leg were evaluated in a standing position using a hand-held dynamometer. Two test-sessions were carried out. All hip strength values were normalized to participants’ weight. Reliability was determined using the intra-class correlation coefficient agreement (ICC_agreement), the standard error of measurement (SEM) and a Bland and Altman analysis (BA).

Results

All participants completed the strength tests, which took a mean 2.47 ± 0.49 min (one limb). Intra-rater reliability was higher for MVIS (0.98_{[0.95–0.99]}) than RFG (ICC = 0.93_{[0.87–0.97]}) for the entire sample. In the non-fallers, ICC was 0.98_{[0.95–1.00]} (SEM = 0.08 N.kg^− 1) for MVIS and 0.88_{[0.75–0.96]} for RFG (SEM = 1.34 N.kg^-1.s^-1). In the fallers, ICC was 0.94_{[0.89–0.98]} (SEM = 0.11 N.kg^− 1) for MVIS and 0.93_{[0.84–0.98]} (SEM = 1.12 N.kg^− 1.s^− 1) for RFG. The BA plot showed that the MVIS and RFG values did not differ across test-sessions, showing that no learning effect occurred (no systematic effect). The mean differences between test-sessions were larger and the LOA smaller in the fallers than in the non-fallers.

Conclusion

Assessment of hip strength in a standing position is feasible, rapid and reliable. We therefore recommend this position for clinical practice. Future studies should investigate the diagnostic value of hip abductor strength in standing to discriminate between fallers and non-fallers, and to determine if change in strength following a falls prevention program reduces the risk of falls.

Working Together and Being Physically Active Are Not Enough to Advise Uniformly and Adequately Low Back Pain Patients: A Cross-Sectional Study

The profession of the health-care providers (HCPs) influences their recommendations to the patients. Conversely, interdisciplinarity seeks to challenge such differences, so that the patient receives one single and consistent therapeutic message. Some studies also suggest associations between HCPs life habits and recommendations. Our hypotheses were (1) that despite interdisciplinary work, the profession remains a predictor of recommendations and (2) that HCPs who are more physically active recommend more activity. Three clinical vignettes were presented to a group of experts of low back pain (LBP) (guidelines), and 20 physicians, 22 physiotherapists, and 23 nurses to assess how they evaluate the symptoms and pathologies of LBP patients and how much work and physical activity they recommend. Physical activity was assessed with accelerometers and questionnaires. Some interprofessional differences remained present within an interdisciplinary team. The nurses were more restrictive and further away from the guidelines. The physicians were the most in line with them. The physiotherapists recommend as much physical activity, but less work activity than the physicians. The level of physical activity of the HCPs is not associated with their recommendations. To ensure a clear and unique message, educational actions may be undertaken to promote the biopsychosocial model and clarify the guidelines.

Prediction of local and metastatic recurrence in solitary fibrous tumor: construction of a risk calculator in a multicenter cohort from the French Sarcoma Group (FSG) database

Background

Solitary fibrous tumors (SFT) are rare unusual ubiquitous soft tissue tumors that are presumed to be of fibroblastic differentiation. At present, the challenge is to establish accurate prognostic factors.

Patients and methods

A total of 214 consecutive patients with SFT diagnosed in 24 participating cancer centers were entered into the European database (www.conticabase.org) to perform univariate and multivariate analysis for overall survival (OS), local recurrence incidence (LRI) and metastatic recurrence incidence (MRI) by taking competing risks into account. A prognostic model was constructed for LRI and MRI. Internal and external validations of the prognostic models were carried out. An individual risk calculator was carried out to quantify the risk of both local and metastatic recurrence.

Results

We restricted our analysis to 162 patients with local disease. Twenty patients (12.3%) were deceased at the time of analysis and the median OS was not reached. The LRI rates at 10 and 20 years were 19.2% and 38.6%, respectively. The MRI rates at 10 and 20 years were 31.4% and 49.8%, respectively. Multivariate analysis retained age and mitotic count tended to significance for predicting OS. The factors influencing LRI were viscera localization, radiotherapy and age. Mitotic count, tumor localization other than limb and age had independent values for MRI. Three prognostic groups for OS were defined based on the number of unfavorable prognostic factors and calculations were carried out to predict the risk of local and metastatic recurrence for individual patients.

Conclusion

LRI and MRI rates increased between 10 and 20 years so relapses were delayed, suggesting that long-term monitoring is useful. This study also shows that different prognostic SFT sub-groups could benefit from different therapeutic strategies and that use of a survival calculator could become standard practice in SFTs to individualize treatment based on the clinical situation.

The cost-saving effect of centralized histological reviews with soft tissue and visceral sarcomas, GIST, and desmoid tumors: The experiences of the pathologists of the French Sarcoma Group

OBJECTIVE

This study examined the types of discordance occurring in the diagnosis of soft tissue and visceral sarcomas, gastrointestinal stromal tumors (GIST), and desmoid tumors, as well as the economic impact of diagnostic discrepancies.

METHODS

We carried out a retrospective, multicenter analysis using prospectively implemented databases performed on a cohort of patients within the French RRePS network in 2010. Diagnoses were deemed to be discordant based on the 2013 World Health Organization (WHO) classification. Predictive factors of discordant diagnoses were explored. A decision tree was used to assess the expected costs of two strategies of disease management: one based on revised diagnoses after centralized histological review (option 1), the other on diagnoses without centralized review (option 2). Both were defined based on the patient and the disease characteristics, according to national or international guidelines. The time horizon was 12 months and the perspective of the French National Health Insurance (NHI) was retained. Costs were expressed in Euros for 2013. Sensitivity analyses were performed using low and high scenarios that included ± 20% estimates for cost.

RESULTS

A total of 2,425 patients were included. Three hundred forty-one patients (14%) had received discordant diagnoses. These discordances were determined to mainly be benign tumors diagnosed as sarcomas (n = 124), or non-sarcoma malignant tumors diagnosed as sarcomas (n = 77). The probability of discordance was higher for a final diagnosis of desmoid tumors when compared to liposarcomas (odds ratio = 5.1; 95%CI [2.6-10.4]). The expected costs per patient for the base-case analysis (low- and high-case scenarios) amounted to €8,791 (€7,033 and €10,549, respectively) for option 1 and €8,904 (€7,057 and €10,750, respectively) for option 2.

CONCLUSIONS

Our findings highlight misdiagnoses of sarcomas, which were found to most often be confused with benign tumors. Centralized histological reviews are likely to provide cost-savings for the French NHI.

MED12 mutations in breast phyllodes tumors: evidence of temporal tumoral heterogeneity and identification of associated critical signaling pathways

Exome sequencing has recently identified highly recurrent MED12 somatic mutations in fibroadenomas (FAs) and phyllodes tumors (PTs). In the present study, based on a large series, we confirmed the presence of MED12 exon 1 and 2 mutations in 49% (41/83) of PTs, 70% (7/10) of FAs and 9.1% (1/11) of fibromatoses. We show that MED12 mutations are associated with benign behavior of phyllodes tumors, as they are detected less frequently in malignant PTs (27.6%) compared to benign (58.3%) and borderline (63.3%) PTs, respectively (p = 0.0036). Phyllodes tumors presented marked temporal heterogeneity of MED12 mutation status, as 50% (3/6) of primary and recurrent phyllodes tumor pairs with MED12 mutation presented different MED12 mutations between the primary and recurrent tumors. There was no correlation between MED12 status and genomic profiles obtained by array-CGH. MED12 mutations are associated with altered expressions of the genes involved in the WNT (PAX3, WNT3A, AXIN2), TGFB (TAGLN, TGFBR2, CTGF) and THRA (RXRA, THRA) signaling pathways.

In conclusion, this study confirmed that MED12 plays a central oncogenic role in breast fibroepithelial tumorigenesis and identified a limited number of altered signaling pathways that maybe associated with MED12 mutations. MED12 exon 1 and 2 mutation status and some of the altered genes identified in this study could constitute useful diagnostic or prognostic markers, and form the basis for novel therapeutic strategies for PTs.

Hip muscle and hand-grip strength to differentiate between older fallers and non-fallers: a cross-sectional validity study

Background

Hip muscle weakness in older people seems to be an influencing factor of falls. Currently, it is unclear which muscles out of the hip muscle group play an important role in older people. A validating process in the measurement regarding muscle strength related to falls is necessary before answering that question.

Objective

Firstly, we aimed to investigate which hip muscle group strength shows an acceptable level of distinction between older adult fallers and non-fallers compared to a predefined external criterion regarding falling. Secondly, we aimed to compare the same outcomes and questions for hand-grip strength in relation to the same external criterion.

Design

This study was a cross-sectional validity study.

Methods

The maximum voluntary isometric strength (MVIS) and the rate of force generation of hip abductors (ABD), adductors, internal and external rotators, extensors, and flexors were measured with a dynamometer fixed to a custom-made frame as well as hand-grip strength with a Martin Vigorimeter in 60 older people aged over 65 years (38 females and 22 males).

Results

The area under the curve (AUC) and the results of the mean decrease in Gini index assessed by random forest approach show that of all the assessed parameters, hip ABD MVIS showed the highest discriminative value regarding the chosen external criterion in older people (AUC ABD MVIS 0.825, 95% confidence interval: 0.712-0.938).

Conclusion

Results indicate that ABD MVIS is a useful measure to distinguish between older adult fallers and non-fallers regarding the chosen external criterion.

Presentation and outcome of frequent and rare sarcoma histologic subtypes: A study of 10,262 patients with localized visceral/soft tissue sarcoma managed in reference centers

BACKGROUND

The objective of this study was to describe characteristics at diagnosis and outcomes of adults with soft tissue sarcoma.

METHODS

The authors conducted a retrospective multicenter study of 12,262 patients who were treated between January 1980 and 31 December 2013 in French Sarcoma Group centers and enrolled in the "Conticabase." Diagnoses were systematically reviewed by expert pathologists, and entities were classified according to the 2013 World Health Organization classification. Diagnostic characteristics, treatments, and outcomes are described for the entire cohort, for the subgroup of patients with translocation-related sarcomas, and for 9 different histologic subtypes.

RESULTS

The results stressed the magnitude of heterogeneity among adult sarcomas. For example, compared with other sarcomas, translocation-related sarcomas (2143 tumors; 20.8%) were associated with a younger age at presentation (40.6 vs 60.0 years; P < .0001), a low rate of predisposing conditions (0.01% vs 22.3%; P < .0001), a higher rate of lymph node involvement (4.7% vs 1.3%; P < .0001), and a higher rate of synchronous metastasis (11.9% vs 6.7%; P < .001); and complete (R0) resection (41.6% vs 31.9%; P < .0001), receipt of (neo)adjuvant radiation therapy (62.6% vs 42.2%; P < .0001), and receipt of (neo)adjuvant chemotherapy (36.6% vs 22.3%; P < .0001) were significantly more frequent. Overall, translocation-related sarcomas were associated with a lower rate of local relapse (18.1% vs 26.0%; P < .0001) but a higher rate of metastatic relapse (42.0% vs 30.7%; P < .0001).

CONCLUSIONS

Collaborative efforts are urgently needed to better assess the natural history and management options for every histologic subtype of sarcoma. Cancer 2018;124:1179-87. © 2017 American Cancer Society.

Determinants of gait stability while walking on a treadmill: A machine learning approach

Dynamic balance in human locomotion can be assessed through the local dynamic stability (LDS) method. Whereas gait LDS has been used successfully in many settings and applications, little is known about its sensitivity to individual characteristics of healthy adults. Therefore, we reanalyzed a large dataset of accelerometric data measured for 100 healthy adults from 20 to 70 years of age performing 10 min treadmill walking. We sought to assess the extent to which the variations of age, body mass and height, sex, and preferred walking speed (PWS) could influence gait LDS. The random forest (RF) and multiple adaptive regression splines (MARS) algorithms were selected for their good bias-variance tradeoff and their capabilities to handle nonlinear associations. First, through variable importance measure (VIM), we used RF to evaluate which individual characteristics had the highest influence on gait LDS. Second, we used MARS to detect potential interactions among individual characteristics that may influence LDS. The VIM and MARS results indicated that PWS and age correlated with LDS, whereas no associations were found for sex, body height, and body mass. Further, the MARS model detected an age by PWS interaction: on one hand, at high PWS, gait stability is constant across age while, on the other hand, at low PWS, gait instability increases substantially with age. We conclude that it is advisable to consider the participants' age as well as their PWS to avoid potential biases in evaluating dynamic balance through LDS.

Germline CDKN2A/P16INK4A mutations contribute to genetic determinism of sarcoma

BACKGROUND

Sarcomas are rare mesenchymal malignancies whose pathogenesis is poorly understood; both environmental and genetic risk factors could contribute to their aetiology.

METHODS AND RESULTS

We performed whole-exome sequencing (WES) in a familial aggregation of three individuals affected with soft-tissue sarcoma (STS) without TP53 mutation (Li-Fraumeni-like, LFL) and found a shared pathogenic mutation in CDKN2A tumour suppressor gene. We searched for individuals with sarcoma among 474 melanoma-prone families with a CDKN2A-/+ genotype and for CDKN2A mutations in 190 TP53-negative LFL families where the index case was a sarcoma. Including the initial family, eight independent sarcoma cases carried a germline mutation in the CDKN2A/p16INK4A gene. In five out of seven formalin-fixed paraffin-embedded sarcomas, heterozygosity was lost at germline CDKN2A mutations sites demonstrating complete loss of function. As sarcomas are rare in CDKN2A/p16INK4A carriers, we searched in constitutional WES of nine carriers for potential modifying rare variants and identified three in platelet-derived growth factor receptor (PDGFRA) gene. Molecular modelling showed that two never-described variants could impact the PDGFRA extracellular domain structure.

CONCLUSION

Germline mutations in CDKN2A/P16INK4A, a gene known to predispose to hereditary melanoma, pancreatic cancer and tobacco-related cancers, account also for a subset of hereditary sarcoma. In addition, we identified PDGFRA as a candidate modifier gene.