Genetically predicted TWEAK mediates the association between lipidome and Keratinocyte Carcinomas.

BACKGROUND: Reports suggest that lipid profiles may be linked to the likelihood of developing skin cancer, yet the exact causal relationship is still unknown. OBJECTIVE: This study aimed to examine the connection between lipidome and skin cancers, as well as investigate any possible mediators. METHODS: A two-sample Mendelian randomization (MR) analysis was conducted on 179 lipidomes and each skin cancer based on a genome-wide association study (GWAS), including melanoma, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC). Then, Bayesian weighted MR was performed to verify the analysis results of two-sample MR. Moreover, a two-step MR was employed to investigate the impact of TNF-like weak inducer of apoptosis (TWEAK)-mediated lipidome on skin cancer rates. RESULTS: MR analysis identified higher genetically predicted phosphatidylcholine (PC) (17:0_18:2) could reduce the risk of skin tumors, including BCC (OR = 0.9149, 95% CI: 0.8667-0.9658), SCC (OR = 0.9343, 95% CI: 0.9087-0.9606) and melanoma (OR = 0.9982, 95% CI: 0.9966-0.9997). The proportion of PC (17:0_18:2) predicted by TWEAK-mediated genetic prediction was 6.6 % in BCC and 7.6% in SCC. The causal relationship between PC (17:0_18:2) and melanoma was not mediated by TWEAK. CONCLUSION: This study identified a negative causal relationship between PC (17:0_18:2) and keratinocyte carcinomas, a small part of which was mediated by TWEAK, and most of the remaining mediating factors are still unclear. Further research on other risk factors is needed in the future.

Molecular Profiling and the Interaction of Somatic Mutations with Transcriptomic Profiles in Non-Melanoma Skin Cancer (NMSC) in a Population Exposed to Arsenic.

Exposure to inorganic arsenic (As) is recognized as a risk factor for non-melanoma skin cancer (NMSC). We followed up with 7000 adults for 6 years who were exposed to As. During follow-up, 2.2% of the males and 1.3% of the females developed basal cell carcinoma (BCC), while 0.4% of the male and 0.2% of the female participants developed squamous cell carcinoma (SCC). Using a panel of more than 400 cancer-related genes, we detected somatic mutations (SMs) in the first 32 NMSC samples (BCC = 26 and SCC = 6) by comparing paired (tissue-blood) samples from the same individual and then comparing them to the SM in healthy skin tissue from 16 participants. We identified (a) a list of NMSC-associated SMs, (b) SMs present in both NMSC and healthy skin, and (c) SMs found only in healthy skin. We also demonstrate that the presence of non-synonymous SMs in the top mutated genes (like PTCH1, NOTCH1, SYNE1, PKHD1 in BCC and TP53 in SCC) significantly affects the magnitude of differential expressions of major genes and gene pathways (basal cell carcinoma pathways, NOTCH signaling, IL-17 signaling, p53 signaling, Wnt signaling pathway). These findings may help select groups of patients for targeted therapy, like hedgehog signaling inhibitors, IL17 inhibitors, etc., in the future.

Genetic causal relationship between gut microbiota and basal cell carcinoma: A two-sample mendelian randomization study.

OBJECTIVE: Research has previously established connections between the intestinal microbiome and the progression of some cancers. However, there is a noticeable gap in the literature in regard to using Mendelian randomisation (MR) to delve into potential causal relationships between the gut microbiota (GM) and basal cell carcinoma (BCC). Therefore, the purpose of our study was to use MR to explore the causal relationship between four kinds of GM (Bacteroides, Streptococcus, Proteobacteria and Lachnospiraceae) and BCC. METHODS: We used genome-wide association study (GWAS) data and MR to explore the causal relationship between four kinds of GM and BCC. This study primarily employed the random effect inverse variance weighted (IVW) model for analysis, as complemented by additional methods including the simple mode, weighted median, weighted mode and MR‒Egger methods. We used heterogeneity and horizontal multiplicity to judge the reliability of each analysis. MR-PRESSO was mainly used to detect and correct outliers. RESULTS: The random-effects IVW results showed that Bacteroides (OR = 0.936, 95% CI = 0.787-1.113, p = 0.455), Streptococcus (OR = 0.974, 95% CI = 0.875-1.083, p = 0.629), Proteobacteria (OR = 1.113, 95% CI = 0.977-1.267, p = 0.106) and Lachnospiraceae (OR = 1.027, 95% CI = 0.899-1.173, p = 0.688) had no genetic causal relationship with BCC. All analyses revealed no horizontal pleiotropy, heterogeneity or outliers. CONCLUSION: We found that Bacteroides, Streptococcus, Proteobacteria and Lachnospiraceae do not increase the incidence of BCC at the genetic level, which provides new insight for the study of GM and BCC.

From bedside to genetic analysis: New insights into pathophysiology of melanoma, basal cell carcinoma, and other cancers.

OBJECTIVE: Patients with myotonic muscular dystrophy (MMD) were observed to have numerous basal cell carcinoma (BCC) and abnormal dysplastic nevi (DN) on non-sun exposed skin. Simultaneously a large study published in the Journal of American Medical Association (JAMA) illustrated that patients with MMD have "overall" an increased risk for cancer development. Based on these findings, this author in 2010 postulated that dysregulation of RNA binding proteins (RBP), responsible for clinical manifestations of MMD, is also responsible for the development of BCC and melanoma. METHODS: To report new research elucidating the etiology of melanoma, BCC, MMD-induced cancers, and potentially other environmentally induced malignancies. RESULTS: Dysregulation of RBP induces aberrant mRNA splicing; recent data indicates that abnormal mRNA splicing not just plays a key role in the pathogenesis of melanoma but is a hallmark of essentially all human malignancies. CONCLUSION: The author's hypothesis is that ultraviolet (UV) radiation induces DNA damage in intronic regions of a variety of genes. Furthermore, these UV-induced abnormal DNA dimers, repeats and mutations interfere with normal mRNA splicing thus producing abnormal proteins. These abnormal proteins in turn activate oncogenic pathways such as hedgehog, MAP kinase, and WNT.

Causal relationship between genetically determined plasma metabolites and skin cancer: a two-sample Mendelian randomization study.

We aimed to unveil the underlying pathogenic mechanisms of skin cancer in relation to metabolic factors and pathway mechanisms. This study utilized the TwoSample Mendelian randomization (MR) method to investigate the causal relationship between 1400 plasma metabolites and skin cancer. The primary method employed was the inverse variance weighting (IVW). Through IVW analysis, we found 105 plasma metabolites associated with Basal Cell Carcinoma (BCC), with the highest association observed for Prolylglycine levels (OR [95% CI]: 1.1902 [1.0274, 1.3788]). For Malignant Melanoma of Skin (MSS), 68 plasma metabolites were linked, with the highest causal relationship seen for 3-Hydroxybutyrate levels (OR [95% CI]: 1.0030 [1.0013, 1.0048]). Regarding actinic keratosis (AK), and the highest association observed for Hexadecadienoate (16:2n6) levels (OR [95% CI]: 1.3302 [1.0333, 1.7125]). Glycerol to palmitoylcarnitine (16: n6) levels (OR [95% CI]: 1.3302 [1.0333, 1.125]) were found to be significant for BCC and AK. Palmitoylcarnitine (C16) had the most positive causal effect for BCC (OR [95% CI]: 1.1777 [1.0493, 1.3218]), while 5-hydroxy-2-methylpyridine sulfate levels had the highest effect for AK (OR [95% CI]: 1.1788 [1.0295, 1.3498]). And 4-guanidinobutanoate levels had the largest positive causal effect (OR [95% CI]: 1.0857 [1.0417, 1.1317]) for BCC, and X-11880 levels for MSS (OR [95% CI]: 1.0013 [1.0000, 1.0025]). The study revealed a positive association between hereditary Glycerol to palmitoylcarnitine (C16) and 5-hydroxy-2-methylpyridine sulfate levels with the risk of developing BCC and AK. Additionally, 4-guanidinobutanoate levels and X 11880 levels were found to be positively associated with the risk of BCC and MMS.

Novel insights into rosacea's role in cancer risk: A Mendelian randomization approach.

BACKGROUND: Chronic inflammation has been shown to promote cancer progression. Rosacea is indeed a long-term inflammatory skin condition and had been reported to link with increased risk for several types of malignancies, but evidence for causality is lacking. OBJECTIVES: To systematically estimate the causal relationship between rosacea and several types of cancer, including cutaneous malignant melanoma (CMM), cutaneous squamous cell carcinoma (cSCC), basal cell carcinoma (BCC), actinic keratosis (AK), thyroid cancer, breast cancer, glioma and hepatic cancer, as well as explore the potential underlying pathogenesis. METHODS: We conducted a bidirectional two-sample Mendelian randomization study to probe the potential causal relationships between rosacea and several types of cancer. Instrumental variables were established using genome-wide significant single nucleotide polymorphisms associated with rosacea and cancers. The assessment of causality was carried out through multiple methods, and the robustness of the results was evaluated via sensitivity analyses. RESULTS: There was no significant indication of causal effects of rosacea on CMM (pivw = 0.71), cSCC (pivw = 0.45), BCC (pivw = 0.90), AK (pivw = 0.73), thyroid cancer (pivw = 0.59), glioma (pivw = 0.15), and hepatic cancer (pivw = 0.07), but the genetic risk of rosacea was associated with an increased susceptibility to human epidermal growth factor receptor (HER)-negative malignant neoplasm of breast (odds ratio [OR], 1.10; 95% confidence interval [CI], 1.02-1.18; pivw = 0.01). TANK (TRAF family member associated nuclear factor kappa B (NFKB) activator) was identified as a common protective gene for both rosacea (OR, 0.90; 95% CI, 0.82-0.99; pivw = 0.048) and HER-negative malignant neoplasm of the breast (OR, 0.86; 95% CI, 0.75-0.98; pivw = 0.032), which was primarily enriched in the negative regulation of NF-κB signal transduction and may contribute to the genetic links between rosacea and this subtype of breast cancer. CONCLUSIONS: Our findings provide suggestive evidence for causal links between rosacea and HER-negative malignant neoplasm of the breast risk.

Investigation of Genetic Association Between a High Activity Variant of Cathepsin G and Risk for Basal Cell Carcinoma.

BACKGROUND/AIM: Cathepsin G (CTSG) has been identified as an inhibitor of breast, bladder, and colorectal cancers. The G allele of the N125S (A/G, rs45567233) functional polymorphism of the CTSG gene confers increased serum CTSG activity and has been associated with cardiovascular and neurovascular diseases. This study examined the possible correlation between the pathogenesis of basal cell carcinoma (BCC) and the functional polymorphism CTSG N125S. PATIENTS AND METHODS: A total of 197 DNA samples were examined, comprising 98 BCC patients and 99 control samples of Greek origin. The CTSG N125S polymorphism was molecularly genotyped using PCR amplification, followed by enzyme digestion, and agarose gel electrophoresis of the amplified DNA fragments. RESULTS: There was no statistically significant difference in the genotypic and allelic frequencies between the patient and the control groups. CONCLUSION: There is no association between the CTSG N125S polymorphism and pathogenesis of BCC.

Genetic predisposition to childhood obesity does not influence the risk of developing skin cancer in adulthood.

The relationship between body mass index (BMI) and melanoma and other skin cancers remains unclear. The objective of this study was to employ the Mendelian randomization (MR) approach to evaluate the effects of genetically predicted childhood adiposity on the risk of developing skin cancer later in life. Two-sample MR analyses were conducted using summary data from genome-wide association study (GWAS) meta-analyses of childhood BMI, melanoma, cutaneous squamous cell carcinoma (cSCC), and basal cell carcinoma (BCC). We used the inverse-variance-weighted (IVW) methods to obtain a pooled estimate across all genetic variants for childhood BMI. We performed multiple sensitivity analyses to evaluate the potential influence of various assumptions on our findings. We found no evidence that genetically predicted childhood BMI was associated with risks of developing melanoma, cSCC, or BCC in adulthood (OR, 95% CI: melanoma: 1.02 (0.93-1.13), cSCC 0.94 (0.79-1.11), BCC 0.97 (0.84-1.12)). Our findings do not support the conclusions from observational studies that childhood BMI is associated with increased risks of melanoma, cSCC, or BCC in adulthood. Intervening on childhood adiposity will not reduce the risk of common skin cancers later in life.

Laser-assisted topical delivery of vismodegib reduces hedgehog gene expression in human basal cell carcinomas in vivo.

BACKGROUND: Systemically delivered hedgehog inhibitors including vismodegib and sonidegib are widely used to treat basal cell carcinomas (BCCs). Ablative fractional laser (AFL)-assisted topical delivery of vismodegib has been demonstrated in preclinical studies. The aim of this explorative clinical study was to evaluate intratumoral vismodegib concentrations and effect on hedgehog pathway gene expression following AFL-assisted topical vismodegib delivery to BCCs. METHODS: In an open-label clinical trial, 16 nodular BCCs (in n = 9 patients) received one application of CO2 -AFL (40 mJ/microbeam, 10% density) followed by topical vismodegib emulsion. After 3-4 days, vismodegib concentrations in tumor biopsies (n = 15) and plasma were analyzed and compared with samples from patients receiving oral treatment (n = 3). GLI1, GLI2, PTCH1, and PTCH2 expression was determined by quantitative polymerase chain reaction (n = 7) and GLI1 additionally by in situ hybridization (n = 3). RESULTS: Following AFL-assisted topical administration, vismodegib was detected in 14/15 BCCs and reached a median concentration of 6.2 µmol/L, which compared to concentrations in BCC tissue from patients receiving oral vismodegib (9.5 µmol/L, n = 3, p = 0.8588). Topical vismodegib reduced intratumoral GLI1 expression by 51%, GLI2 by 55%, PTCH1 and PTCH2 each by 73% (p ≤ 0.0304) regardless of vismodegib concentrations (p ≥ 0.3164). In situ hybridization demonstrated that GLI1 expression was restricted to tumor tissue and downregulated in response to vismodegib exposure. CONCLUSION: A single AFL-assisted topical application of vismodegib resulted in clinically relevant intratumoral drug concentrations and significant reductions in hedgehog pathway gene expressions.

Ablative fractional laser treatment reduces hedgehog pathway gene expression in murine basal cell carcinomas.

This study aimed to investigate the impact of ablative fractional laser (AFL) on hedgehog pathway gene expression in murine microscopic basal cell carcinomas (BCCs) and compare these results to the effect of topical treatment with vismodegib, an FDA-approved hedgehog inhibitor. In 25 mice, 1 cm2 skin test sites (n = 44) containing microscopic BCCs were exposed to one of three interventions: a single CO2 AFL treatment (1 pulse, 40 mJ/microbeam, wavelength 10.6 µm, 5% density, pulse rate 250 Hz, n = 12), eight topical vismodegib treatments (3.8 mg/mL, n = 8), or combination of AFL and vismodegib treatments (n = 9). Untreated controls were included for comparison (n = 15). After 4 days, skin samples were analyzed for hedgehog gene expression (Gli1, Gli2, and Ptch1) by qPCR and vismodegib concentrations by liquid chromatography mass spectrometry (data analyzed with two-tailed t-tests and linear regression). A single treatment with AFL monotherapy significantly reduced hedgehog gene expression compared to untreated controls (Gli1 72.4% reduction, p = 0.003; Gli2 55.2%, p = 0.010; Ptch1 70.9%, p < 0.001). Vismodegib treatment also reduced hedgehog gene expression (Gli1 91.6%; Gli2 83.3%; Ptch1 83.0%), significantly surpassing AFL monotherapy for two out of three genes (Gli1, p = 0.017; Gli2, p = 0.007; Ptch1, p = 0.15). AFL and vismodegib combination mirrored the effects of vismodegib monotherapy (Gli1, p = 0.424; Gli2, p = 0.289; Ptch1, p = 0.593), possibly due to comparable cutaneous vismodegib concentrations (mean ± SD, vismodegib monotherapy 850 ± 475 µmol/L; combination 1036 ± 824 µmol/L; p = 0.573). In conclusion, a single AFL treatment significantly reduced hedgehog gene expression in murine BCCs mimicking the effects of eight topical applications of vismodegib. Further studies are needed to assess whether AFL can be utilized for BCC treatment, either as monotherapy or in combination with other drugs.

Causal relationship between the gut microbiome and basal cell carcinoma, melanoma skin cancer, ease of skin tanning: evidence from three two-sample mendelian randomisation studies.

Objectives: The present study used publicly available genome-wide association study (GWAS) summary data to perform three two-sample Mendelian randomization (MR) studies, aiming to examine the causal links between gut microbiome and BCC, melanoma skin cancer, ease of skin tanning. Methods: SNPs associated with exposures to basal cell carcinoma, melanoma skin cancer and ease of skin tanning from the genome-wide association study data of UK Biobank and MRC-IEU (MRC Integrative Epidemiology Unit), and the meta-analysis data from Biobank and MRC-IEU were used as instrumental variables (IVs). The casual estimates were assessed with a two-sample Mendelian randomisation test using the inverse-variance-weighted (IVW) method, Wald ratio, MR-Egger method, maximum likelihood, weighted median, simple mode, and weighted mode. Results: After the application of MR analysis, diffirent effects of multiple groups of gut microbiota was observed for BCC, melanoma skin cancer and ease of skin tanning. The relationships between the gut microbiome and BCC, melanoma skin cancer, ease of skin tanning were supported by a suite of sensitivity analyses, with no statistical evidence of instrument heterogeneity or horizontal pleiotropy. Further investigation is required to explore the relationship between between the gut microbiome and BCC, melanoma skin cancer, ease of skin tanning. Conclusion: Our study initially identified potential causal roles between the gut microbiome and BCC, melanoma skin cancer, ease of skin tanning, and highlighted the role of gut microbiome in the progression of basal cell carcinoma, melanoma skin cancer, ease of skin tanning.

Multi-ancestry genome-wide meta-analysis identifies novel basal cell carcinoma loci and shared genetic effects with squamous cell carcinoma.

Basal cell carcinoma (BCC) is one of the most common malignancies worldwide, yet its genetic determinants are incompletely defined. We perform a European ancestry genome-wide association (GWA) meta-analysis and a Hispanic/Latino ancestry GWA meta-analysis and meta-analyze both in a multi-ancestry GWAS meta-analysis of BCC, totaling 50,531 BCC cases and 762,234 controls from four cohorts (GERA, Mass-General Brigham Biobank, UK Biobank, and 23andMe research cohort). Here we identify 122 BCC-associated loci, of which 36 were novel, and subsequently fine-mapped these associations. We also identify an association of the well-known pigment gene SLC45A2 as well as associations at RCC2 and CLPTM1L with BCC in Hispanic/Latinos. We examine these BCC loci for association with cutaneous squamous cell carcinoma (cSCC) in 16,407 SCC cases and 762,486 controls of European ancestry, and 33 SNPs show evidence of association. Our study findings provide important insights into the genetic basis of BCC and cSCC susceptibility.

PTCH1 gene variants rs357564, rs2236405, rs2297086 and rs41313327, mRNA and tissue expression in basal cell carcinoma patients from Western Mexico.

BACKGROUND: Basal cell carcinoma (BCC) represents about 80% of all cases of skin cancer. The PTCH1 is a transmembrane protein of the Sonic Hedgehog signaling pathway that regulates cell proliferation. Genetic variants in PTCH1 gene have been previously described in association with BCC development. In addition, PTCH1 mRNA and protein expression analysis are also significant to understand its role in skin cancer physiopathology. METHODS: An analytical cross-sectional study was performed, and a total of 250 BCC patients and 290 subjects from the control group (CG) were included, all born in western Mexico. The genotypes and relative expression of the mRNA were determined by TaqMan® assay. The protein expression was investigated in 70 BCC paraffin-embedded samples with PTCH1 antibodies. Semi-quantitative analysis was performed to determine the expression level in the immunostained cells. RESULTS: We did not find evidence of an association between PTCH1 rs357564, rs2297086, rs2236405, and rs41313327 genetic variants and susceptibility to BCC. Likewise, no statistically significant differences were found in the comparison of the mRNA level expression between BCC and CG (p > 0.05). The PTCH1 protein showed a low expression in 6 of the analyzed samples and moderate expression in 1 sample. No association was found between genetic variants, protein expression, and demographic-clinical characteristics (p > 0.05). CONCLUSION: The studied PTCH1 variants may not be associated with BCC development in the Western Mexico population. The PTCH1 mRNA levels were lower in patients with BCC compared to the control group, but its protein was underexpressed in the tissue samples.

The causal effects of atopic dermatitis on the risk of skin cancers: A two-sample Mendelian randomization study.

BACKGROUND: Observational and epidemiological studies show conflicting results on the relationship between atopic dermatitis and skin cancer. Additionally, observational studies are susceptible to the reverse causation and confounders, thus, may not interpret true causal relationships. The causal effects of atopic dermatitis on the risk of skin cancers remains unclear. OBJECTIVES: To investigate the causal relationship between atopic dermatitis and skin cancer including cutaneous malignant melanoma, cutaneous squamous cell carcinoma, basal cell carcinoma and actinic keratosis. METHODS: We performed a two-sample Mendelian randomization analysis based on summary datasets of public genome-wide association studies of European ancestry. The inverse variance-weighted approach was applied as the main analysis. MR-Egger and weighted median methods were used to complement the inverse variance-weighted results. A series of sensitivity analyses were used to ensure the robustness of the causality estimates. RESULTS: Inverse variance-weighted method showed that genetically predicted dermatitis patients were significantly associated with an increased incidence of basal cell carcinoma (OR, 1.20; 95% CI, 1.10-1.31; p = 4.07E-05) and cutaneous squamous cell carcinoma (OR, 1.14; 95% CI, 1.10-1.19; p = 1.05E-11). However, we did not find a significant causality for atopic dermatitis on melanoma neither did we find actinic keratosis. Subsequent sensitive analyses supported these results. CONCLUSIONS: Our study identified the causality between atopic dermatitis basal cell carcinoma and squamous cell carcinoma. Accordingly, regular skin cancer screening is recommended for patients with atopic dermatitis.

Acquisition of Drug Resistance in Basal Cell Nevus Syndrome Tumors through Basal to Squamous Cell Carcinoma Transition.

Although basal cell carcinomas arise from ectopic Hedgehog pathway activation and can be treated with pathway inhibitors, sporadic basal cell carcinomas display high resistance rates, whereas tumors arising in patients with Gorlin syndrome with germline Patched (PTCH1) alterations are uniformly suppressed by inhibitor therapy. In rare cases, patients with Gorlin syndrome on long-term inhibitor therapy will develop individual resistant tumor clones that rapidly progress, but the basis of this resistance remains unstudied. In this study, we report a case of an SMO inhibitor-resistant tumor arising in a patient with Gorlin syndrome on suppressive SMO inhibitor for nearly a decade. Using a combination of multiomics and spatial transcriptomics, we define the tumor populations at the cellular and tissue level to conclude that Gorlin tumors can develop resistance to SMO inhibitors through the previously described basal to squamous cell carcinoma transition. Intriguingly, through spatial whole-exome genomic analysis, we nominate PCYT2, ETNK1, and the phosphatidylethanolamine biosynthetic pathway as genetic suppressors of basal to squamous cell carcinoma transition resistance. These observations provide a general framework for studying tumor evolution and provide important clinical insight into mechanisms of resistance to SMO inhibitors for not only Gorlin syndrome but also sporadic basal cell carcinomas.

Signaling Pathways and Therapeutic Strategies in Advanced Basal Cell Carcinoma.

Non-melanoma skin cancers (NMSCs) are the most common human neoplasms world-wide. In detail, basal cell carcinoma (BCC) is the most frequent malignancy in the fair-skinned population. The incidence of BCC remains difficult to assess due to the poor registration practice; however, it has been increasing in the last few years. Approximately, 85% of sporadic BCCs carry mutations in Hedgehog pathway genes, especially in PTCH, SUFU and SMO genes, which lead to the aberrant activation of GLI transcriptional factors, typically silent in cells of adult individuals. The management of advanced BCC (aBCC), both metastatic (mBCC) and locally advanced BCC (laBCC), not candidates for surgical excision or radiotherapy, remains challenging. The discovery of mutations in the Hh signaling pathway has paved the way for the development of Hh pathway inhibiting agents, such as vismodegib and sonidegib, which have represented a breakthrough in the aBCC management. However, the use of these agents is limited by the frequent occurrence of adverse events or the development of drug resistance. In this review, we thoroughly describe the current knowledge regarding the available options for the pharmacological management of aBCCs and provide a forward-looking update on novel therapeutic strategies that could enrich the therapeutic armamentarium of BCC in the near future.