The Multifaceted Actions of CD73 During Development and Suppressive Actions of Regulatory T Cells

Adenosine (Ado) has been shown to have immunosuppressive effects in a variety of diseases. It can either be released directly into the extracellular environment by cells, or it can be produced by degradation of ATP within the extracellular spaces. This extracellular pathway is facilitated by the concerted actions of the ectoenzymes CD39 and CD73. In a first step CD39 dephosphorylates ATP to ADP and AMP, respectively, and in a second step CD73 converts AMP to Ado. Thus, activity of CD73 on the cell surface of cells is the rate limiting step in the generation of extracellular Ado. Among T cells, CD73 is most abundantly expressed by regulatory T cells (Tregs) and is even upregulated after their activation. Functionally, the generation of Ado by CD73+ Tregs has been shown to play a role in immune suppression of dendritic cells, monocytes and T cells, and the defined expression of CD73 by Tregs in immunosuppressive environments, such as tumors, made CD73 a novel checkpoint inhibitor. Therefore, therapeutical intervention by anti-CD73 antibodies or by chemical inhibitors of the enzymatic function is currently under investigation in some preclinical animal models. In the following we summarize the expression pattern and the possible functions of CD73 in T cells and Tregs, and exemplify novel ways to manipulate CD73 functions in Tregs to stimulate anti-tumor immunity.

Evaluation of radio-immunotherapy sequence on immunological responses and clinical outcomes in patients with melanoma brain metastases (ELEKTRA)

In patients with melanoma brain metastases (MBM), a combination of radiotherapy (RT) with immune checkpoint inhibitors (ICI) is routinely used. However, the best sequence of radio-immunotherapy (RIT) remains unclear. In an exploratory phase 2 trial, MBM patients received RT (stereotactic or whole-brain radiotherapy depending on the number of MBM) combined with ipilimumab (ipi) ± nivolumab (nivo) in different sequencing (Rad-ICI or ICI-Rad). Comparators arms included patients treated with ipi-free systemic treatment or without RT (in MBM-free patients). The primary endpoints were radiological and immunological responses in the peripheral blood. Secondary endpoints were progression-free survival (PFS) and overall survival (OS). Of 106 screened, 92 patients were included in the study. Multivariate analysis revealed an advantage for patients starting with RT (Rad-ICI) for overall response rate (RR: p = .007; HR: 7.88 (95%CI: 1.76–35.27)) and disease control rate (DCR: p = .036; HR: 6.26 (95%CI: 1.13–34.71)) with a trend for a better PFS (p = .162; HR: 1.64 (95%CI: 0.8–3.3)). After RT plus two cycles of ipi-based ICI in both RIT sequences, increased frequencies of activated CD4, CD8 T cells and an increase in melanoma-specific T cell responses were observed in the peripheral blood. Lasso regression analysis revealed a significant clinical benefit for patients treated with Rad-ICI sequence and immunological features, including high frequencies of memory T cells and activated CD8 T cells in the blood. This study supports increasing evidence that sequencing RT followed by ICI treatment may have better effects on the immunological responses and clinical outcomes in MBM patients.

[Plantar melanoma: A wolf in sheep's clothing]

BACKGROUND AND FINDINGS

 Amelanotic melanoma (AM) is a subtype of melanoma characterized by a diminished or lacking melanin synthesis. AM, especially ulcerated variants of the plantar region (AMP), are often clinically misdiagnosed, leading to a delay in treatment initiation.

THERAPY AND FURTHER DEVELOPMENT

 We present a case series of 4 AMP and give a detailed overview about clinical features and the subsequent medical history of this severe disease.

CONCLUSIONS

 AMP shows a variety of clinical presentations and particularly elderly patients with many accompanying medical conditions are in danger of incorrect clinical diagnoses. Therefore, we recommend to biopsy any amelanotic plantar ulcer or tumor that does not respond to treatment within 6 weeks to rule out AM.

Does sex matter? Analysis of sex-related differences in the diagnostic performance of a market-approved convolutional neural network for skin cancer detection

BACKGROUND

Advances in biomedical artificial intelligence may introduce or perpetuate sex and gender discriminations. Convolutional neural networks (CNN) have proven a dermatologist-level performance in image classification tasks but have not been assessed for sex and gender biases that may affect training data and diagnostic performance. In this study, we investigated sex-related imbalances in training data and diagnostic performance of a market-approved CNN for skin cancer classification (Moleanalyzer Pro®, Fotofinder Systems GmbH, Bad Birnbach, Germany).

METHODS

We screened open-access dermoscopic image repositories widely used for CNN training for distribution of sex. Moreover, the sex-related diagnostic performance of the market-approved CNN was tested in 1549 dermoscopic images stratified by sex (female n = 773; male n = 776).

RESULTS

Most open-access repositories showed a marked under-representation of images originating from female (40%) versus male (60%) patients. Despite these imbalances and well-known sex-related differences in skin anatomy or skin-directed behaviour, the tested CNN achieved a comparable sensitivity of 87.0% [80.9%-91.3%] versus 87.1% [81.1%-91.4%], specificity of 98.7% [97.4%-99.3%] versus 96.9% [95.2%-98.0%] and ROC-AUC of 0.984 [0.975-0.993] versus 0.979 [0.969-0.988] in dermoscopic images of female versus male origin, respectively. In the sample at hand, sex-related differences in ROC-AUCs were not statistically significant in the per-image analysis nor in an additional per-individual analysis (p ≥ 0.59).

CONCLUSION

Design and training of artificial intelligence algorithms for medical applications should generally acknowledge sex and gender dimensions. Despite sex-related imbalances in open-access training data, the diagnostic performance of the tested CNN showed no sex-related bias in the classification of skin lesions.

[Immunohistochemical analysis of a hypoxia-associated signature in melanomas with positive and negative sentinel lymph nodes : Hypoxia-associated signature of primary cutaneous melanomas]

Metabolic reprogramming mediated by hypoxia-inducible factors and its downstream targets plays a crucial role in many human malignancies. Excessive proliferation of tumor cells under hypoxic conditions leads to metabolic reprogramming and altered gene expression enabling tumors to adapt to their hypoxic environment. Here we analyzed the metabolic signatures of primary cutaneous melanomas with positive and negative sentinel node status in order to evaluate potential differences in their metabolic signature. We found a positive correlation of the expression of glucose transporter 1 (GLUT-1) with tumor thickness and ulceration in all melanomas with subgroup analyses as well as in the subgroup with a negative sentinel node. Furthermore, the expression of vascular endothelial growth factor (VEGF) was positively correlated with the presence of ulceration in melanomas with positive sentinel node.

Mikrovaskuläre Pathologien bei Patienten mit Psoriasis vulgaris mittels Nagelfalzkapillarmikroskopie identifiziert: Ergebnisse einer prospektiven kontrollierten Studie

Hintergrund: Die Psoriasis gilt als unabhängiger kardiovaskulärer Risikofaktor und Treiber einer Atherogenese. Mikrovaskuläre Veränderungen in psoriatischen Plaques sind gut beschrieben, wohingegen Veränderungen außerhalb betroffener Hautareale kaum untersucht wurden. In dieser Studie wurden Nagelfalzkapillaren von Psoriasispatienten in nicht betroffener Haut systematisch untersucht. Patienten und Methodik: Prospektive Studie mit Untersuchung von Nagelfalzkapillaren bei Psoriasispatienten im Vergleich zu gesunden Kontrollen mittels digitaler Videokapillarmikroskopie. Es wurden 21 kapillarmikroskopische Parameter bewertet und die Ergebnisse mit Charakteristika der Patienten und der Psoriasiserkrankung, mit Laborparametern und Messungen der Intima-Media-Dicke der Arteria carotis communis korreliert. Ergebnisse: Die 77 Psoriasispatienten (24 mit zusätzlicher Psoriasisarthritis) und 71 Kontrollen zeigten sich hinsichtlich demographischer Merkmale und relevanter Einflussfaktoren für eine Mikroangiopathie ausbalanciert. Im Vergleich zur Kontrollgruppe zeigten Psoriasispatienten eine signifikante Minderung der kapillaren Dichte, häufigere Kapillarerweiterung mit mehr Verzweigungen, Torquierungen und kapillaren Unregelmäßigkeiten. Zusätzlich zeigten Psoriasispatienten signifikant höhere inflammatorische Serummarker und eine gesteigerte Intima-Media-Dicke. In unserem Kollektiv bestand kein Zusammenhang zwischen Krankheitsdauer oder Schweregrad der Psoriasis und spezifischen Kapillarveränderungen. Schlussfolgerungen: Die Nagelfalzkapillaren der untersuchten Psoriasispatienten zeigten ausgeprägte mikrovaskuläre Veränderungen, welche mit erhöhten Markern einer systemischen Entzündung und Frühzeichen einer Atherosklerose korrelierten. Weitere Studien sind erforderlich, um die Rolle der digitalen Videokapillarmikroskopie in der Bewertung des kardiovaskulären Risikos von Psoriasispatienten zu untersuchen.

A Case of Extensive Grover’s Disease in a Patient with a History of Multiple Non-Melanoma Skin Cancers

We report on a 69-year-old man who presented with itching and erythematous papules on his torso and extremities, which were resistant to topical therapy with antibiotics and steroids. Physical examination revealed multiple erythematous papules on his back, neckline, and lower extremities. The lesions had appeared 4 years earlier and usually worsened with heat or extensive sweating. Histopathology of previous skin biopsies had shown multiple cutaneous squamous cell carcinomas or was non-conclusive. Thus, a re-biopsy was performed, revealing acanthosis and focal acantholytic dyskeratosis. These clinical and anamnestic findings lead to the diagnosis of extensive Grover’s disease (GD). Oral therapy with isotretinoin 30-mg QD led to the regression of the skin lesions. Topical adapalene, as well as topical corticosteroids, were later prescribed for maintenance therapy.

Improvement in Quality of Life and Pain in Patients With Hidradenitis Suppurativa After Wide Local Excision: A Prospective Study

BACKGROUND

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease that affects patients' quality of life (QoL).

OBJECTIVE

To investigate changes in QoL in patients with HS after wide local excision (WLE) and to examine the level of pain, rate of postoperative complications, recurrences, and the time to complete wound closure.

METHODS

Fifty-five patients were enrolled in this prospective study. All patients underwent WLE of HS, followed by secondary wound healing. Dermatologic Life Quality Questionnaire, pain, and wound size were measured 1 day, 3 weeks, 3 months, and 6 months after surgery.

RESULTS

Dermatologic Life Quality Questionnaire and pain scores (mean ± SD) improved significantly (both p < .001) from 14.5 ± 7.3 and 3.7 ± 2.8 at baseline to 5.8 ± 6.9 and 0.8 ± 1.7, 6 months postoperatively, respectively. Wounds were closed completely by secondary intention after 4.4 ± 2.8 months. Sixteen patients (29.1%) experienced postoperative complications, local recurrences in the treated sites were observed in 11 patients (20%), and new lesions in untreated sites were observed in 5 cases (9.1%).

CONCLUSION

Wide local excision significantly improves patients' QoL and pain, and, given its low rate of recurrence and complications, should be considered as a first-line therapy, especially in patients with higher Hurley stages.

Monitoring patients at risk for melanoma: May convolutional neural networks replace the strategy of sequential digital dermoscopy?

BACKGROUND

Sequential digital dermoscopy (SDD) is applied for early melanoma detection by uncovering dynamic changes of monitored lesions. Convolutional neural networks (CNN) are capable of high diagnostic accuracies similar to trained dermatologists.

OBJECTIVES

To investigate the capability of CNN to correctly classify melanomas originally diagnosed by mere dynamic changes during SDD.

METHODS

A retrospective cross-sectional study using image quartets of 59 high-risk patients each containing one melanoma diagnosed by dynamic changes during SDD and three nevi (236 lesions). Two validated CNN classified quartets at baseline or after SDD follow-up at the time of melanoma diagnosis. Moreover, baseline quartets were rated by 26 dermatologists. The main outcome was the number of quartets with correct classifications.

RESULTS

CNN-1 correctly classified 9 (15.3%) and CNN-2 8 (13.6%) of 59 baseline quartets. In baseline images, CNN-1 attained a sensitivity of 25.4% (16.1%-37.8%) and specificity of 92.7% (87.8%-95.7%), whereas CNN-2 of 28.8% (18.8%-41.4%) and 75.7% (68.9%-81.4%). Expectedly, after SDD follow-up CNN more readily detected melanomas resulting in improved sensitivities (CNN-1: 44.1% [32.2%-56.7%]; CNN-2: 49.2% [36.8%-61.6%]). Dermatologists were told that each baseline quartet contained one melanoma, and on average, correctly classified 24 (22-27) of 59 quartets. Correspondingly, accepting a baseline quartet to be appropriately classified whenever the highest malignancy score was assigned to the melanoma within, CNN-1 and CNN-2 correctly classified 28 (47.5%) and 22 (37.3%) of 59 quartets, respectively.

CONCLUSIONS

The tested CNN could not replace the strategy of SDD. There is a need for CNN capable of integrating information on dynamic changes into analyses.

Nailfold videocapillaroscopy identifies microvascular pathologies in psoriasis vulgaris: Results of a prospective controlled study

BACKGROUND

Psoriasis is considered an independent cardiovascular risk factor, evidentially driving atherosclerosis. However, little is known about changes in the microvasculature of non-lesional skin in psoriasis patients. This study systematically examined capillary pathologies in psoriasis patients by digital video nailfold capillaroscopy.

PATIENTS AND METHODS

Prospective study comparing nailfold capillaries of psoriasis patients with those of healthy controls. Nailfold capillaries were evaluated for 21 parameters and results were correlated with characteristics of patients and psoriatic disease, laboratory parameters, and measurements of carotid intima-media thickness.

RESULTS

77 psoriasis patients (24 patients with additional psoriatic arthritis) and 71 controls were well-matched for demographic features and for relevant confounding factors causing microangiopathy. In comparison with controls, psoriasis patients showed a significant loss of capillaries, capillary expansion with increased ramifications and tortuosity and capillary irregularities. Moreover, in psoriasis patients we found significantly elevated serum markers of inflammation and significantly increased intima-media-thickness measurements. We found no effect of disease duration nor disease activity on capillary changes.

CONCLUSIONS

Nailfold capillaries of psoriasis patients showed marked microvascular abnormalities accompanied by increased markers of systemic inflammation and atherosclerosis. Prospective cohort studies are needed to assess the role of nailfold capillaroscopy for predicting the cardiovascular risk of psoriasis patients.

Formation of keto-type ceramides in palmoplantar keratoderma based on biallelic KDSR mutations in patients

Functional skin barrier requires sphingolipid homeostasis. 3-ketodihydrosphingosine reductase or KDSR is a key enzyme of sphingolipid anabolism catalyzing the reduction of 3-ketodihydrosphingosine to sphinganine. Biallelic mutations in the KDSR gene may cause erythrokeratoderma variabilis et progressive-4, later specified as PERIOPTER syndrome, emphasizing a characteristic periorifical and ptychotropic erythrokeratoderma. We report another patient with compound heterozygous mutations in KDSR, born with generalized harlequin ichthyosis, which progressed into palmoplantar keratoderma. To determine whether patient-associated KDSR mutations lead to KDSR substrate accumulation and/or unrecognized sphingolipid downstream products in stratum corneum we analyzed lipids of this and previously published patients with non-identical biallelic mutations in KDSR. In stratum corneum of both patients we identified hitherto unobserved skin ceramides with an unusual keto-type sphingoid base in lesional and non-lesional areas, which accounted for up to 10% of the measured ceramide species. Furthermore, an overall shorter mean chain length of free and bound sphingoid bases was observed-shorter mean chain length of free sphingoid bases was also observed in lesional psoriasis vulgaris SC, but not generally in lesional atopic dermatitis SC. Formation of keto-type ceramides is probably due to a bottle neck in metabolic flux through KDSR and a bypass by ceramide synthases, which highlights the importance of tight intermediate regulation during sphingolipid anabolism and reveals substrate deprivation as potential therapy.

Detailed Long-term Dynamics of Neutrophil-to-Lymphocyte Ratio under Biologic Treatment Reveals Differential Effects of Tumour Necrosis Factor-alpha and Interleukin 12/23 Antagonists

Psoriasis is thought to be associated with a reduced life expectancy through systemic inflammation. A comparative, retrospective analysis of neutrophil-to-lympho-cyte ratio, a biomarker of systemic inflammation and cardiovascular risk, under 196 treatments with tumour necrosis factor-α and interleukin-12/23 antagonists was performed. Neutrophil-to-lympho-cyte ratio decreased significantly within 3 months of initiation of treatment and remained stable at reduced levels for at least 33 months. Dynamics were more pronounced and neutrophil-to-lympho-cyte ratio under treatment was lower in patients treated with tumour necrosis factor-α compared with interleukin-12/23 antagonists (geometric mean (95% confidence interval): 2.03 (1.9, 2.1) vs 2.63 (2.2, 3.2), respectively, p = 0.014). tumour necrosis factor-α antagonist treatment and baseline neutrophil-to-lympho-cyte ratio were independent predictors of a median low cardiovascular risk neutrophil-to-lympho-cyte ratio (< 2.15) during treatment (odds ratio (95% confidence interval): 0.53 (0.4-0.8) and 4.68 (1.0-19.1), p = 0.001 and p = 0.032, respectively). These results demonstrate a rapid and sustained reduction in biomarkers of systemic inflammation under biologic treatment. Furthermore, these data suggest class-specific effects on systemic inflammation, which may be relevant for the prevention of psoriasis co-morbidity by systemic treatment.

Auswirkungen des „dunklen Rand‐Artefakts“ in dermatoskopischen Bildern auf die diagnostische Leistungsfähigkeit eines deep learning neuronalen Netzwerkes mit Marktzulassung

HINTERGRUND UND ZIELE

Systeme künstlicher Intelligenz (durch "deep learning" faltende neuronale Netzwerke; engl. convolutional neural networks, CNN) erreichen inzwischen bei der Klassifikation von Hautläsionen vergleichbar gute Ergebnisse wie Dermatologen. Allerdings müssen die Limitationen solcher Systeme vor flächendeckendem klinischem Einsatz bekannt sein. Daher haben wir den Einfluss des "dunklen Rand-Artefakts" (engl. dark corner artefact; DCA) in dermatoskopischen Bildern auf die diagnostische Leistung eines CNN mit Marktzulassung zur Klassifikation von Hautläsionen untersucht.

PATIENTEN UND METHODEN

Ein Datensatz aus 233 Bildern von Hautläsionen (60 maligne und 173 benigne) ohne DCA (Kontrolle) wurde digital so modifiziert, dass kleine, mittlere oder große DCA zu sehen waren. Alle 932 Bilder wurden dann mittels CNN mit Marktzulassung (Moleanalyzer-Pro^® , FotoFinder Systems) auf Malignitätsscores hin analysiert. Das Spektrum reichte von 0-1; ein Score von > 0,5 wurde als maligne klassifiziert.

ERGEBNISSE

In der Kontrollserie ohne DCA erreichte das CNN eine Sensitivität von 90,0 % (79,9 %-95,3 %), eine Spezifität von 96,5 % (92,6 %-98,4 %) sowie eine Fläche unter der Kurve (AUC, area under the curve) der "receiver operating characteristic" (ROC) von 0,961 (0,932-0,989). In den Datensätzen mit kleinen beziehungsweise mittleren DCA war die diagnostische Leistung vergleichbar. In den Bildersätzen mit großen DCA wurden allerdings signifikant höhere Malignitätsscores erzielt. Dies führte zu einer signifikant verminderten Spezifität (87,9 % [82,2 %-91,9 %], P < 0,001) sowie einer nicht signifikant erhöhten Sensitivität (96,7 % [88,6 %-99,1 %]). Die ROC-AUC blieb mit 0,962 (0,935-0,989) unverändert.

SCHLUSSFOLGERUNGEN

Die Klassifizierung mittels des CNN war bei dermatoskopischen Bildern mit kleinen oder mittleren DCA nicht beeinträchtigt, das System zeigte jedoch Schwächen bei großen DCA. Wenn Ärzte solche Bilder zur Klassifikation mittels CNN einreichen, sollten sie sich dieser Grenzen der Technologie bewusst sein.

Collective human intelligence outperforms artificial intelligence in a skin lesion classification task

BACKGROUND AND OBJECTIVES

Convolutional neural networks (CNN) enable accurate diagnosis of medical images and perform on or above the level of individual physicians. Recently, collective human intelligence (CoHI) was shown to exceed the diagnostic accuracy of individuals. Thus, diagnostic performance of CoHI (120 dermatologists) versus individual dermatologists versus two state-of-the-art CNN was investigated.

PATIENTS AND METHODS

Cross-sectional reader study with presentation of 30 clinical cases to 120 dermatologists. Six diagnoses were offered and votes collected via remote voting devices (quizzbox®, Quizzbox Solutions GmbH, Stuttgart, Germany). Dermatoscopic images were classified by a binary and multiclass CNN (FotoFinder Systems GmbH, Bad Birnbach, Germany). Three sets of diagnostic classifications were scored against ground truth: (1) CoHI, (2) individual dermatologists, and (3) CNN.

RESULTS

CoHI attained a significantly higher accuracy [95 % confidence interval] (80.0 % [62.7 %-90.5 %]) than individual dermatologists (75.7 % [73.8 %-77.5 %]) and CNN (70.0 % [52.1 %-83.3 %]; all P < 0.001) in binary classifications. Moreover, CoHI achieved a higher sensitivity (82.4 % [59.0 %-93.8 %]) and specificity (76.9 % [49.7 %-91.8 %]) than individual dermatologists (sensitivity 77.8 % [75.3 %-80.2 %], specificity 73.0 % [70.6 %-75.4 %]) and CNN (sensitivity 70.6 % [46.9 %-86.7 %], specificity 69.2 % [42.4 %-87.3 %]). The diagnostic accuracy of CoHI was superior to that of individual dermatologists (P < 0.001) in multiclass evaluation, with the accuracy of the latter comparable to multiclass CNN.

CONCLUSIONS

Our analysis revealed that the majority vote of an interconnected group of dermatologists (CoHI) outperformed individuals and CNN in a demanding skin lesion classification task.

[Successful treatment of chronic prurigo with dupilumab]

Chronische Prurigo ist durch anhaltenden Pruritus, teils einhergehend mit sekundären Kratzläsionen, gekennzeichnet. Die Abklärung der Genese ist von besonderem Stellenwert, wobei eine atopische Diathese häufig einen ätiologischen Faktor darstellt. Wir präsentieren einen Patienten mit chronischem Pruritus multifaktorieller Genese (atopische Diathese, chronische Niereninsuffizienz, Diabetes mellitus, Polyneuropathie). Nach multiplen erfolglosen Vortherapien behandelten wir den Patienten mit Dupilumab, worunter sich ein sehr positiver Erkrankungsverlauf mit deutlicher Besserung der Lebensqualität zeigte.

Complete Metabolic Response in FDG-PET-CT Scan before Discontinuation of Immune Checkpoint Inhibitors Correlates with Long Progression-Free Survival

Simple Summary

Immunotherapy is the standard of care in patients harboring metastasized melanoma. However, once further tumor growth is stopped it remains unclear when immunotherapy can be safely ceased. This clinical question is increasingly raised especially in patients with a strong desire to discontinue therapy or in patients who are forced to pause treatment due to severe immune-related side effects. With our study we aim to provide data which may be helpful for clinicians and patients when treatment discontinuation is considered. Further prospective, multicenter studies are needed to further address this important clinical issue.

Abstract

Checkpoint inhibitors have revolutionized the treatment of patients with metastasized melanoma. However, it remains unclear when to stop treatment. We retrospectively analyzed 45 patients (median age 64 years; 58% male) with metastasized melanoma from 3 cancer centers that received checkpoint inhibitors and discontinued therapy due to either immune-related adverse events or patient decision after an (¹⁸F)2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) combined with a low-dose CT scan (FDG-PET-CT) scan without signs for disease progression. After a median of 21 (range 1–42) months of immunotherapy an FDG-PET-CT scan was performed to evaluate disease activity. In these, 32 patients (71%) showed a complete metabolic response (CMR) and 13 were classified as non-CMR. After a median follow-up of 34 (range 1–70) months, 3/32 (9%) of CMR patients and 6/13 (46%) of non-CMR patients had progressed (p = 0.007). Progression-free survival (PFS), as estimated from the date of last drug administration, was significantly longer among CMR patients than non-CMR (log-rank: p = 0.001; hazard ratio: 0.127; 95% CI: 0.032–0.511). Two-year PFS was 94% among CMR patients and 62% among non-CMR patients. Univariable Cox regression showed that metabolic response was the only parameter which predicted PFS (p = 0.004). Multivariate analysis revealed that metabolic response predicted disease progression (p = 0.008). In conclusion, our findings suggest that patients with CMR in an FDG-PET-CT scan may have a favorable outcome even if checkpoint inhibition is discontinued.

Soluble immune checkpoints and T-cell subsets in blood as biomarkers for resistance to immunotherapy in melanoma patients

Different mechanisms lead to immune checkpoint inhibitor (ICI) resistance. Identifying clinically useful biomarkers might improve drug selection and patients’ therapy. We analyzed the soluble immune checkpoints sPD1, sPDL1, sLAG3, and sTIM3 using ELISA and their expression on circulating T cells using FACS in pre- and on-treatment blood samples of ICI treated melanoma patients. In addition, pre-treatment melanoma metastases were stained for TIM3 and LAG3 expression by IHC. Results were correlated with treatment response and progression-free survival (PFS). Resistance to anti-PD1 treatment (n = 48) was associated with high pre-treatment serum levels of sLAG3 (DCR: p = .009; PFS: p = .018; ROC cutoff >148 pg/ml) but not sPD1, sPDL1 or sTIM3. In contrast, resistance to ipilimumab plus nivolumab (n = 42) was associated with high levels of sPD1 (DCR: p = .019, PFS: p = .046; ROC cutoff >167 pg/ml) but not sPDL1, sLAG3 or sTIM3. Both treatment regimens shared a profound increase of sPD1 serum levels with treatment (p < .0001). FACS analysis revealed reduced frequencies of CD3+ CD8+ PD1 + T cells (p = .028) in anti-PD1-resistant patients, whereas increased frequencies of CD3+ CD4+ LAG3 + T cells characterized patients resistant to ipilimumab plus nivolumab (p = .033). Unlike anti-PD1 monotherapy, combination blockade significantly increased proliferating T cells (CD3+ CD8+ Ki67 + T cells; p < .0001) and eosinophils (p = .001). In melanoma metastases, an increased infiltration with TIM3+ or LAG3 + T cells in the tumor microenvironment correlated with a shorter PFS under anti-PD1 treatment (TIM3: p = .019, LAG3: p = .07). Different soluble immune checkpoints characterized checkpoint inhibitor-resistant melanoma. Measuring these serum markers may have the potential to be used in clinical routine.

Dark corner artefact and diagnostic performance of a market-approved neural network for skin cancer classification

BACKGROUND AND OBJECTIVES

Convolutional neural networks (CNN) have proven dermatologist-level performance in skin lesion classification. Prior to a broader clinical application, an assessment of limitations is crucial. Therefore, the influence of a dark tubular periphery in dermatoscopic images (also called dark corner artefact [DCA]) on the diagnostic performance of a market-approved CNN for skin lesion classification was investigated.

PATIENTS AND METHODS

A prospective image set of 233 skin lesions (60 malignant, 173 benign) without DCA (control-set) was modified to show small, medium or large DCA. All 932 images were analyzed by a market-approved CNN (Moleanalyzer-Pro^® , FotoFinder Systems), providing malignancy scores (range 0-1) with the cut-off > 0.5 indicating malignancy.

RESULTS

In the control-set the CNN achieved a sensitivity of 90.0 % (79.9 % - 95.3 %), a specificity of 96.5 % (92.6 % - 98.4 %), and an area under the curve (AUC) of receiver operating characteristics (ROC) of 0.961 (0.932 - 0.989). Comparable diagnostic performance was observed in the DCAsmall-set and DCAmedium-set. Conversely, in the DCAlarge-set significantly increased malignancy scores triggered a significantly decreased specificity (87.9 % [82.2 % - 91.9 %], P < 0.001), non-significantly increased sensitivity (96.7 % [88.6 % - 99.1 %]) and unchanged ROC-AUC of 0.962 (0.935 - 0.989).

CONCLUSIONS

Convolutional neural network classification was robust in images with small and medium DCA, but impaired in images with large DCA. Physicians should be aware of this limitation when submitting images to CNN classification.