Demographic patterns of cutaneous T-cell lymphoma incidence in Texas based on two different cancer registries

From Molecules to Microbes: Tracing Cutaneous T-Cell Lymphoma Pathogenesis through Malignant Inflammation

The etiology of CTCL is a subject of extensive investigation. Researchers have explored links between CTCL and environmental chemical exposures, such as aromatic hydrocarbons (eg, pesticides and benzene), as well as infectious factors, including various viruses (eg, human T-lymphotropic virus [HTLV]-I and HTLV-II) and bacteria (eg, Staphylococcus aureus). There has been growing emphasis on the role of malignant inflammation in CTCL development. In this review, we synthesize studies of environmental and infectious exposures, along with research on the aryl hydrocarbon receptor and the involvement of pathogens in disease etiology, providing insight into the pathogenesis of CTCL.

Clusters, crop dusters, and myth busters: a scoping review of environmental exposures and cutaneous T-cell lymphoma

INTRODUCTION

Cutaneous T-cell lymphoma (CTCL) is a heterogenous group of non-Hodgkin lymphomas. Similar presentation to benign conditions, significant genetic variation, and lack of definitive biomarkers contributes to diagnostic delay. The etiology of CTCL is unknown, and environmental exposures, such as geographic, occupational, chemicals, sunlight, and insects have been investigated.

EVIDENCE ACQUISITION

Review of the literature for CTCL and exposures was performed in PubMed and Google Scholar in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Extension for Scoping Reviews. This search yielded 193 total results, which were initially screened with defined inclusion and exclusion criteria. The 45 remaining articles were reviewed and classified by exposure type.

EVIDENCE SYNTHESIS

The most frequently investigated CTCL exposure type was geographic (13/45 articles, 29%). Chemical exposures were commonly discussed (10/45 articles, 22%), along with occupational (10/45 articles, 22%). Insect exposures (6/45, 13%) and sun exposure (3/45, 7%) were also reviewed, along with articles describing multiple exposure types (3/45, 7%). Article types ranged from cases to systematic reviews and case-control studies. Evidence linking CTCL and these exposures was mixed. Limitations of this investigation include reliance on patient reporting and frequent speculation on disease association versus causality.

CONCLUSIONS

This investigation synthesizes the current literature on exposures potentially implicated in the pathogenesis of CTCL, while offering guidance on patient history-taking to ensure potential exposures are captured. Awareness of these possible associations may improve understanding of disease pathogenesis and diagnosis. Moreover, these insights may help with public health decision-making and disease mitigation.

Variations in genetics, biology, and phenotype of cutaneous disorders in skin of color. Part II: Differences in clinical presentation and disparities in cutaneous disorders in skin of color

Skin of color (SOC) patients are projected to comprise the majority of the population by 2044, yet knowledge gaps in the clinical presentation and treatment of both common and uncommon dermatologic conditions in skin of color persist. Improved awareness of disparities that disproportionately impact SOC patients is necessary to address health inequity in the field of dermatology. The first part of this CME discussed structural, genetic, and immunophenotypic differences in SOC in common inflammatory disorders as well as cutaneous malignancies. The second part of this CME highlights clinical differences in the phenotypic presentation of the inflammatory disorders of atopic dermatitis, psoriasis, and hidradenitis suppurativa as well as the cutaneous malignancies of melanoma, basal cell carcinoma, and cutaneous T-cell lymphoma. Health disparities associated with each of these conditions are also discussed.

Molecular pathogenesis of Cutaneous T cell Lymphoma: Role of chemokines, cytokines, and dysregulated signaling pathways

Cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of lymphoproliferative neoplasms that exhibit a wide spectrum of immune-phenotypical, clinical, and histopathological features. The biology of CTCL is complex and remains elusive. In recent years, the application of next-generation sequencing (NGS) has evolved our understanding of the pathogenetic mechanisms, including genetic aberrations and epigenetic abnormalities that shape the mutational landscape of CTCL and represent one of the important pro-tumorigenic principles in CTCL initiation and progression. Still, identification of the major pathophysiological pathways including genetic and epigenetic components that mediate malignant clonal T cell expansion has not been achieved. This is of prime importance given the role of malignant T cell clones in fostering T helper 2 (Th2)-bias tumor microenvironment and fueling progressive immune dysregulation and tumor cell growth in CTCL patients, manifested by the secretion of Th2-associated cytokines and chemokines. Alterations in malignant cytokine and chemokine expression patterns orchestrate the inflammatory milieu and influence the migration dynamics of malignant clonal T cells. Here, we highlight recent insights about the molecular mechanisms of CTCL pathogenesis, emphasizing the role of cytokines, chemokines, and associated downstream signaling networks in driving immune defects, malignant transformation, and disease progression. In-depth characterization of the CTCL immunophenotype and tumoral microenvironment offers a facile opportunity to expand the therapeutic armamentarium of CTCL, an intractable malignant skin disease with poor prognosis and in dire need of curative treatment approaches.

Epidemiologic Trends of Cutaneous T-Cell Lymphoma in Arkansas Reveals Demographic Disparities

Accurate demographic data are critical for comprehending and treating cutaneous T-cell lymphoma (CTCL). Our research aimed to determine the demographics and incidence trends of CTCL patients in Arkansas compared to those of the national CTCL population to recognize the underlying disparities. We collected data from 143 CTCL patients at the University of Arkansas for Medical Sciences (UAMS) and national CTCL patient data from the Surveillance, Epidemiology, and End Results (SEER) database. Our analysis revealed that males are affected more than females across all ages and races. CTCL incidence and mortality data show that CTCL has a steady increase at the national level and in Arkansas while disproportionately affecting the young black male population. In Arkansas, more than one-third of black patients presented at an advanced stage (IIB+) compared to one-fifth in the white population, and the mean age of death was more than a decade younger for black (60 years) than for white patients (74.6 years). Nationally, black male patients had the greatest mortality rate (0.5) compared to 0.32 for white males. CTCL is 2.23 and 2.38 times more prevalent in urban versus rural areas in Arkansas and nationally, respectively. Most Arkansas patients reside near major interstates and chemical-emitting sites. In conclusion, our demographic analysis of Arkansas and national CTCL patients verifies recent trends toward more aggressive presentations in young black male patients, and our geographic findings suggest possible environmental risk factors.

Understanding Cell Lines, Patient-Derived Xenograft and Genetically Engineered Mouse Models Used to Study Cutaneous T-Cell Lymphoma

Cutaneous T cell lymphoma (CTCL) is a spectrum of lymphoproliferative disorders caused by the infiltration of malignant T cells into the skin. The most common variants of CTCL include mycosis fungoides (MF), Sézary syndrome (SS) and CD30⁺ Lymphoproliferative disorders (CD30⁺ LPDs). CD30⁺ LPDs include primary cutaneous anaplastic large cell lymphoma (pcALCL), lymphomatoid papulosis (LyP) and borderline CD30⁺ LPD. The frequency of MF, SS and CD30⁺ LPDs is ~40–50%, <5% and ~10–25%, respectively. Despite recent advances, CTCL remains challenging to diagnose. The mechanism of CTCL carcinogenesis still remains to be fully elucidated. Hence, experiments in patient-derived cell lines and xenografts/genetically engineered mouse models (GEMMs) are critical to advance our understanding of disease pathogenesis. To enable this, understanding the intricacies and limitations of each individual model system is highly important. Presently, 11 immortalized patient-derived cell lines and different xenograft/GEMMs are being used to study the pathogenesis of CTCL and evaluate the therapeutic efficacy of various treatment modalities prior to clinical trials. Gene expression studies, and the karyotyping analyses of cell lines demonstrated that the molecular profile of SeAx, Sez4, SZ4, H9 and Hut78 is consistent with SS origin; MyLa and HH resemble the molecular profile of advanced MF, while Mac2A and PB2B represent CD30⁺ LPDs. Molecular analysis of the other two frequently used Human T-Cell Lymphotropic Virus-1 (HTLV-1)⁺ cell lines, MJ and Hut102, were found to have characteristics of Adult T-cell Leukemia/Lymphoma (ATLL). Studies in mouse models demonstrated that xenograft tumors could be grown using MyLa, HH, H9, Hut78, PB2B and SZ4 cells in NSG (NOD Scid gamma mouse) mice, while several additional experimental GEMMs were established to study the pathogenesis, effect of drugs and inflammatory cytokines in CTCL. The current review summarizes cell lines and xenograft/GEMMs used to study and understand the etiology and heterogeneity of CTCL.

Transcriptional Heterogeneity and the Microbiome of Cutaneous T-Cell Lymphoma

Cutaneous T-Cell Lymphomas (CTCL) presents with substantial clinical variability and transcriptional heterogeneity. In the recent years, several studies paved the way to elucidate aetiology and pathogenesis of CTCL using sequencing methods. Several T-cell subtypes were suggested as the source of disease thereby explaining clinical and transcriptional heterogeneity of CTCL entities. Several differentially expressed pathways could explain disease progression. However, exogenous triggers in the skin microenvironment also seem to affect CTCL status. Especially Staphylococcus aureus was shown to contribute to disease progression. Only little is known about the complex microbiome patterns involved in CTCL and how microbial shifts might impact this malignancy. Nevertheless, first hints indicate that the microbiome might at least in part explain transcriptional heterogeneity and that microbial approaches could serve in diagnosis and prognosis. Shaping the microbiome could be a treatment option to maintain stable disease. Here, we review current knowledge of transcriptional heterogeneity of and microbial influences on CTCL. We discuss potential benefits of microbial applications and microbial directed therapies to aid patients with CTCL burden.

Mycosis fungoides and Sézary syndrome

Mycosis fungoides (MF) and Sézary syndrome (SS) are primary cutaneous T-cell lymphomas (CTCL) with not yet fully understood etiology and pathogenesis. Conceptually, MF and SS are classified as distinct entities arising from different T helper cell subsets. MF is the most common CTCL entity, while SS is very rare. MF presents clinically with patch, plaque and/or tumor stages, but can also evolve as erythroderma, which in turn is pathognomonic for SS. SS is characterized by a detectable tumor-cell burden (Sézary cells) in the peripheral blood consistent with advanced-stage disease and a poor prognosis. In early-stage disease of MF, which is the predominant form, the prognosis is generally favorable. However, in up to 30 % of patients, there is progression of skin lesions, which can ultimately lead to visceral involvement. The histological manifestation of MF can be subtle in early-stage disease and therefore a careful clinicopathological correlation is paramount. The treatment of MF/SS is dependent on the disease stage. Therapeutic options include both skin-directed and systemic regimens. Apart from allogeneic stem cell transplantation (alloSCT), there is as yet no curative therapy for MF/SS. Accordingly, the treatment approach is symptom oriented and aims to reduce the tumor burden and improve health-related quality of life. However, the therapeutic landscape for CTCL is constantly being expanded by the discovery of novel therapeutic targets.

Cutaneous T-cell lymphoma in Asian patients: a multinational, multicenter, prospective registry study in Asia

Cutaneous T-cell lymphomas (CTCLs) are a group of T-cell lymphomas with low incidence. Due to their indolent characteristics, treatment strategies have not yet been established for advanced CTCLs. In this study, relative incidence of CTCLs in Asia was estimated and the therapeutic outcomes presented based on various treatments currently used in clinics for advanced CTCLs. As part of a prospective registry study of peripheral T-cell lymphoma (PTCL) conducted across Asia, including Korea, China, Taiwan, Singapore, Malaysia, and Indonesia, subgroup analysis was performed for patients with CTCLs. Among 486 patients with PTCL, 37 with CTCL (7.6%) were identified between April 2016 and February 2019. Primary cutaneous ALK-negative anaplastic large cell lymphoma (ALCL, 35.1%) was the most common subtype. With a median follow-up period of 32.1 months, median progression-free survival (PFS) was 53.5 months (95% CI 0.0-122.5), and overall survival was not reached. 14 patients (48.2%) underwent subsequent treatment after the first relapse, but the response rate was 20% with a PFS of 2.2 months (95% CI 0.3-4.0). Six patients received autologous stem cell transplantation (auto-SCT). However, auto-SCT did not result in better outcomes. Additional studies are needed on standard care treatment of advanced or refractory and relapsed CTCLs.

Geographic clustering of cutaneous T-cell lymphoma in New Jersey: an exploratory analysis using residential histories

PURPOSE

Cutaneous T-cell lymphoma (CTCL) is a rare type of non-Hodgkin lymphoma. Previous studies have reported geographic clustering of CTCL based on the residence at the time of diagnosis. We explore geographic clustering of CTCL using both the residence at the time of diagnosis and past residences using data from the New Jersey State Cancer Registry.

METHODS

CTCL cases (n = 1,163) diagnosed between 2006-2014 were matched to colon cancer controls (n = 17,049) on sex, age, race/ethnicity, and birth year. Jacquez's Q-Statistic was used to identify temporal clustering of cases compared to controls. Geographic clustering was assessed using the Bernoulli-based scan-statistic to compare cases to controls, and the Poisson-based scan-statisic to compare the observed number of cases to the number expected based on the general population. Significant clusters (p < 0.05) were mapped, and standard incidence ratios (SIR) reported. We adjusted for diagnosis year, sex, and age.

RESULTS

The Q-statistic identified significant temporal clustering of cases based on past residences in the study area from 1992 to 2002. A cluster was detected in 1992 in Bergen County in northern New Jersey based on the Bernoulli (1992 SIR 1.84) and Poisson (1992 SIR 1.86) scan-statistics. Using the Poisson scan-statistic with the diagnosis location, we found evidence of an elevated risk in this same area, but the results were not statistically significant.

CONCLUSION

There is evidence of geographic clustering of CTCL cases in New Jersey based on past residences. Additional studies are necessary to understand the possible reasons for the excess of CTCL cases living in this specific area some 8-14 years prior to diagnosis.

Staphylococcus aureus Induces Signal Transducer and Activator of Transcription 5‒Dependent miR-155 Expression in Cutaneous T-Cell Lymphoma

Staphylococcal enterotoxins are believed to fuel disease activity in cutaneous T-cell lymphoma. Recent data support this by showing that antibiotics inhibit malignant T cells in skin lesions in mycosis fungoides and Sézary syndrome, the most common forms of cutaneous T-cell lymphoma. Yet, it remains incompletely characterized how staphylococcal enterotoxins fuel disease activity. In this study, we show that staphylococcal enterotoxins induce the expression of the oncogenic microRNA miR-155 in primary malignant T cells. Thus, staphylococcal enterotoxins and Staphyloccocus aureus isolates from lesional skin of patients induce miR-155 expression at least partly through the IL-2Rg‒Jak‒signal transducer and activator of transcription 5 pathway, and the effect is augmented by the presence of nonmalignant T cells. Importantly, mycosis fungoides lesions harbor S. aureus, express Y-phosphorylated signal transducer and activator of transcription 5, and display enhanced miR-155 expression, when compared with nonlesional and healthy skin. Preliminary data show that aggressive antibiotic therapy is associated with decreased Y-phosphorylated signal transducer and activator of transcription 5 and miR-155 expression in lesional skin in two patients with Sézary syndrome. In conclusion, we show that S. aureus and its enterotoxins induce enhanced expression of oncogenic miR-155, providing mechanistic insight into the role of S. aureus in cutaneous T-cell lymphoma. Our findings support that environmental stimuli such as bacteria can fuel disease progression in cutaneous T-cell lymphoma.

Patient-reported quality of life in patients with relapsed/refractory cutaneous T-cell lymphoma: Results from the randomised phase III ALCANZA study

BACKGROUND

Brentuximab vedotin was approved for adult patients with CD30-expressing cutaneous T-cell lymphoma treated with prior systemic therapy based on improved response rates and progression-free survival with brentuximab vedotin (1.8 mg/kg once every 3 weeks; ≤16 cycles) versus physician's choice (methotrexate/bexarotene; ≤48 weeks) in the phase III ALCANZA study. Quality of life (QoL) in ALCANZA patients was also examined.

METHODS

QoL measures in ALCANZA were based on the Skindex-29, Functional Assessment of Cancer Therapy-General (FACT-G) and European QoL 5-dimension (EQ-5D) questionnaires.

RESULTS

Mean maximum reduction from the baseline Skindex-29 symptom domain score (key secondary end-point) was greater with brentuximab vedotin than physician's choice (-27.96 versus -8.62); the difference, -18.9 (95% confidence interval -26.6, -11.2; adjusted p < 0.001), exceeded the study-defined minimally important difference (9.0-12.3). Mean changes from baseline to end-of-treatment visit total FACT-G scores were similar with brentuximab vedotin and physician's choice (0.15 versus -2.29). EQ-5D changes were also comparable between arms. Among brentuximab vedotin-treated patients with peripheral neuropathy (PN), mean maximum reduction in Skindex-29 symptom domain was -35.54 versus -11.11 in patients without PN. PN had no meaningful effect on FACT-G and EQ-5D QoL scores.

CONCLUSIONS

In summary, brentuximab vedotin produced superior reductions in symptom burden compared with physician's choice, without adversely impacting QoL. QoL was unaffected by the presence of PN in brentuximab vedotin-treated patients.

CLINICAL TRIAL REGISTRATION

NCT01578499.

Investigating epidemiologic trends and the geographic distribution of patients with anal squamous cell carcinoma throughout Canada

Background

Anal cancer is a rare disease, constituting 0.5% of new cancer cases in the United States. The most common subtype is squamous cell carcinoma (scc). Studies in several developed nations have reported on an increasing incidence of anal cancer in recent decades, and various risk factors pertaining to the pathogenesis of the disease have been identified, including infection with the human papillomavirus, tobacco use, and immunosuppression. The epidemiology and distribution of anal scc throughout Canada remain poorly understood, however.

Methods

Using 3 population-based cancer registries, a retrospective analysis of demographic data across Canada for 1992-2010 was performed. The incidence and mortality for anal scc was examined at the levels of provinces, cities, and the forward sortation area (FSA) component (first 3 characters) of postal codes.

Results

During 1992-2010, 3720 individuals were diagnosed with anal scc in Canada; 64% were women. The overall national incidence rate was 6.3 cases per million population per year, with an average age at diagnosis of 60.4 years. The incidence increased over time, with significantly higher incidence rates documented in British Columbia and Nova Scotia (9.3 cases per million population each). Closer examination revealed clustering of cases in various urban centres and self-identified lgbtq communities in Toronto, Montreal, and Vancouver.

Discussion

This study provides, for the first time, a comprehensive analysis of the burden of anal scc in Canada, identifying susceptible populations and shedding light onto novel avenues of research to lower the incidence of anal cancer throughout the country.

Epidemiology and Patient Distribution of Oral Cavity and Oropharyngeal SCC in Canada

BACKGROUND

Oral cavity cancers (OCCs) and oropharyngeal cancers (OPCs) continue to be a major source of morbidity and mortality worldwide requiring the shared effort of numerous specialists. Tobacco and alcohol consumption have long been identified as risk factors for both OCC and OPC. In addition, human papilloma virus (HPV) is gaining its position as the main causal agent for OPC.

OBJECTIVE

The objective of this study is to analyze the epidemiology of OCC and OPC in Canada.

METHODS

Data pertaining to the year of diagnosis, the patient's sex, age at the time of diagnosis, province/territory, city and postal code of oral cavity, and oropharyngeal malignancies diagnosed during 1992-2010 were extracted from the Canadian Cancer Registry and Le Registre Québécois du Cancer.

RESULTS

In total, 21 685 OCC cases and 15 965 OPC cases were identified from 1992 to 2010. Of those, 84.97% were oral cavity squamous cell carcinomas (SCCs), 88.10% were oropharyngeal SCCs, and both had a significant male predominance. While oral cavity SCC incidence stabilized over the study period, oropharyngeal SCC continued to increase. Oral cavity SCC incidence increased with age, while oropharyngeal SCC incidence peaked in the 50- to 59-year age group. Detailed geographic distribution analysis of patients at the provincial/territorial, city, and postal code levels identified several patient clusters.

CONCLUSIONS

This work highlights important epidemiological differences in trends between oral and oropharyngeal cancers, identifies high-incidence postal codes for each malignancy, and correlates incidence/mortality with known risk factors including alcohol/tobacco use and HPV infections, therefore providing a comprehensive understanding of epidemiology for these cancers in Canada.

Insights Into the Molecular and Cellular Underpinnings of Cutaneous T Cell Lymphoma

Cutaneous T cell lymphoma (CTCL) is a rare malignancy of skin-homing T lymphocytes. Advances in whole exome sequencing have identified a vast number of both single nucleotide variants (SNVs) and genomic copy number alterations (GCNAs) as driver mutations present in CTCL cells. These alterations cluster within several key pathways - T cell/NF-κB/JAK-STAT activation, cell cycle dysregulation/apoptosis, and DNA structural dysregulation affecting gene expression - allowing the maintenance of a population of proliferating, activated malignant T lymphocytes. While much of the clinical spectrum, genetic alterations, and oncogenic behavior of CTCL have been elucidated, little is known about the etiology that underlies CTCL malignant transformation and progression. Herein, we review the epidemiology, clinical presentation, and pathophysiology of CTCL to provide a perspective on CTCL pathogenesis. We outline a series of alterations by which mature, activated T lymphocytes are endowed with apoptosis resistance and cutaneous persistence. Subsequent genomic alterations including the loss of chromosomal structural controls further promote proliferation and constitutive T cell activation. CTCL cells are both malignant cells and highly functional T cells that can have major cutaneous and immunologic effects on the patient, including the suppression of cell-mediated immunity that facilitates malignant cell expansion. A deeper understanding of the molecular and cellular underpinnings of CTCL can help guide clinical management as well as inform prognosis and therapeutic discovery.

Clustering of cutaneous T-cell lymphoma is associated with increased levels of the environmental toxins benzene and trichloroethylene in the state of Georgia

BACKGROUND

Cutaneous T-cell lymphoma (CTCL) is a rare form of non-Hodgkin lymphoma arising in the skin. Geographic clustering of CTCL has recently been reported, but its association with environmental factors is unknown. Benzene and trichloroethylene (TCE) are environmental toxins with carcinogenic properties. The authors investigated associations between geographic clustering of CTCL incidence in the state of Georgia with benzene and TCE exposure.

METHODS

The statewide county-level incidence of CTCL within Georgia was obtained from the Georgia Cancer Registry for the years 1999 to 2015. Standardized incidence ratios (SIRs) were calculated by dividing observed cases by expected cases using national incidence rates by age, sex, and race. Clustering of CTCL was analyzed using spatial analyses. County-level concentrations of benzene and TCE between 1996 and 2014 were collected from the Environmental Protection Agency's National Air Toxics Assessment database. Linear regression analyses on CTCL incidence were performed comparing SIRs with levels of benzene and TCE by county.

RESULTS

There was significant geographic clustering of CTCL in Georgia, particularly around Atlanta, which was correlated with an increased concentration of benzene and TCE exposure. Among the 4 most populous counties in Georgia, CTCL incidence was between 1.2 and 1.9 times higher than the state average, and benzene and TCE levels were between 2.9 and 8.8 times higher.

CONCLUSIONS

The current results demonstrate nonrandom geographic clustering of CTCL incidence in Georgia. To the authors' knowledge, this is the first analysis to identify a correlation between geographic clustering of CTCL and environmental toxic exposures.

Identification of significant geographic clustering of polycythemia vera cases in Montreal, Canada

BACKGROUND

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm associated at times with debilitating symptoms and a significant mortality rate. Understanding the demographics, epidemiology, and geography of this disease may provide further insight into important risk factors associated with its development. The objective of this study was to analyze patient demographics, incidence, and mortality rates, as well as the geographic distribution of PV patients in Canada between 1992 and 2010.

METHODS

This study was achieved by analyzing the Canadian Cancer Registry, Le Registre Québécois du Cancer, and the Canadian Vital Statistics patient databases.

RESULTS

A total of 4645 patients were diagnosed with PV between 1992 and 2010. While the annual incidence rate of this cancer fluctuated in Canada, mortality rate analysis indicated a decreasing trend. Geographically, PV incidence rates were notably elevated in the province of Quebec compared with the Canadian average. Further analysis of high-incidence forward sortation areas indicated a striking clustering of cases in the H4W region encompassing the Côte-Saint-Luc borough of Montreal, with an incidence of 102.97 (95% confidence interval, 75.11-137.79) cases per million per year, which is >13 times the national average.

CONCLUSION

The residential area of Côte-Saint-Luc is an important PV cluster in Canada, with high concentration of retirement homes and geriatric hospices. Also, Jewish residents comprise >60% of the population in this neighborhood. These findings suggest that an older age and, potentially, an inherent genetic predisposition may be implicated in the pathogenesis of this malignancy. This study provides a comprehensive overview of PV burden/geographic distribution of cases in Canada.

Environmental and Other Extrinsic Risk Factors Contributing to the Pathogenesis of Cutaneous T Cell Lymphoma (CTCL)

The applications of disease cluster investigations in medicine have developed rather rapidly in recent decades. Analyzing the epidemiology of non-random aggregation of patients with a particular disease fostered identification of environmental and external exposures as disease triggers and promoters. Observation of patient clusters and their association with nearby exposures, such as Dr. John Snow's astute mapping analysis in the mid-1800's, which revealed proximity of cholera patients in London to a contaminated water pump infected with Vibrio cholerae, have paved the way for the field of epidemiology. This approach enabled the identification of triggers for many human diseases including infections and cancers. Cutaneous T-cell lymphomas (CTCL) represent a group of non-Hodgkin lymphomas that primarily affect the skin. The detailed pathogenesis by which CTCL develops remains largely unknown. Notably, non-random clustering of CTCL patients was reported in several areas worldwide and this rare malignancy was also described to affect multiple members of the same family. These observations indicate that external factors are possibly implicated in promoting CTCL lymphomagenesis. Here, we review the epidemiology of CTCL worldwide and the clinical characteristics of CTCL patients, as revealed by global epidemiological data. Further, we review the known risk factors including sex, age, race as well as environmental, infectious, iatrogenic and other exposures, that are implicated in CTCL lymphomagenesis and discuss conceivable mechanisms by which these factors may trigger this malignancy.

Dermoscopy of Lymphomas and Pseudolymphomas

Primary cutaneous lymphomas are a heterogeneous group that includes 2 main groups of primary T- and B-cell lymphomas, which can involve the skin with distinct variability in clinical presentation, histopathology, immunophenotypes, molecular signature, and prognosis. The authors describe the most frequent clinical forms of cutaneous lymphomas and their dermoscopic features. Even if the diagnosis of these entities is still based on a cellular level and the literature on dermoscopy in cutaneous lymphomas is limited and, for several entities it is based only on single case reports/case series, we think that know how they appear also in dermoscopy can be useful for helping in the clinical diagnosis.

Gene expression profiling and immune cell-type deconvolution highlight robust disease progression and survival markers in multiple cohorts of CTCL patients

CTCL follows different courses depending on the clinical stage at the time of diagnosis. Patients with early stage Mycosis Fungoides (MF) variant of CTCL may experience an indolent course over decades, whereas patients with advanced MF and Sézary Syndrome (SS) disease at diagnosis, often succumb within 5 years. Even within early stage CTCL/MF, a minority of patients will progress to more advanced stages. We recently generated RNA sequencing data on 284 CTCL-relevant genes for 157 patients and identified differentially expressed genes across stages I-IV. In this study, we aim to validate robust molecular markers linked to disease progression and survival. We performed multiple hypothesis testing-corrected analysis of variance (ANOVA) on the expression of individual genes across all CTCL samples and early stage (≤IIA) CTCL/MF patients. We used in silico immune cell-type deconvolution from gene expression data to estimate immune cell populations. Based on the analysis of all CTCL samples, we identified TOX, FYB, and CD52 as predictors of disease progression and poor survival. Among early stage (≤IIA) CTCL/MF patients, these 3 genes, along with CCR4, were valuable to predict disease progression. We validated these 4 genes in 3 independent, external Sézary Syndrome patient cohorts with RNA-Sequencing data. In silico immune cell-type deconvolution revealed that neutrophil infiltration in early stage MF conveyed a higher risk for disease progression. Also, NK cell infiltration in late stage MF/SS correlated with improved survival. TOX, FYB, CCR4 and CD52 are robust disease progression and decreased survival biomarkers in CTCL.

Healthcare resource utilization, costs of care, and treatment of mycosis fungoides cutaneous T-cell lymphoma patterns in a large managed care population: a retrospective US claims-based analysis

PURPOSE

To evaluate health care utilization, treatment patterns and costs among patients with mycosis fungoides-cutaneous T-cell lymphoma (MF-CTCL).

METHODS

This retrospective cohort study queried the HealthCore Integrated Research Database to identify patients ≥18 years with ≥2 diagnoses of MF-CTCL (ICD-9-CM code 202.1x, 202.2x) between 07 January 2006 and 07 January 2013. Index date was defined as first MF-CTCL diagnosis. Patients were continuously enrolled ≥6 months before and ≥12 months after index date. Severe MF-CTCL was identified via systemic therapy use postindex. Generalized linear model (GLM) was used to estimate the relationship between MF-CTCL severity and healthcare costs controlling for selected factors.

RESULTS

A total of 1981 MF-CTCL patients were evaluated: 493 (24.9%) severe and 1488 (75.1%) with mild to moderate disease. GLM analysis indicated severe MF-CTCL patients incurred higher all-cause healthcare total costs compared to patients with mild-to-moderate MF-CTCL (coefficient estimate: 4.19, p < .0001). About 51% of patients did not receive any MF-CTCL-specific treatment within 60 days after MF-CTCL diagnosis.

CONCLUSIONS

MF-CTCL severity was associated with greater healthcare resource utilization and costs. These findings suggest that about half of MF-CTCL patients do not receive MF-CTCL-specific treatment within 60 days following initial diagnosis. Future studies are needed to understand reasons for delayed treatment initiation.

Distribution and Clustering of Cutaneous T-Cell Lymphoma (CTCL) Cases in Canada During 1992 to 2010

BACKGROUND

Clustering of patients with cutaneous T-cell lymphoma (CTCL) was reported in several jurisdictions around the world. This rare cancer is known to affect spouses and in some cases multiple members of the same family. These combined results suggest the existence of external disease triggers/promoters. We recently conducted the first comprehensive analysis of CTCL incidence and mortality in Canada, which revealed case clustering in several regions.

OBJECTIVES

To extend our previous analysis on CTCL incidence across Canada and to provide all the collected data on CTCL patient incidence in Canada during the period of 1992 to 2010.

METHODS

Clinical parameters for patients with CTCL in Canada were analyzed using 2 independent population-based cancer registries: Canadian Cancer Registry and Le Registre Québécois du Cancer. The CTCL incidence rates were examined on different geographical levels, including provinces/territories, cities, and forward sortation areas.

RESULTS

Our findings further corroborate our earlier observations of higher CTCL incidence in Newfoundland and Labrador, maritime provinces (Nova Scotia and New Brunswick), and prairie provinces (Manitoba and Saskatchewan). Also, most cities with high CTCL incidence were located in these provinces. Extensive mapping of high-incidence postal codes supports case clustering in a number of communities that are located in the proximity of industrial centres and seaports.

CONCLUSIONS

Detailed analysis of CTCL incidence in Canada is critical to fully understand the burden of this disease in our country, to begin the search for a possible external trigger for this lymphoma, and to reform how health care resources are distributed throughout the country to better serve Canadian patients with CTCL.

Cutaneous T-cell Lymphoma

Cutaneous T-cell lymphomas comprise a heterogeneous group of diseases characterized by monoclonal proliferations of T lymphocytes primarily involving skin, modified skin appendages, and some mucosal sites. This article addresses the basic clinical, histologic, and immunohistochemical characteristics of this group of diseases, with additional attention to evolving literature on dermoscopy, reflectance confocal microscopy, flow cytometry, and molecular data that may increasingly be applied to diagnostic and therapeutic algorithms in these diseases. Select unusual phenotypes or diagnostic examples of classic phenotypes are demonstrated, and flags for consideration while making a pathologic diagnosis of cutaneous T-cell lymphoma are suggested.

TruSeq-Based Gene Expression Analysis of Formalin-Fixed Paraffin-Embedded (FFPE) Cutaneous T-Cell Lymphoma Samples: Subgroup Analysis Results and Elucidation of Biases from FFPE Sample Processing on the TruSeq Platform

Cutaneous T-cell lymphomas (CTCLs) are a heterogeneous group of malignancies with courses ranging from indolent to potentially lethal. We recently studied in a 157 patient cohort gene expression profiles generated by the TruSeq targeted RNA gene expression sequencing. We observed that the sequencing library quality and depth from formalin-fixed paraffin-embedded (FFPE) skin samples were significantly lower when biopsies were obtained prior to 2009. We also observed that the fresh CTCL samples clustered together, even though they included stage I–IV disease. In this study, we compared TruSeq gene expression patterns in older (≤2008) vs. more recent (≥2009) FFPE samples to determine whether these clustering analyses and earlier described differentially expressed gene findings are robust when analyzed based on the year of biopsy. We also explored biases found in FFPE samples when subjected to the TruSeq analysis of gene expression. Our results showed that ≤2008 and ≥2009 samples clustered equally well to the full data set and, importantly, both analyses produced nearly identical trends and findings. Specifically, both analyses enriched nearly identical DEGs when comparing benign vs. (1) stage I–IV and (2) stage IV (alone) CTCL samples. Results obtained using either ≤2008 or ≥2009 samples were strongly correlated. Furthermore, by using subgroup analyses, we were able to identify additional novel differentially expressed genes (DEGs), which did not reach statistical significance in the prior full data set analysis. Those included CTCL-upregulated BCL11A, SELL, IRF1, SMAD1, CASP1, BIRC5, and MAX and CTCL-downregulated MDM4, SERPINB3, and THBS4 genes. With respect to sample biases, no matter if we performed subgroup analyses or full data set analysis, fresh samples tightly clustered together. While principal component analysis revealed that fresh samples were spatially closer together, indicating some preprocessing batch effect, they remained in the proximity to other normal/benign and FFPE CTCL samples and were not clustering as outliers by themselves. Notably, this did not affect the determination of DEGs when analyzing ≥2009 samples (fresh and FFPE biopsies) vs. ≥2009 FFPE samples alone.

Oral and Cutaneous Lymphomas other than Mycosis Fungoides and Sézary Syndrome in a Mexican Cohort: Recategorization and Evaluation of International Geographical Disparities

Background:

Nonmycosis fungoides/Sézary syndrome (non-MF/SS) primary cutaneous lymphomas (PCL) are currently categorized under the 2005-World Health Organization/European Organization for Research and Treatment of Cancer (WHO-EORTC) classification for PCL. These differ in behavior from secondary cutaneous lymphomas (SCL) and to lymphomas limited to the oral cavity (primary oral lymphomas [POL]) both categorized under the 2016-WHO classification for lymphoid neoplasms.

Aims:

This study aims to report the first series of non-MF/SS PCL, SCL, and POL in a Mexican cohort, examine the applicability of current classification systems and compare our findings with those from foreign cohorts.

Materials and Methods:

Eighteen non-MF/SS PCL, four SCL, and two POL with available tissue for morphology and immunophenotypic assessment were reclassified according to the 2005-WHO/EORTC and 2016-WHO classifications.

Results:

Non-MF/SS PCLs were primarily of T-cell origin (61%) where CD30+ lymphoproliferative disorders predominated, followed by Epstein–Barr virus-induced lymphomas, and peripheral T-cell lymphomas, not otherwise specified. Primary cutaneous B-cell lymphomas (BCL) were primarily of follicle center cell origin followed by postgerminal lymphomas of the diffuse large BCL variety.

Conclusions:

Most non-MF/SS PCL, SCL, and POL can be adequately categorized according to the 2005-WHO/EORTC and 2016-WHO classification systems, even when dealing with clinically atypical cases. The relative frequencies in our cohort hold closer similarities to Asian registries than from those of Europe/USA, supporting the concept of individual and/or racial susceptibility, and the notion of geographical variances in the rate of lymphomas. In particular, such disparity may arise from viral-induced lymphomas which might show partial geographical restriction.

Malignant inflammation in cutaneous T-cell lymphoma-a hostile takeover

Cutaneous T-cell lymphomas (CTCL) are characterized by the presence of chronically inflamed skin lesions containing malignant T cells. Early disease presents as limited skin patches or plaques and exhibits an indolent behavior. For many patients, the disease never progresses beyond this stage, but in approximately one third of patients, the disease becomes progressive, and the skin lesions start to expand and evolve. Eventually, overt tumors develop and the malignant T cells may disseminate to the blood, lymph nodes, bone marrow, and visceral organs, often with a fatal outcome. The transition from early indolent to progressive and advanced disease is accompanied by a significant shift in the nature of the tumor-associated inflammation. This shift does not appear to be an epiphenomenon but rather a critical step in disease progression. Emerging evidence supports that the malignant T cells take control of the inflammatory environment, suppressing cellular immunity and anti-tumor responses while promoting a chronic inflammatory milieu that fuels their own expansion. Here, we review the inflammatory changes associated with disease progression in CTCL and point to their wider relevance in other cancer contexts. We further define the term "malignant inflammation" as a pro-tumorigenic inflammatory environment orchestrated by the tumor cells and discuss some of the mechanisms driving the development of malignant inflammation in CTCL.

Investigating potential exogenous tumor initiating and promoting factors for Cutaneous T-Cell Lymphomas (CTCL), a rare skin malignancy

Most skin malignancies are caused by external and often preventable environmental agents. Multiple reports demonstrated that cutaneous T-cell lymphomas (CTCL) can occur in married couples and cluster in families. Furthermore, recent studies document geographic clustering of this malignancy in Texas as well as in other areas of the United States. Multiple infectious, occupational, and medication causes have been proposed as triggers or promoters of this malignancy including hydrochlorothiazide diuretics, Staphylococcus aureus, dermatophytes, Mycobacterium leprae, Chlamydia pneumoniae, human T-Cell lymphotropic virus type 1 (HTLV1), Epstein-Barr virus (EBV), and herpes simplex virus (HSV). In this report, we review recent evidence evaluating the involvement of these agents in cancer initiation/progression. Most importantly, recent molecular experimental evidence documented for the first time that S. aureus can activate oncogenic STAT3 signaling in malignant T cells. Specifically, S. aureus Enterotoxin type A (SEA) was recently shown to trigger non-malignant infiltrating T cells to release IL-2 and other cytokines. These signals upon binging to their cognate receptors on malignant T cells are then able to activate STAT3 and STAT5 oncogenic signaling and promote cancer progression and IL-17 secretion. In light of these findings, it might be important for patients with exacerbation of their CTCL symptoms to maintain high index of suspicion and treat these individuals for S. aureus colonization and/or sepsis with topical and systemic antibiotics.

Cutaneous T-Cell Lymphoma: A Review with a Focus on Targeted Agents

Cutaneous T-cell lymphomas (CTCLs) are a heterogeneous group of extranodal lymphomas involving the skin. Diagnosis of the two main subtypes of CTCL-mycosis fungoides (MF) and Sézary syndrome (SS)-is based on the International Society for Cutaneous Lymphomas/European Organization for Research and Treatment of Cancer (ISCL/EORTC) classification system, which utilizes clinical, histopathological, molecular biologic, and immunopathologic features. Risk stratification, based on TNMB (tumor, node, metastasis, and blood) staging, provides prognostic information, with limited-stage disease conferring the longest median overall survival. Skin-directed therapies are preferred in the management of limited-stage disease, whereas advanced-stage disease requires systemic therapies. As the mechanisms of CTCL pathogenesis are increasingly understood, new monoclonal antibodies, checkpoint inhibitors, immunomodulatory agents, and small molecules are under investigation and may provide additional therapeutic options for those with advanced CTCL. This review examines the current landscape of targeted therapies in the treatment of CTCLs.

Staphylococcal enterotoxin A (SEA) stimulates STAT3 activation and IL-17 expression in cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is characterized by proliferation of malignant T cells in a chronic inflammatory environment. With disease progression, bacteria colonize the compromised skin barrier and half of CTCL patients die of infection rather than from direct organ involvement by the malignancy. Clinical data indicate that bacteria play a direct role in disease progression, but little is known about the mechanisms involved. Here, we demonstrate that bacterial isolates containing staphylococcal enterotoxin A (SEA) from the affected skin of CTCL patients, as well as recombinant SEA, stimulate activation of signal transducer and activator of transcription 3 (STAT3) and upregulation of interleukin (IL)-17 in immortalized and primary patient-derived malignant and nonmalignant T cells. Importantly, SEA induces STAT3 activation and IL-17 expression in malignant T cells when cocultured with nonmalignant T cells, indicating an indirect mode of action. In accordance, malignant T cells expressing an SEA-nonresponsive T-cell receptor variable region β chain are nonresponsive to SEA in monoculture but display strong STAT3 activation and IL-17 expression in cocultures with SEA-responsive nonmalignant T cells. The response is induced via IL-2 receptor common γ chain cytokines and a Janus kinase 3 (JAK3)-dependent pathway in malignant T cells, and blocked by tofacitinib, a clinical-grade JAK3 inhibitor. In conclusion, we demonstrate that SEA induces cell cross talk-dependent activation of STAT3 and expression of IL-17 in malignant T cells, suggesting a mechanism whereby SEA-producing bacteria promote activation of an established oncogenic pathway previously implicated in carcinogenesis.

Primary cutaneous lymphomas: A clinical and histological study of 99 cases in Isfahan, Iran

BACKGROUND

Primary cutaneous lymphomas (PCLs) represent a heterogeneous group of T- and B-cell lymphomas that present in the skin with no evidence of extracutaneous disease at the time of diagnosis. The aim of this study was to assess and report the epidemiological characteristics of PCLs in Isfahan, Isfahan Province, Iran - as a main province of Iran.

MATERIALS AND METHODS

A total of 99 patients were recruited over a recent 10-year period (2003-2013) with diagnosis of PCLs; the patients were classified according to the The World Health Organization/European Organization for Research and Treatment of Cancer (WHO-EORTC) criteria. Mean and standard deviations (SDs) were used to describe continuous data, numbers, and percentages for categorical data. Statistical significance was defined as P < 0.05.

RESULTS

The patients comprised 45 men and 54 women aged 5-80 years (median 36) at diagnosis. The male-to-female ratio was 1:1.2. Histological examination showed features of primary cutaneous B-cell lymphomas (PCBCLs) in four cases. The mean ± SD age in primary cutaneous T-cell lymphomas (PCTCLs) and PCBCLs was 37.9 ± 16.5 years and 39.7 ± 9.1 years, respectively (P = 0.72). The mean ± SD latent period between the time of diagnosis and initiation of skin lesions in men and women was 2.3 ± 4.1 years and 5.9 ± 10.1 years, respectively (P = 0.02). The most frequent subtypes were mycosis fungoides (MFs) (86.9%) followed by Sιzary syndrome (SS) (4%). Five patients died from PCL-related deaths.

CONCLUSION

The distinguishing epidemiologic characteristics of PCL in Iran are the absence of a male predominance and a lower age of diagnosis. The study highlights the ethnic or regional variations in the clinicoepidemiological characteristics of PCLs.