Brentuximab vedotin in the treatment of cutaneous T-cell lymphomas: Data from the Spanish Primary Cutaneous Lymphoma Registry.

BACKGROUND: Brentuximab vedotin (BV) has been approved for CD30-expressing cutaneous T-cell lymphoma (CTCL) after at least one previous systemic treatment. However, real clinical practice is still limited. OBJECTIVES: To evaluate the response and tolerance of BV in a cohort of patients with CTCL. METHODS: We analysed CTCL patients treated with BV from the Spanish Primary Cutaneous Lymphoma Registry (RELCP). RESULTS: Sixty-seven patients were included. There were 26 females and the mean age at diagnosis was 59 years. Forty-eight were mycosis fungoides (MF), 7 Sézary syndrome (SS) and 12 CD30+ lymphoproliferative disorders (CD30 LPD). Mean follow-up was 18 months. Thirty patients (45%) showed at least 10% of CD30+ cells among the total lymphocytic infiltrate. The median number of BV infusions received was 7. The overall response rate (ORR) was 67% (63% in MF, 71% in SS and 84% in CD30 LPD). Ten of 14 patients with folliculotropic MF (FMF) achieved complete or partial response (ORR 71%). The median time to response was 2.8 months. During follow-up, 36 cases (54%) experienced cutaneous relapse or progression. The median progression free survival (PFS) was 10.3 months. The most frequent adverse event was peripheral neuropathy (PN) (57%), in most patients (85%), grades 1 or 2. CONCLUSIONS: These results confirm the efficacy and safety of BV in patients with advanced-stage MF, and CD30 LPD. In addition, patients with FMF and SS also showed a favourable response. Our data suggest that BV retreatment is effective in a proportion of cases.

VEGFC Gene Expression Is Associated with Tumor Progression and Disease-Free Survival in Cutaneous Squamous Cell Carcinoma.

Cutaneous squamous cell carcinoma (CSCC) is one of the most common cancers in the skin. CSCC belongs to the non-melanoma skin cancers, and its incidence is increasing every year around the world. The principal routes of tumor progression are related to angiogenesis and lymphangiogenesis. In this study, we assess the gene expression of the relevant biomarkers of both routes in 49 formalin-fixed paraffin-embedded (FFPE) CSCC samples in an attempt to determine a molecular profile that correlates with the tumor progression and disease-free survival (DFS). The results were enhanced by a posttranscriptional analysis using an immunofluorescence assay. Overexpression of the vascular endothelial growth factor C (VEGFC) gene was found in patients with tumor progression (p = 0.022) and in patients with perineural invasion (p = 0.030). An increased expression of protein VEGFC in samples with tumor progression supported these results (p = 0.050). In addition, DFS curves showed differences (p = 0.027) for tumors with absent-low VEGFC expression versus those with high levels of VEGFC expression. No significant influence on DFS was detected for the remaining analyzed genes. VEGFC expression was found to be a risk factor in the disease progression (HR = 2.675; 95% CI: 1.089-6.570; p = 0.032). Our main results suggest that VEGFC gene expression is closely related to tumor progression, DFS, and the presence of perineural invasion.

Gene Expression Studies in Formalin-Fixed Paraffin-Embedded Samples of Cutaneous Cancer: The Need for Reference Genes.

Formalin-fixed paraffin-embedded (FFPE) tumour samples may provide crucial data regarding biomarkers for neoplasm progression. Analysis of gene expression is frequently used for this purpose. Therefore, mRNA expression needs to be normalized through comparison to reference genes. In this study, we establish which of the usually reported reference genes is the most reliable one in cutaneous malignant melanoma (MM) and cutaneous squamous cell carcinoma (CSCC). ACTB, TFRC, HPRT1 and TBP expression was quantified in 123 FFPE samples (74 MM and 49 CSCC biopsies) using qPCR. Expression stability was analysed by NormFinder and Bestkeeper softwares, and the direct comparison method between means and SD. The in-silico analysis with BestKeeper indicated that HPRT1 was more stable than ACTB and TFRC in MM (1.85 vs. 2.15) and CSCC tissues (2.09 vs. 2.33). The best option to NormFinder was ACTB gene (0.56) in MM and TFRC (0.26) in CSCC. The direct comparison method showed lower SD means of ACTB expression in MM (1.17) and TFRC expression in CSCC samples (1.00). When analysing the combination of two reference genes for improving stability, NormFinder indicated HPRT1 and ACTB to be the best for MM samples, and HPRT1 and TFRC genes for CSCC. In conclusion, HPRT1 and ACTB genes in combination are the most appropriate choice for normalization in gene expression studies in MM FFPE tissue, while the combination of HPRT1 and TFRC genes are the best option in analysing CSCC FFPE samples. These may be used consistently in forthcoming studies on gene expression in both tumours.

Primary cutaneous lymphomas in children: A prospective study from the Spanish Academy of Dermatology and Venereology (AEDV) Primary Cutaneous Lymphoma Registry.

BACKGROUND/OBJECTIVES: Primary cutaneous lymphomas are rare in pediatric patients. The clinical and histopathological manifestations may differ from those in adults. Due to their low frequency and the insidious clinical picture, the diagnosis is usually delayed. The Spanish Primary Cutaneous Lymphoma Registry was initiated in 2016 as a multicenter registry that would allow better insight into the epidemiological, clinical, histopathological, and treatment response characteristics of patients with primary cutaneous lymphomas. METHODS: We conducted a prospective observational cohort study of primary cutaneous lymphomas in pediatric patients participating in the Spanish Academy of Dermatology and Venereology (AEDV) Primary Cutaneous Lymphoma Registry. RESULTS: At the time of the analysis, 10 patients under 18 years of age out of 799 all-age cases (1.25%) had been included in the registry (7 males, 3 females). The mean age at diagnosis was 9.7 years (SD: 4.8). Seven (70%) had mycosis fungoides, 2 of them had the folliculotropic variant; and 3 (30%) had primary cutaneous marginal zone B-cell lymphoma. CONCLUSIONS: Primary cutaneous lymphomas are extremely rare in pediatric patients and usually have a good prognosis. Therefore, a high level of suspicion is necessary for the diagnosis. We suggest management by experienced physicians and follow-up into adulthood.

Does the new staging system proposed for mycosis fungoides and Sézary syndrome provide reliable agreement for T1 and T2 disease?

BACKGROUND: Patch or plaque stages in mycosis fungoides (MF) have different prognoses. The recent staging system proposed for MF discriminates between patches and plaques based upon clinical features. OBJECTIVE: To estimate interdermatologist agreement on the morphological evaluation of MF lesions. METHODS: Twenty-four patients with MF were enrolled. Two dermatologists evaluated every lesion face to face and independently with respect to the patch-plaque status. Cohen's κ was used to determine the rate of agreement. RESULTS: Agreement was 67% with respect to the patch or plaque status [95% confidence interval (CI) = 49-85%; p < 0.001]. Current systemic treatment (56%; p = 0.01) was associated with lower agreement. Younger age at diagnosis [odds ratio (OR) 1.03 (95% CI 1.02-1.05)], younger age at enrolment [OR 1.03 (95% CI 1.02-1.04)] and time on systemic treatment [OR 1.02 (95% CI 1.01-1.04)] were independent risk factors for disagreement (p < 0.001). CONCLUSION: The new system for MF staging carries a significant risk of disagreement regarding patch and plaque subsets.

MicroRNAs as prognostic markers in indolent primary cutaneous B-cell lymphoma.

Indolent primary cutaneous B-cell lymphoma is a group of malignant lymphomas comprising marginal zone B-cell lymphoma and centrofollicular B-cell lymphoma. Relapse rate of these tumors is close to 40%, and identifying those patients who are likely to progress remains a challenge. The aim of this study was to characterize the microRNA (miRNA) expression profile of a series of primary cutaneous B-cell lymphomas and correlate with histological and clinical findings. We studied a series of 68 patients with primary cutaneous B-cell lymphomas (30 cutaneous marginal-zone B-cell lymphomas and 38 primary cutaneous centrofollicular lymphomas). A set of 11 miRNAs associated with the differentiation stage of B cells was quantified by real-time PCR, using RNA extracted from formalin-fixed, paraffin-embedded tissue diagnostic samples. Relevant clinical variables were retrieved in a subset of 57 patients (28 cutaneous marginal zone B-cell lymphomas and 29 primary cutaneous centrofollicular lymphomas). miR-150 was upregulated in cutaneous marginal zone B-cell lymphomas relative to primary cutaneous centrofollicular lymphoma samples (false discovery rate <0.05). miR-155 and miR-150 expression levels were associated with progression-free survival in a univariate Cox regression analysis (P<0.1). After stratification by histological subtype, low-expression levels of miR-155 and miR-150 were both associated with shorter progression-free survival only in primary cutaneous marginal zone B-cell lymphomas cases (log-rank test, P<0.05). In summary, miRNA expression analysis can be used as a tool for diagnosis and outcome prognosis in indolent primary cutaneous B-cell lymphoma.

Expression of angiogenic and lymphangiogenic genes in primary cutaneous melanoma: relationship with angiolymphatic invasion and disease-free survival.

Melanoma is one of the most common cancers in the world. The main routes of tumor progression are related to angiogenesis and lymphangiogenesis. These routes can occur by local invasion, which is called angiolymphatic invasion (ALI). In this study, we assess gene expression of relevant biomarkers of angiogenesis and lymphangiogenesis in 80 FFPE melanoma samples to determine a molecular profile that correlates with ALI, tumor progression, and disease-free survival. The results were enhanced by a posttranscriptional analysis by an immunofluorescence assay. Three SNPs in the VEGFR-2 gene were genotyped in 237 malignant melanoma (MM) blood DNA samples by qPCR. A significant correlation was found for LYVE -1 and ALI, qualitative ( P  = 0.017) and quantitative ( P  = 0.005). An increased expression of protein LIVE-1 in ALI samples supported these results ( P  = 0.032). VEGFR2 was lower in patients who showed disease progression ( P  = 0.005) and protein VEGFR2 posttranscriptional expression decreased ( P  = 0.016). DFS curves showed differences ( P  = 0.023) for VEGFR2 expression detected versus the absence of VEGFR2 expression. No significant influence on DFS was detected for the remaining analyzed genes. Cox regression analysis suggested that VEGFR2 expression has a protective role (HR = 0.728; 95% CI = 0.552-0.962; P  = 0.025) on disease progression. No significant association was found between any of the studied SNPs of VEGFR2 and DFS or progression rate. Our main results suggest that LYVE-1 gene expression is closely related to ALI; the relationship with the development of metastases in MM deserves further studies. Low expression of VEGFR2 was associated with disease progression and the expression of VEGFR2 correlates with an increased DFS.

Melanocortin-1 receptor, skin cancer and phenotypic characteristics (M-SKIP) project: study design and methods for pooling results of genetic epidemiological studies.

BACKGROUND: For complex diseases like cancer, pooled-analysis of individual data represents a powerful tool to investigate the joint contribution of genetic, phenotypic and environmental factors to the development of a disease. Pooled-analysis of epidemiological studies has many advantages over meta-analysis, and preliminary results may be obtained faster and with lower costs than with prospective consortia. DESIGN AND METHODS: Based on our experience with the study design of the Melanocortin-1 receptor (MC1R) gene, SKin cancer and Phenotypic characteristics (M-SKIP) project, we describe the most important steps in planning and conducting a pooled-analysis of genetic epidemiological studies. We then present the statistical analysis plan that we are going to apply, giving particular attention to methods of analysis recently proposed to account for between-study heterogeneity and to explore the joint contribution of genetic, phenotypic and environmental factors in the development of a disease. Within the M-SKIP project, data on 10,959 skin cancer cases and 14,785 controls from 31 international investigators were checked for quality and recoded for standardization. We first proposed to fit the aggregated data with random-effects logistic regression models. However, for the M-SKIP project, a two-stage analysis will be preferred to overcome the problem regarding the availability of different study covariates. The joint contribution of MC1R variants and phenotypic characteristics to skin cancer development will be studied via logic regression modeling. DISCUSSION: Methodological guidelines to correctly design and conduct pooled-analyses are needed to facilitate application of such methods, thus providing a better summary of the actual findings on specific fields.

Activity and safety of topical pimecrolimus in patients with early stage mycosis fungoides (PimTo-MF): a single-arm, multicentre, phase 2 trial.

BACKGROUND: The calcineurin pathway is often activated in mycosis fungoides. We aimed to assess the activity and safety of topical pimecrolimus, a calcineurin inhibitor, in patients with early mycosis fungoides. METHODS: PimTo-MF was a single-arm, multicentre, phase 2 trial done at six medical centres in Spain. Patients (aged ≥18 years) had histologically confirmed early mycosis fungoides (stages IA-IIA) and an Eastern Cooperative Oncology Group performance status of 0-1. Key exclusion criteria included the use of concurrent treatments for mycosis fungoides, including sunbathing, topical or systemic corticosteroids, and other calcineurin inhibitors. Patients applied topical pimecrolimus 1% cream on their skin lesions twice daily for 16 weeks (1 g per 2% of body surface), with subsequent follow-up of 12 months. Dosage modifications were not allowed. To evaluate adherence to the treatment, patients were instructed to return all empty tubes to the hospital (as per drug accountability protocols). The primary endpoint was the overall response ratein the intention-to-treat population. PimTo-MF is registered with EudraCT, 2014-001377-14, and is complete. FINDINGS: Between March 1, 2015, and Sept 30, 2016, 39 patients were enrolled. All patients were assessable, with a median age of 51·5 years (IQR 45-62), and the population was predominantly male (24 male [62%], 15 female [38%]). Median follow-up after baseline was 5·7 years (IQR 5·7-6·2). 22 (56%) of 39 patients had an overall response (one complete response, 21 partial responses). Responses were observed across IA (14 [54%] of 26 patients) and IB (eight [73%] of 11 patients) clinical stages, but not IIA. Topical pimecrolimus was well tolerated and no patient required a dose reduction or discontinued treatment because of unacceptable drug-related toxicity. No patients were lost to follow-up or discontinued treatment. 13 (33%) of 39 patients reported adverse events; transitory mild burning or pruritus (grade 1) was the most common, seen in eight (21%) patients. In three (8%) of these patients, the burning or pruritus was considered related to treatment. No grade 4 or 5 adverse events were observed. INTERPRETATION: Pimecrolimus 1% cream seems active and safe in patients with early stage mycosis fungoides. Our findings should be taken with caution until long-term follow-up data are obtained that confirm the safety of this treatment. Further controlled clinical trials are warranted to confirm these results. FUNDING: Instituto de Salud Carlos III and the European Regional Development Fund. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

Cost of early-stage mycosis fungoides treatments in Spain.

AIM: To identify the most common therapeutic options for the treatment of early-stage mycosis fungoides in Spain, quantify their associated healthcare resource use and costs. METHODS: After reviewing the literature, a panel of 6 Spanish clinical dermatologists validated the treatments and healthcare resource use through a structured questionnaire. Individual responses were collected, analyzed and presented into a face-to-face meeting in order to reach a consensus. Cost categories considered were: drug acquisition and administration, photo/radiotherapy session and maintenance, clinical follow-up visits and laboratory tests. Costs were expressed in euros from 2018. The Spanish National Health System perspective was considered, taking into account direct health costs and time horizons of 1, 3 and 6 months. RESULTS: Costs for the skin-directed treatments (SDT) assessed at 1, 3 and 6 months, were: Topical carmustine [€6,593.36, €19,780.09 and €27,592.78]; Phototherapy with psoralens and ultraviolet A light (PUVA) [€1,098.68, €2,999.99 and €3,187.60]; Narrow-band ultraviolet B phototherapy [€1,657.47, €4,842.10 and €4,842.10]; Total skin electron beam therapy (TSEBT) [€6,796.45, €7,913.34 and €7,913.34]. Cost for topical corticosteroids, being considered an adjuvant option, were €17.16, €51.49 and €102.97. Costs for the assessed systemic treatments alone or in combination with SDT at 1, 3 and 6 months, were: Systemic retinoids [€2,026.03, €5,206.63 and €7,426.42]; Systemic retinoids + PUVA phototherapy [€3,066.50, €8,271.26 and €10,046.58]; Interferon alfa + PUVA phototherapy [€1,541.09, €5,167.57 and €6,404.55]. CONCLUSION: According to the Spanish clinical practice, phototherapies in monotherapy were the treatments with the lowest associated costs regardless of the time horizon considered. TSEBT turned out as the treatment with the highest associated costs when considering 1 month. However, while considering 3 and 6 months the treatment with the highest associated costs was topical carmustine. The results of this analysis may provide critical information to measure the disease burden, to detect unmet medical needs and to advocate towards better treatments for this rare disease.

MC1R variants in childhood and adolescent melanoma: a retrospective pooled analysis of a multicentre cohort.

BACKGROUND: Germline variants in the melanocortin 1 receptor gene (MC1R) might increase the risk of childhood and adolescent melanoma, but a clear conclusion is challenging because of the low number of studies and cases. We assessed the association of MC1R variants with childhood and adolescent melanoma in a large study comparing the prevalence of MC1R variants in child or adolescent patients with melanoma to that in adult patients with melanoma and in healthy adult controls. METHODS: In this retrospective pooled analysis, we used the M-SKIP Project, the Italian Melanoma Intergroup, and other European groups (with participants from Australia, Canada, France, Greece, Italy, the Netherlands, Serbia, Spain, Sweden, Turkey, and the USA) to assemble an international multicentre cohort. We gathered phenotypic and genetic data from children or adolescents diagnosed with sporadic single-primary cutaneous melanoma at age 20 years or younger, adult patients with sporadic single-primary cutaneous melanoma diagnosed at age 35 years or older, and healthy adult individuals as controls. We calculated odds ratios (ORs) for childhood and adolescent melanoma associated with MC1R variants by multivariable logistic regression. Subgroup analysis was done for children aged 18 or younger and 14 years or younger. FINDINGS: We analysed data from 233 young patients, 932 adult patients, and 932 healthy adult controls. Children and adolescents had higher odds of carrying MC1R r variants than did adult patients (OR 1·54, 95% CI 1·02-2·33), including when analysis was restricted to patients aged 18 years or younger (1·80, 1·06-3·07). All investigated variants, except Arg160Trp, tended, to varying degrees, to have higher frequencies in young patients than in adult patients, with significantly higher frequencies found for Val60Leu (OR 1·60, 95% CI 1·05-2·44; p=0·04) and Asp294His (2·15, 1·05-4·40; p=0·04). Compared with those of healthy controls, young patients with melanoma had significantly higher frequencies of any MC1R variants. INTERPRETATION: Our pooled analysis of MC1R genetic data of young patients with melanoma showed that MC1R r variants were more prevalent in childhood and adolescent melanoma than in adult melanoma, especially in patients aged 18 years or younger. Our findings support the role of MC1R in childhood and adolescent melanoma susceptibility, with a potential clinical relevance for developing early melanoma detection and preventive strategies. FUNDING: SPD-Pilot/Project-Award-2015; AIRC-MFAG-11831.

Association of APOA5 and APOC3 Genetic Polymorphisms With Severity of Hypertriglyceridemia in Patients With Cutaneous T-Cell Lymphoma Treated With Bexarotene.

Importance: Hypertriglyceridemia is the most frequent and limiting adverse effect of bexarotene therapy in cutaneous T-cell lymphoma (CTCL). Despite standard prophylactic measures, there is a wide variability in the severity of this complication, which could be associated with both genetic and environmental factors. Objectives: To analyze the association between genetic polymorphisms of apolipoprotein genes APOA5, APOC3, and APOE and the severity of hypertriglyceridemia during bexarotene therapy and to optimize patient selection for bexarotene therapy based on adverse effect profile. Design, Setting, and Participants: This case series study was conducted in 12 university referral hospitals in Spain from September 17, 2014, to February 6, 2015. One hundred twenty-five patients with a confirmed diagnosis of CTCL who had received bexarotene therapy for at least 3 months were enrolled. Nine patients were excluded owing to missing analytic triglyceride level data, leaving a study group of 116 patients. Data on demographic and cardiovascular risk factor were collected, and a complete blood analysis, including lipid profile and genetic analysis from a saliva sample, was performed. Main Outcomes and Measures: Primary outcomes were the maximal triglyceride levels reported in association with the minor alleles of the polymorphisms studied. Results: Among 116 patients, the mean (SD) age was 61.2 (14.7) years, 69 (59.5%) were men, and 85 (73.2%) had mycosis fungoides, the most prevalent form of CTCL. During bexarotene therapy, 96 patients (82.7%) experienced hypertriglyceridemia, which was severe or extreme in 8 of these patients (8.3%). Patients who carried minor alleles of the polymorphisms did not show significant differences in baseline triglyceride concentrations. After bexarotene treatment, carriers of at least 1 of the 2 minor alleles of APOA5 c.-1131T>C and APOC3 c.*40C>G showed lower levels of triglycerides than noncarriers (mean [SD], 241.59 [169.91] vs 330.97 [169.03] mg/dL, respectively; P = .02). Conclusions and Relevance: These results indicate that the screening of APOA5 and APOC3 genotypes may be useful to estimate changes in triglyceride concentrations during bexarotene treatment in patients with CTCL and also to identify the best candidates for bexarotene therapy based on the expected adverse effect profile.

Melanoma: diagnosis, staging, and treatment. Consensus group recommendations.

The incidence of malignant melanoma is increasing worldwide. In Spain, its incidence is increasing faster than any other cancer type, with a 5-year survival rate of about 85%. The impact and characteristics of malignant melanoma in the Spanish population can be ascertained from the national melanoma registry of the Academia Española de Dermatología y Venereología. This review presents consensus group recommendations for the diagnosis, staging and treatment of malignant melanoma in Spain. Incidence and mortality are discussed, as well as evaluation of various prevention and treatment strategies. Prognostic factors, such as BRAF and C-KIT mutations, which are expected to become routine staging procedures over the next few years, are outlined, especially in relation to treatment options. The use of recently approved targeted agents such as ipilimumab, a cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) inhibitor, and vemurafenib, a BRAF inhibitor, in metastatic disease are also discussed.

Treatment of stage Ia and Ib mycosis fungoides with psoralen UVA monotherapy: an observational study in tertiary hospitals in the Canary Islands.

BACKGROUND: Mycosis fungoides (MF) is the most common form of primary cutaneous T cell lymphoma. Psoralen combined with ultraviolet A (PUVA) is a first-line treatment for early-stage disease. OBJECTIVES: This study was conducted to assess the clinical effectiveness of and tolerance to PUVA monotherapy in MF. METHODS: We retrospectively reviewed the files of patients who received PUVA for stage I disease. The study included 31 patients, of whom 32% presented with stage Ia and 67% with stage Ib disease, and 68% presented with patch and 32% with plaque disease. All patients received treatment three times per week. RESULTS: Complete response (CR) was achieved in 71% of patients. The median cumulative dose of UVA at CR was 211.7 J/cm(2) . There was a significant difference in median cumulative dose at CR between patients with plaque and patch disease, respectively, but not between patients with stage Ia and Ib disease. Median disease-free survival (DFS) was 230 weeks. Patients with patch disease achieved longer DFS than those with plaque disease (P = 0.004), although DFS was similar in stage Ia and Ib patients. Of the patients who received maintenance therapy, 58% relapsed. Univariate analysis showed patch disease to be a predictive factor for CR, but no predictors of relapse were identified. A total of 71% of patients developed clinical adverse reactions. CONCLUSIONS: Psoralen with UVA is a safe and effective treatment for early-stage MF. Patch disease responds more favorably than plaque disease and is associated with a longer period of DFS. Maintenance treatment does not appear to reduce recurrence. Current evidence suggests that the proposed revision to the classification of MF, which takes into account the extent and type of disease, more accurately predicts response to PUVA.

MC1R gene variants and sporadic malignant melanoma susceptibility in the Canary Islands population.

Several MC1R variants are associated with increased risk of malignant melanoma (MM) in a variety of populations. We aim to examine the influence of the MC1R variants (RHC: D84E, R151C, R160W; NRHC: V60L, R163Q and the synonymous polymorphism T314T) on the MM risk in a population from the Canary Islands. Overall, 1,046 Caucasian individuals were included in the study. A thousand of them were genotyped for MC1R variants: 509 were sporadic MM patients and 491 were healthy control subjects from general population. The analysis was adjusted for age, sex, hair colour, eye colour, skin phototype and ancestry. We found that carriers of the R151C and R163Q variants were at an increased risk for melanoma OR 2.76 (1.59-4.78) and OR 5.62 (2.54-12.42), respectively. The risk of carrying RHC variants was 3.04 (1.90-4.86). Current study confirms the increased MM risk for R151C carriers. It also supports the association between R163Q variant and MM risk in the population on the Canary Islands, as opposed to reported on northern populations. These results highlight the importance of the sample population selection in this kind of studies.