Genome sequencing and analysis of the Tasmanian devil and its transmissible cancer.

The Tasmanian devil (Sarcophilus harrisii), the largest marsupial carnivore, is endangered due to a transmissible facial cancer spread by direct transfer of living cancer cells through biting. Here we describe the sequencing, assembly, and annotation of the Tasmanian devil genome and whole-genome sequences for two geographically distant subclones of the cancer. Genomic analysis suggests that the cancer first arose from a female Tasmanian devil and that the clone has subsequently genetically diverged during its spread across Tasmania. The devil cancer genome contains more than 17,000 somatic base substitution mutations and bears the imprint of a distinct mutational process. Genotyping of somatic mutations in 104 geographically and temporally distributed Tasmanian devil tumors reveals the pattern of evolution and spread of this parasitic clonal lineage, with evidence of a selective sweep in one geographical area and persistence of parallel lineages in other populations.

Evolution and lineage dynamics of a transmissible cancer in Tasmanian devils.

Devil facial tumour 1 (DFT1) is a transmissible cancer clone endangering the Tasmanian devil. The expansion of DFT1 across Tasmania has been documented, but little is known of its evolutionary history. We analysed genomes of 648 DFT1 tumours collected throughout the disease range between 2003 and 2018. DFT1 diverged early into five clades, three spreading widely and two failing to persist. One clade has replaced others at several sites, and rates of DFT1 coinfection are high. DFT1 gradually accumulates copy number variants (CNVs), and its telomere lengths are short but constant. Recurrent CNVs reveal genes under positive selection, sites of genome instability, and repeated loss of a small derived chromosome. Cultured DFT1 cell lines have increased CNV frequency and undergo highly reproducible convergent evolution. Overall, DFT1 is a remarkably stable lineage whose genome illustrates how cancer cells adapt to diverse environments and persist in a parasitic niche.

Transmissible cancer influences immune gene expression in an endangered marsupial, the Tasmanian devil (Sarcophilus harrisii).

Understanding the effects of wildlife diseases on populations requires insight into local environmental conditions, host defence mechanisms, host life-history trade-offs, pathogen population dynamics, and their interactions. The survival of Tasmanian devils (Sarcophilus harrisii) is challenged by a novel, fitness limiting pathogen, Tasmanian devil facial tumour disease (DFTD), a clonally transmissible, contagious cancer. In order to understand the devils' capacity to respond to DFTD, it is crucial to gain information on factors influencing the devils' immune system. By using RT-qPCR, we investigated how DFTD infection in association with intrinsic (sex and age) and environmental (season) factors influences the expression of 10 immune genes in Tasmanian devil blood. Our study showed that the expression of immune genes (both innate and adaptive) differed across seasons, a pattern that was altered when infected with DFTD. The expression of immunogbulins IgE and IgM:IgG showed downregulation in colder months in DFTD infected animals. We also observed strong positive association between the expression of an innate immune gene, CD16, and DFTD infection. Our results demonstrate that sampling across seasons, age groups and environmental conditions are beneficial when deciphering the complex ecoevolutionary interactions of not only conventional host-parasite systems, but also of host and diseases with high mortality rates, such as transmissible cancers.

Transmissible cancer and longitudinal telomere dynamics in Tasmanian devils (Sarcophilus harrisii).

A plethora of intrinsic and environmental factors have been shown to influence the length of telomeres, the protector of chromosome ends. Despite the growing interest in infection-telomere interactions, there is very limited knowledge on how transmissible cancers influence telomere maintenance. An emblematic example of transmissible cancer occurs in the Tasmanian devil (Sarcophilus harrisii), whose populations have been dramatically reduced by infectious cancer cells. To investigate associations between telomere dynamics and the transmissible cancer, we used longitudinal data from a Tasmanian devil population that has been exposed to the disease for over 15 years. We detected substantial temporal variation in individual telomere length (TL), and a positive significant association between TL and age, as well as a marginally significant trend for devils with devil facial tumour disease (DFTD) having longer telomeres. A proportional hazard analysis yielded no significant effect of TL on the development of DFTD. Like previous studies, we show the complexity that TL dynamics may exhibit across the lifetime of organisms. Our work highlights the importance of long-term longitudinal sampling for understanding the effects of wildlife diseases on TL.

Quantifying 25 years of disease-caused declines in Tasmanian devil populations: host density drives spatial pathogen spread.

Infectious diseases are strong drivers of wildlife population dynamics, however, empirical analyses from the early stages of pathogen emergence are rare. Tasmanian devil facial tumour disease (DFTD), discovered in 1996, provides the opportunity to study an epizootic from its inception. We use a pattern-oriented diffusion simulation to model the spatial spread of DFTD across the species' range and quantify population effects by jointly modelling multiple streams of data spanning 35 years. We estimate the wild devil population peaked at 53 000 in 1996, less than half of previous estimates. DFTD spread rapidly through high-density areas, with spread velocity slowing in areas of low host densities. By 2020, DFTD occupied >90% of the species' range, causing 82% declines in local densities and reducing the total population to 16 900. Encouragingly, our model forecasts the population decline should level-off within the next decade, supporting conservation management focused on facilitating evolution of resistance and tolerance.

Evaluation of Clinical Properties and Treatment Responses of Infantile Hemangioma.

BACKGROUND: Infantile hemangiomas are the most common vascular tumors in childhood. Although spontaneous regression is common; several infantile hemangioma patients need treatment due to possible morbidities. The aim of this study was to investigate the medical methods used in the treatment of infantile hemangiomas and to evaluate the factors affecting treatment response. METHODS: Clinical and demographic characteristics, risk factors, treatment indications, modalities, duration, and responses of 100 patients between January 2007 and January 2017 were evaluated. RESULTS: The most common form of hemangiomas was superficial lesions. Sixty three per cent of the patients were female. Ulceration and hemorrhage were found in 26% of the cases and ocular problems were detected in 3% of the cases. Among the indications for treatment were cosmetic reasons with 56%, ulcer and bleeding with 25% and risk of vision problems with 13%. Propranolol with/without steroid was used as first line treatment and response rates were: 84 patients with more than 50% response, 9 patients with less than 50% response and 7 patients with treatment refractory. The most important factor affecting the treatment response was age at the beginning of the treatment. Duration of treatment, presence of ulceration, location, and size of hemangioma were also found to have significant effects on responses. CONCLUSIONS: This study demonstrated the importance of the kind and initiation time of infantile hemangioma treatment. A strong positive effect can be reached by starting treatment before the end of the proliferation phase. J Drugs Dermatol. 2020;19(12): doi:10.36849/JDD.2020.5009.

Locally advanced orofacial malignancy: Synopsis of inoperable lesions at an urban tertiary health facility in Nigeria.

BACKGROUND: Locally advanced inoperable orofacial malignancies do present clinically, and constitute a significant public health burden worldwide. OBJECTIVE: To determine the prevalence and clinical characteristics of Stage IV locally advanced inoperable orofacial malignancies for consecutive patients. MATERIALS AND METHODS: A 24-year retrospective study was undertaken, and data obtained from hospital register, case files, and histopathological reports of patients were recorded in a proforma. The variables studied were age, sex, type of lesion and site, duration of lesion, tobacco/alcohol use, and socioeconomic status of the patients and clinical features of the lesions. RESULTS: Twenty-six patients presented, giving a prevalence of 11.2%. The most common lesion was adenoid cystic carcinoma, 23.1%. Males accounted for 18 (69.2%) cases and females, 8 (30.8%) giving a male to female ratio of 2.3:1. The ages ranged from 21 to 65 years, mean (SD) 48.6 (7.3) years. The gender distribution was clinically and statistically significant in favor of the males (P = 0.001). The patients were in the low socioeconomic class and 20 (76.9%) indulged in chronic use of tobacco and alcohol. The duration of the lesions ranged from 1.8 to 3.1 years. The maxilla/facial skin was the commonest site (46.2%). Clinically and statistically, the relativity of site distribution of lesions was significant (P = 0. 002). The clinical features occurred in combination resulting in an average of 10 symptoms and signs in each patient. CONCLUSION: The synopsis of these lesions shows that all have undergone metastasis; salivary gland malignancies were most common with maxilla as the commonest site.

Individual and temporal variation in pathogen load predicts long-term impacts of an emerging infectious disease.

Emerging infectious diseases increasingly threaten wildlife populations. Most studies focus on managing short-term epidemic properties, such as controlling early outbreaks. Predicting long-term endemic characteristics with limited retrospective data is more challenging. We used individual-based modeling informed by individual variation in pathogen load and transmissibility to predict long-term impacts of a lethal, transmissible cancer on Tasmanian devil (Sarcophilus harrisii) populations. For this, we employed approximate Bayesian computation to identify model scenarios that best matched known epidemiological and demographic system properties derived from 10 yr of data after disease emergence, enabling us to forecast future system dynamics. We show that the dramatic devil population declines observed thus far are likely attributable to transient dynamics (initial dynamics after disease emergence). Only 21% of matching scenarios led to devil extinction within 100 yr following devil facial tumor disease (DFTD) introduction, whereas DFTD faded out in 57% of simulations. In the remaining 22% of simulations, disease and host coexisted for at least 100 yr, usually with long-period oscillations. Our findings show that pathogen extirpation or host-pathogen coexistence are much more likely than the DFTD-induced devil extinction, with crucial management ramifications. Accounting for individual-level disease progression and the long-term outcome of devil-DFTD interactions at the population-level, our findings suggest that immediate management interventions are unlikely to be necessary to ensure the persistence of Tasmanian devil populations. This is because strong population declines of devils after disease emergence do not necessarily translate into long-term population declines at equilibria. Our modeling approach is widely applicable to other host-pathogen systems to predict disease impact beyond transient dynamics.

Sex bias in ability to cope with cancer: Tasmanian devils and facial tumour disease.

Knowledge of the ecological dynamics between hosts and pathogens during the initial stages of disease emergence is crucial to understanding the potential for evolution of new interspecific interactions. Tasmanian devil (Sarcophilus harrisii) populations have declined precipitously owing to infection by a transmissible cancer (devil facial tumour disease, DFTD) that emerged approximately 20 years ago. Since the emergence of DFTD, and as the disease spreads across Tasmania, the number of devils has dropped up to 90% across 80% of the species's distributional range. As a result, the disease is expected to act as a strong selective force on hosts to develop mechanisms of tolerance and/or resistance to the infection. We assessed the ability of infected devils to cope with infection, which translates into host tolerance to the cancer, by using the reaction norm of the individual body condition by tumour burden. We found that body condition of infected hosts is negatively affected by cancer progression. Males and females presented significant differences in their tolerance levels to infection, with males suffering declines of up to 25% of their body condition, in contrast to less than 5% in females. Sex-related differences in tolerance to cancer progression may select for changes in life-history strategies of the host and could also alter the selective environment for the tumours.

Dermoscopic features of melanocytic skin lesions in Greek children and adolescents and their association with environmental factors and skin types.

BACKGROUND: Acquired naevi often present in childhood and increase in number and size during early and middle life. As naevi represent potential mimickers of melanoma, the knowledge of their epidemiologic and morphologic characteristics is essential. OBJECTIVE: In this study, we intend to determine the prevalence of dermoscopic patterns of naevi, as well their association with environmental and constitutional factors. METHODS: Cross-sectional data derived from a population-based cohort of children and adolescents aged 6-18 years, from 12 different schools in Thessaloniki, Greece. For each participant, a consent form and a questionnaire were completed, which included data on age, sex, phototype, sun sensitivity, sun exposure, sunscreen use and previous sunburn history. All naevi, their body distribution, and their dermoscopic patterns were recorded. RESULTS: Two thousand and five hundred and five (2505) subjects were enrolled into the study (47.8% males and 52.2% females). The mean number of MN counted in a single person was 29.11 (SD = ±23.863). TNC increased continuously with higher age. Males were found to have a significantly increased number on the trunk (11.7 ± 11.2 and 10.0 ± 8.7, respectively, P < 0.001) and face and neck (6.2 ± 5.3 and 5.1 ± 4.3, respectively, P < 0.001) while females on the upper (10.3 ± 10.1 and 9.3 ± 9.4, respectively, P = 0.008) and lower extremities (2.8 ± 3.4 and 2.5 ± 3.2, respectively, P = 0.008). Globular pattern was the most frequent dominant pattern in lower age groups, and its percentage fell as age increased. On the contrary, the reticular pattern was more often documented in individuals in adolescence. CONCLUSION: This first study of MN in our young population aims to be the basis of further investigation for the MM preventive policy of our state.

Risk factors associated with oral and maxillofacial benign tumors: A case-control study.

This study aimed to investigate the risk factors for oral and maxillofacial benign tumors (OMFBTs). A total of 138 patients diagnosed with OMFBTs between September 2010 and September 2015 were retrospectively analyzed. Clinical data including demographic characteristics, smoking and drinking status, dietary habit, oral hygiene and tumor related family history were collected and compared with 134 cases of healthy people who visited the hospital for physical examination during the same time. Logistic regression analysis was performed for multivariable regression analysis. OMFBTs was associated with smoking more than 20 cigarettes per day, accumulated cigarette consumption more than 30, accumulated cigarette package consumption more than 1000, present smoking and drinking, passive smoking before 18 years old, initial smoking age more than 20 years old and alcohol consumption more than 50 g/d (P < 0.05). Consumption of meat, fish, seafood, fruits and vitamin tablets were associated with lower risk of OMFBTs. Non-conditional logistic regression analyses indicated that the independent risk factors of OMFBTs included accumulated cigarette consumption, passive smoking before the age of 18, meat-free, fish-free, fruit-free, vitamin tablets-free, frequency of tooth brushing lower than once a day, not routinely attending oral examination, wearing denture and drinking alcohol (P < 0.05). Smoking and drinking should be discouraged in dental patients. Keeping a good dietary habit and routinely attending oral examination are highly encouraged.

Seven Non-melanoma Features to Rule Out Facial Melanoma.

Facial melanoma is difficult to diagnose and dermatoscopic features are often subtle. Dermatoscopic non-melanoma patterns may have a comparable diagnostic value. In this pilot study, facial lesions were collected retrospectively, resulting in a case set of 339 melanomas and 308 non-melanomas. Lesions were evaluated for the prevalence (> 50% of lesional surface) of 7 dermatoscopic non-melanoma features: scales, white follicles, erythema/reticular vessels, reticular and/or curved lines/fingerprints, structureless brown colour, sharp demarcation, and classic criteria of seborrhoeic keratosis. Melanomas had a lower number of non-melanoma patterns (p< 0.001). Scoring a lesion suspicious when no prevalent non-melanoma pattern is found resulted in a sensitivity of 88.5% and a specificity of 66.9% for the diagnosis of melanoma. Specificity was higher for solar lentigo (78.8%) and seborrhoeic keratosis (74.3%) and lower for actinic keratosis (61.4%) and lichenoid keratosis (25.6%). Evaluation of prevalent non-melanoma patterns can provide slightly lower sensitivity and higher specificity in detecting facial melanoma compared with already known malignant features.

Microcystic Adnexal Carcinoma: A Review of the Literature.

BACKGROUND: Microcystic adnexal carcinoma (MAC) is a rare, locally aggressive cutaneous neoplasm that commonly occurs on the face. OBJECTIVE: The purpose of this article is to comprehensively review the current literature on MAC pertaining to epidemiology, pathogenesis, clinical presentation, histology, immunohistochemistry, prognosis, follow-up, and treatment. MATERIALS AND METHODS: An extensive literature review was conducted using OVID MEDLINE and PubMed to identify articles relating to MAC. RESULTS: Microcystic adnexal carcinoma typically presents as a skin-colored nodule on the face. The pathogenesis is mostly related to pilar and eccrine differentiation. Histologically, MAC can mimic syringoma, desmoplastic trichoepithelioma, and infiltrative basal cell carcinoma. Diagnosis is challenging because superficial shave biopsies may reveal only benign findings that do not warrant further management. A deep biopsy is mandatory for the correct diagnosis, and Mohs micrographic surgery provides the highest cure rate. CONCLUSION: Microcystic adnexal carcinoma is a locally aggressive disease with histological margins that often far surpass what is clinically suspected. Mohs micrographic surgery is the standard of care for removal of these lesions. Patients with a history of MAC should be examined at least every 6 months for recurrence, metastasis, and development of additional skin cancers.

Disease-induced decline of an apex predator drives invasive dominated states and threatens biodiversity.

Apex predators are important in protecting biodiversity through top-down influence on food webs. Their loss is linked with competitive release of invasive mesopredators and species extinctions. The Tasmanian devil (Sarcophilus harrisii) has experienced severe declines over a 15-yr period as a novel transmissible cancer has spread across its current geographic range. We surveyed the mammalian community, using hair traps, across the spatial extent of the devil's progressive population decline. We found increased activity of alien invasive species (feral cats, black rats), and reduced small and medium-sized native prey species in response to the timing of the decline. In areas of long-term devil decline, invasive species comprised a significantly larger proportion of the community. The results provide evidence that the devil plays a keystone role in Tasmania's ecosystem with their decline linked to a shift toward an invasive state and biodiversity loss in one of Australia's most intact faunal communities.

Devil Facial Tumor Disease.

Devil facial tumor disease (DFTD) is an emergent transmissible cancer exclusive to Tasmanian devils (Sarcophilus harrisii) and threatening the species with extinction in the wild. Research on DFTD began 10 years ago, when nothing was known about the tumor and little about the devils. The depth of knowledge gained since then is impressive, with research having addressed significant aspects of the disease and the devils' responses to it. These include the cause and pathogenesis of DFTD, the immune response of the devils and the immune evasion mechanisms of the tumor, the transmission patterns of DFTD, and the impacts of DFTD on the ecosystem. This review aims to collate this information and put it into the context of conservation strategies designed to mitigate the impacts of DFTD on the devil and the Tasmanian ecosystem.

Transmissible cancer in Tasmanian devils: localized lineage replacement and host population response.

Tasmanian devil facial tumour disease (DFTD) is a clonally transmissible cancer threatening the Tasmanian devil (Sarcophilus harrisii) with extinction. Live cancer cells are the infectious agent, transmitted to new hosts when individuals bite each other. Over the 18 years since DFTD was first observed, distinct genetic and karyotypic sublineages have evolved. In this longitudinal study, we investigate the associations between tumour karyotype, epidemic patterns and host demographic response to the disease. Reduced host population effects and low DFTD infection rates were associated with high prevalence of tetraploid tumours. Subsequent replacement by a diploid variant of DFTD coincided with a rapid increase in disease prevalence, population decline and reduced mean age of the population. Our results suggest a role for tumour genetics in DFTD transmission dynamics and epidemic outcome. Future research, for this and other highly pathogenic emerging infectious diseases, should focus on understanding the evolution of host and pathogen genotypes, their effects on susceptibility and tolerance to infection, and their implications for designing novel genetic management strategies. This study provides evidence for a rapid localized lineage replacement occurring within a transmissible cancer epidemic and highlights the possibility that distinct DFTD genetic lineages may harbour traits that influence pathogen fitness.

Age, gender, and topography influence the clinical and dermoscopic appearance of lentigo maligna.

BACKGROUND: Little is known about the frequency of clinical and dermoscopic patterns of lentigo maligna (LM) in relation to specific anatomic subsites and patients characteristics. OBJECTIVE: We sought to assess the frequency of clinical and dermoscopic features of LM and to correlate them to specific anatomic subsites, and patients' age and gender. METHODS: This was a retrospective analysis of clinical and dermoscopic images of a series of consecutive, histopathologically diagnosed, facial and extrafacial LM. RESULTS: A total of 201 cases from 200 patients (mean age 69.51 ± 12.26 years) including 120 women were collected. Most cases were located on the face (n = 192, 95.5%). In 102 cases, LM presented as clinically solitary facial macule (s/LM), whereas it was associated with multiple surrounding freckles in the remaining cases. s/LM were significantly smaller (<10 vs >10 mm; P = .020) and associated with younger age compared with LM associated with multiple surrounding freckles (mean age 67.73 ± 12.68 years vs 71.34 ± 11.59 years, respectively; P = .036). Dermoscopically, gray color irrespective of a specific pattern was the most prevalent finding seen in 178 (88.6%) cases. LIMITATIONS: This was a retrospective study. CONCLUSIONS: The knowledge about patient age, patient gender, and site-related clinical features of LM associated with gray color upon dermoscopy may enhance the clinical recognition of LM.

The 5-year prevalence of maxillofacial fibro-osseous lesions in Uganda.

BACKGROUND: Fibro-osseous lesions of the jaws are a diagnostic challenge for the pathologist because histologically, they are not easily distinguishable. African data on the prevalence of these lesions are scarce. We present a 5-year report of benign fibro-osseous lesions at Mulago Hospital, Uganda, showing the frequency and distribution of these lesions. MATERIALS AND METHODS: Confirmed fibro-osseous lesions reports at the pathology department (2007-2012) were retrieved. Patients' clinical data including age, gender, anatomic location, and diagnosis were recorded. Descriptive statistics and simple proportion tests were carried out. RESULTS: We retrieved 155 confirmed benign fibro-osseous lesions over this period, 65% were females, 34% males, and the gender of one case was not specified. Fibrous dysplasia was the most prevalent lesion (n = 87, 56.1%) followed by ossifying fibroma (n = 50, 32.9%) and osseous dysplasia (n = 17, 10.9%). We neither found craniofacial nor polyostotic fibrous dysplasia. Fibrous dysplasia and ossifying fibroma peaked in the second decade at 40.2% and 40.0%, respectively. Florid osseous dysplasia was commonest in the fifth decade. CONCLUSION: In this study, all the florid osseous dysplasia were seen among females. We need to carry out prospective studies to establish as to why and what kind of women get afflicted by this lesion.

Age-related prevalence and morphological appearance of facial skin tumours: a prospective, cross-sectional, observational, multicentre study with special emphasis on melanocytic tumours.

BACKGROUND: The clinical and histopathological diagnosis of skin tumours arising on the face may be challenging. OBJECTIVE: An improved knowledge about the age-related patterns of facial skin tumours may aid the correct diagnosis and management. METHODS: We conducted a prospective, cross-sectional morphological study to investigate the age-related frequency and morphological variability in facial skin tumours in a cohort of consecutive subjects attending two skin lesion clinics in Italy between June and September 2011. A total of 454 consecutive subjects (249 women; 55.5%) presenting with a total of 1866 facial tumours were enrolled in the study. Of the entire cohort, 54 (11.9%) subjects had no facial lesion. RESULTS: Total body naevus count correlated significantly with the mean number of facial lesions (ρ = 0.289, P < 0.001). The majority of flat lesions were pigmented (1056; 75.70%), compared to palpable (233; 17.40%) and raised lesions (93; 6.90%), the association being statistically significant (Pearson's chi square, P < 0.001. Considering melanocytic tumours only, the frequency of flat lesions significantly decreased with increasing age, while the number of palpable and raised lesions increased with increasing age (chi-square, P < 0.001). This trend was mainly due to naevi, whereby pigmented melanocytic naevi decreased with increasing age. Conversely, the percentage of non- pigmented naevi increased with increasing age (chi-square, P < 0.001). LIMITATIONS: The study was conducted in skin lesion clinics in Italy, thus any general conclusions with respect to common traits or features based on the phenotypic and genetic diversity within the European population cannot be stated. CONCLUSIONS AND RELEVANCE: Our study suggests that a high number of facial naevi could predict a high total naevus count. Moreover, naevi present a different morphological appearance during lifetime being initially flat, small and pigmented and becoming later raised, large and hypopigmented. Instead, lentigo maligna is an intraepidermal proliferation that typically presents as flat, large pigmented macule. A given histopathological diagnosis of a junctional naevus of a flat, facial pigmented macule of an elderly should be critically reviewed and treated with caution.