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Background: In the era of biologic therapy, phototherapy and methotrexate (MTX) are still commonly used for treatment in patients with moderate-to-severe psoriasis. However, the skin cancer risk following a combination of MTX and narrowband ultraviolet B (NB-UVB) has rarely been explored., Objectives: To investigate whether MTX plus NB-UVB increases skin cancer risk in patients with psoriasis., Methods: We conducted a retrospective cohort study of data in the Taiwan National Health Insurance Research Database from 1997 to 2013. Cumulative incidences and multivariate analysis were investigated using a competing risk regression model, comparing skin cancer risk between cohorts of people having combination therapy and those using NB-UVB alone, matched for relative confounders. We further conducted a sensitivity analysis for those receiving a higher MTX dose. Standardized incidence ratios (SIRs) were calculated for skin cancer risk., Results: We enrolled 3203 participants in each cohort. No significant differences in skin cancers were noted between the two cohorts for the cumulative incidences (log-rank test, P = 0.28) and for the hazard ratio (HRs) [adjusted HR 0.50, 95% confidence interval (CI) 0.15-1.63, P = 0.247] in the competing risk regression model. There were also no significant differences between those receiving higher-dose MTX and UVB alone in the cumulative incidences of skin cancers (P = 0.23) and the HR (adjusted HR = 0.29, 95% CI 0.04-2.21, P = 0.23) in the multivariate analysis. There was no significant difference in the SIR between the two cohorts compared with the general population., Conclusions: In the Taiwanese population, MTX does not increase skin cancer risk in patients with moderate-to-severe psoriasis receiving NB-UVB., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists.)

We aimed to develop an accurate and efficient skin cancer classification system using deep-learning technology with a relatively small dataset of clinical images. We proposed a novel skin cancer classification method, SkinFLNet, which utilizes model fusion and lifelong learning technologies. The SkinFLNet's deep convolutional neural networks were trained using a dataset of 1215 clinical images of skin tumors diagnosed at Taichung and Taipei Veterans General Hospital between 2015 and 2020. The dataset comprised five categories: benign nevus, seborrheic keratosis, basal cell carcinoma, squamous cell carcinoma, and malignant melanoma. The SkinFLNet's performance was evaluated using 463 clinical images between January and December 2021. SkinFLNet achieved an overall classification accuracy of 85%, precision of 85%, recall of 82%, F-score of 82%, sensitivity of 82%, and specificity of 93%, outperforming other deep convolutional neural network models. We also compared SkinFLNet's performance with that of three board-certified dermatologists, and the average overall performance of SkinFLNet was comparable to, or even better than, the dermatologists. Our study presents an efficient skin cancer classification system utilizing model fusion and lifelong learning technologies that can be trained on a relatively small dataset. This system can potentially improve skin cancer screening accuracy in clinical practice., (© 2023. Springer Nature Limited.)

Background: Lysosomal cell death is induced by lysosomal membrane permeabilization (LMP) and the subsequent release of lysosomal proteolytic enzymes, including cathepsins (CTSs), which results in mitochondrial dysfunction and apoptosis. Imiquimod (IMQ), a synthetic TLR7 ligand, has both antiviral and antitumor activity against various skin malignancies in clinical treatment. Previously, we demonstrated IMQ not only caused lysosomal dysfunction but also triggered lysosome biogenesis to achieve lysosomal adaptation in cancer cells., Objective: To determine whether lysosomes are involved in IMQ-induced apoptosis., Methods: The human skin cancer cell lines BCC, A375 and mouse melanoma cell line B16F10 were used in all experiments. Cell death was determined by the Cell Counting Kit-8 (CCK-8) assay and DNA content assay. Protein expression was determined by immunoblotting. Caspase-8 activity was assessed using a fluorescence caspase-8 kit and determined by flow cytometry and confocal microscopy., Results: IMQ not only induced lysosome damage but also abrogated lysosome function in skin cancer cells. IMQ-induced caspase-8 activation contributed to the processes of lysosomal cell death. Moreover, the use of ROS scavengers significantly abolished caspase-8 activation and inhibited IMQ-induced LMP. Additionally, pharmacological inhibition of CTSD not only abrogated caspase-8 activation but also rescued IMQ-induced cell death. Finally, lysosome-alkalizing agents enhanced the cytotoxicity of IMQ in vitro and in vivo., Conclusions: IMQ-induced ROS accumulation promotes LMP, releases CTSs into the cytosol, stimulates caspase-8 activation and finally causes lysosomal cell death. Lysosomal cell death and the CTSD/caspase-8 axis may play a crucial role in IMQ-induced cell death., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to declare., (Copyright © 2022 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

The relationship between cancer and vitiligo has been explored but with inconsistent results. To examine the long-term cancer risk in vitiligo patients, we conducted a retrospective nationwide cohort study. From the National Health Insurance Research Database of Taiwan, a total of 13,824 vitiligo patients were identified and matched with 55,296 reference subjects without vitiligo by age, gender, and propensity score estimated by major comorbidities from 1997 to 2013. Demographic characteristics and comorbidities were compared between these two groups. Incidence rate ratios and hazard ratios (HRs) were calculated to examine cancer risks. The 16-year incidence rates of overall cancers were 621.06 (566.56-675.55) and 726.99 (697.24-756.74) per 100,000 person-years in the vitiligo and reference groups. Patients with vitiligo showed a significantly decreased risk of overall cancers [adjusted HR, 0.85; 95% confidence interval (CI), 0.77 to 0.93, p < 0.001] compared with reference subjects without vitiligo after adjusting for age, sex, comorbidities, and treatments. The risks of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) were significantly reduced (adjusted HR 0.21, 95% CI 0.11-0.38, p < 0.001), as well as internal malignancies (adjusted HR 0.89, 95% CI 0.81-0.99, p = 0.026). The results were consistent across different subgroups of patients, including male gender, ages more than 40 years, and those receiving long-term systemic disease-modifying antirheumatic drugs and phototherapies. Information related to phenotype, disease duration, vitiligo lesion sites, family history of vitiligo or cancer, occupation, and personal lifestyle was not included in the database. Vitiligo is associated with reduced risks of BCC and SCC, as well as internal malignancies., (© 2021. The Author(s).)

The induction of immunogenic cell death (ICD) in cancer cells triggers specific immune responses against the same cancer cells. Imiquimod (IMQ) is a synthetic ligand of toll-like receptor 7 that exerts antitumor activity by stimulating cell-mediated immunity or by directly inducing apoptosis. Whether IMQ causes tumors to undergo ICD and elicits a specific antitumor immune response is unknown. We demonstrated that IMQ-induced ICD-associated features, including the surface exposure of calreticulin and the secretion of adenosine triphosphate and HMGB1, were mediated by ROS and endoplasmic reticulum stress. In a B16F10 melanoma mouse model, vaccinating mice with IMQ-induced ICD cell lysate or directly injecting IMQ in situ reduced tumor growth that was mediated by inducing tumor-specific T-cell proliferation, promoting tumor-specific cytotoxic killing by CD8 + T cells, and increasing the infiltration of various immune cells into tumor lesions. The ICD-associated features were crucial in the induction of specific antitumor immunity in vivo. The glycolytic inhibitor 2-deoxyglucose enhanced IMQ-induced ICD-associated features and strengthened the antitumor immunity mediated by IMQ-induced ICD cell lysate in p53-mutant cancer cells, which were IMQ-resistant in vitro. We conclude that IMQ is an authentic ICD inducer and provide a concept connecting IMQ-induced cancer cell death and antitumor immune responses., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Mitochondrial homeostasis is a highly dynamic process involving continuous fission and fusion cycles and mitophagy to maintain mitochondrial functionality. Imiquimod (IMQ), a Toll-like receptor (TLR) 7 ligand, is used to treat various skin malignancies. IMQ also induces apoptotic and autophagic cell death in various cancers through a TLR7-independent pathway., Objective: To investigate whether IMQ-induced ROS production is involved in mitochondrial dysfunction, mitochondrial fragmentation and mitophagy in skin cancer cells., Methods: BCC/KMC-1, B16F10 and A375 skin cancer cells, AGS gastric cancer cells and primary human keratinocytes were treated with 50 μg/mL IMQ. After 4 h, ROS were detected by CM-H 2 DCFDA, DHE, and MitoSOX Red staining. After 24 h, cell viability and the mitochondrial membrane potential were evaluated by a CCK-8 assay and JC-1 staining, respectively. Oxygen consumption was assessed with an Oroboros instrument. Mitochondrial morphology and mitophagy were evaluated by MitoTracker and LysoTracker staining. Mitochondrial dynamics markers, including MFN-1, DRP-1 and OPA1, and mitophagy markers, including LC3, S65-phosphorylated ubiquitin, PINK1 and TOM20, were detected by immunoblotting., Results: IMQ not only induced severe ROS production but also resulted in increased mitochondrial membrane potential loss, mitochondrial fission and mitophagy and decreased oxygen consumption in skin cancer cells compared with normal keratinocytes. Pretreatment with the antioxidant NAC reduced IMQ-induced ROS production and attenuated IMQ-induced mitochondrial fission and mitophagy in skin cancer cells., Conclusions: IMQ-induced ROS might be associated with mitochondrial dysfunction, mitochondrial fission and mitophagy in cancer cells. Alleviating IMQ-induced ROS production would reduce mitochondrial fission-to-fusion skewing and further reduce IMQ-induced mitophagy., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare., (Copyright © 2020 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

Background: Narrowband ultraviolet B (NB-UVB) phototherapy is a widely used treatment for various dermatoses. The risk of skin cancer following long-term NB-UVB phototherapy has rarely been explored in skin phototypes III-V., Methods: We conducted a nationwide-matched cohort study and identified a total of 22 891 psoriasis patients starting NB-UVB phototherapy from the Taiwan National Health Insurance Database during the period 2000-2013. Cumulative incidences of skin cancers were compared between subjects receiving less than 90 UVB treatments (S-cohort, N = 13 260) and age- as well as propensity score-matched subjects receiving more than or equal to 90 UVB treatments (L-cohort, N = 3315)., Results: There were no significant differences in the overall cumulative incidences of skin cancers between the two cohorts (log-rank t test, P = 0.691) during the follow-up periods. The S-cohort had a significantly lower prevalence of actinic keratosis when compared with the L-cohort (0.54% vs 1.00%, P = 0.005)., Conclusion: Long-term NB-UVB phototherapy does not increase skin cancer risk compared with short-term NB-UVB phototherapy in psoriasis patients with skin phototypes III-V., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The tumor suppressor p53 controls DNA repair, cell cycle, apoptosis, autophagy and numerous other cellular processes. Imiquimod (IMQ), a synthetic toll-like receptor (TLR) 7 ligand for the treatment of superficial basal cell carcinoma (BCC), eliminates cancer cells by activating cell-mediated immunity and directly inducing apoptosis and autophagy in cancer cells., Objective: To evaluate the role of p53 in IMQ-induced cell death in skin cancer cells., Methods: The expression, phosphorylation and subcellular localization of p53 were detected by real-time PCR, luciferase reporter assay, cycloheximide chase analysis, immunoblotting and immunocytochemistry. Using BCC/KMC1 cell line as a model, the upstream signaling of p53 activation was dissected by over-expression of TLR7/8, the addition of ROS scavenger, ATM/ATR inhibitors and pan-caspase inhibitor. The role of p53 in IMQ-induced apoptosis and autophagy was assessed by genetically silencing p53 and evaluated by a DNA content assay, immunoblotting, LC3 puncta detection and acridine orange staining., Results: IMQ induced p53 mRNA expression and protein accumulation, increased Ser15 phosphorylation, promoted nuclear translocation and up-regulated its target genes in skin cancer cells in a TLR7/8-independent manner. In BCC/KMC1 cells, the induction of p53 by IMQ was achieved through increased ROS production to stimulate the ATM/ATR-Chk1/Chk2 axis but was not mediated by inducing DNA damage. The pharmacological inhibition of ATM/ATR significantly suppressed IMQ-induced p53 activation and apoptosis. Silencing of p53 significantly decreased the IMQ-induced caspase cascade activation and apoptosis but enhanced autophagy. Mutant p53 skin cancer cell lines were more resistant to IMQ-induced apoptosis than wildtype p53 skin cancer cell lines., Conclusion: IMQ induced ROS production to stimulate ATM/ATR pathways and contributed to p53-dependent apoptosis in a skin basal cell carcinoma cell line BCC/KMC1., (Copyright © 2015 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Background: AMP-activated protein kinase (AMPK), a principal intracellular energy sensor, plays a crucial role in cell growth, proliferation, apoptosis and autophagy. Imiquimod (IMQ) directly exhibits anti-tumor activity through the induction of apoptosis and autophagic cell death., Objective: To evaluate the role of AMPK in IMQ-induced apoptosis and autophagy., Methods: The phosphorylation of AMPK and its substrates was detected by immunoblotting. ATP contents were analyzed by an ATP bioluminescence assay. The upstream signaling for AMPK activation was dissected by examination of TLR7/8 expression, over-expression of TLR7/8, the addition of AMPK kinase inhibitors, and the genetic silencing of Myd88 and LKB1. The role of AMPK activation in IMQ-induced autophagy and apoptosis was assessed by inhibiting AMPK, genetically silencing AMPK and over-expressing AMPK dominant-negative mutants. Autophagy and apoptosis were evaluated by a DNA content assay, immunoblotting, EGFP-LC3 puncta detection and acridine orange staining., Results: IMQ could activate AMPK and autophagy in cancer cells not expressing TLR7/8. IMQ caused ATP depletion and induced LKB1-mediated AMPK activation. The down-regulation of AMPK activity via pharmacological inhibition and genetic silencing resulted in reduced IMQ-induced apoptosis but did not influence autophagy, and this rescue effect was associated with the retention of translation factor activity and anti-apoptotic Bcl-2 family member Mcl-1 protein expression levels., Conclusion: IMQ induces AMPK activation independent of TLR7/8 expression, resulting in translation inhibition and subsequent apoptosis through ATP depletion and LKB1 signaling, in skin tumor cells., (Copyright © 2015 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Compound C, a well-known inhibitor of the intracellular energy sensor AMP-activated protein kinase (AMPK), has been reported to cause apoptotic cell death in myeloma, breast cancer cells and glioma cells. In this study, we have demonstrated that compound C not only induced autophagy in all tested skin cancer cell lines but also caused more apoptosis in p53 wildtype skin cancer cells than in p53-mutant skin cancer cells. Compound C can induce upregulation, phosphorylation and nuclear translocalization of the p53 protein and upregulate expression of p53 target genes in wildtype p53-expressing skin basal cell carcinoma (BCC) cells. The changes of p53 status were dependent on DNA damage which was caused by compound C induced reactive oxygen species (ROS) generation and associated with activated ataxia-telangiectasia mutated (ATM) protein. Using the wildtype p53-expressing BCC cells versus stable p53-knockdown BCC sublines, we present evidence that p53-knockdown cancer cells were much less sensitive to compound C treatment with significant G2/M cell cycle arrest and attenuated the compound C-induced apoptosis but not autophagy. The compound C induced G2/M arrest in p53-knockdown BCC cells was associated with the sustained inactive Tyr15 phosphor-Cdc2 expression. Overall, our results established that compound C-induced apoptosis in skin cancer cells was dependent on the cell's p53 status., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: Imiquimod had been shown to induce apoptosis and autophagy in several skin cancer cells, especially basal cell carcinoma (BCC) cells., Objective: We evaluate the molecular mechanisms of imiquimod-induced apoptosis and autophagy in skin cancer cell lines., Methods: The Mcl-1, Bcl-2 and Bcl-xL proteins were determined by immunoblotting. The Mcl-1 mRNA level was examined by RT-PCR and real-time PCR. The mechanisms of imiquimod-induced decrease in Mcl-1 protein were evaluated by addition of cycloheximide, MG132 proteasome inhibitor or pan-caspase inhibitor. The phosphorylation of eIF4E, 4E-BP1 and eEF2 in imiquimod treated cells were examined by immunoblotting. The imiquimod-induced apoptosis and autophagy were evaluated in Mcl-1-overexpressing cells by XTT test, mitochondrial membrane potential measurement, DNA content assay, LC3 immunoblotting, EGFP-LC3 puncta formation and quantification of acidic vesicular organelle with acridine orange staining., Results: The decrease in the Mcl-1 protein level was faster and stronger than the decrease in Bcl-2 and Bcl-xL in imiquimod-treated skin cancer cells. The imiquimod-induced decrease in Mcl-1 protein was not caused by blocked transcription or the promotion of degradation but was associated with inactivation of translation factors in BCC cells. The Mcl-1-overexpressing BCC cells were more resistant to intrinsic cellular apoptosis than control BCC cells during imiquimod treatment. Mcl-1 overexpression in BCC cells resulted in the basal activation of autophagy but did not modulate imiquimod-induced autophagy or rescue imiquimod-induced autophagic cell death in BCC cells., Conclusions: Imiquimod may rapidly downregulate Mcl-1 protein levels by inhibiting translation in skin cancer cells. Mcl-1 may act to protect against apoptosis but not autophagy and autophagic cell death during imiquimod treatment in skin cancer cells., (Copyright © 2011 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Background: It has been described that Caucasian patients with cutaneous malignant melanoma (CMM) are at an increased risk of developing second primary cancer. However, no large-scale study of second primary cancer in CMM patients has been conducted among Asians, who have distinctly different skin types., Objective: We sought to access the risk of second primary cancer among CMM patients based on data from a nationwide database in Taiwan., Methods: Utilizing the catastrophic illness database of Taiwan's National Health Insurance Research Database, we identified 2665 CMM patients without prior cancers in the period from 1997 to 2008. The standard incidence ratio (SIR) of each cancer was calculated., Results: The mean age ± standard deviation at diagnosis of CMM was 62.2 ± 17.4 years. The mean annual incidence was 0.9 cases per 100,000 people. The overall cancer risk was elevated (SIR: 2.54), with younger patients having a higher risk. The risk remained elevated during the first five years after the CMM diagnosis. CMM patients had a higher risk of developing cancers of eye (SIR: 275.68), connective tissue (SIR: 43.45), brain (SIR: 21.03), and non-melanoma skin cancer (SIR: 17.71)., Conclusion: CMM patients have a 2.54-fold risk of second primary cancer, with younger patients at increased risk. The risk remains elevated during the first five years after the diagnosis of CMM. The sites with highest risk of second primary cancer are eye, connective tissue, brain, and non-melanoma skin cancer., (Copyright © 2010 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.)

Myeloid cell leukemia-1 (Mcl-1, Mcl-1L) is an anti-apoptotic protein of the Bcl-2 family that acts as a critical molecule in apoptosis control. Mcl-1 pre-mRNA can undergo alternative splicing to yield the short isoform, Mcl-1S, which resembles BH3-only pro-apoptotic proteins and induces apoptosis. Overexpression of Mcl-1 may play a role in various human tumors, and Mcl-1 may serve as a target in cancer therapy. In this study, we found an imbalance between the expression levels of Mcl-1L and Mcl-1S in the skin basal cell carcinoma (BCC) cell line when compared with primary keratinocytes. We showed that overexpression of Mcl-1S induces apoptosis in BCC cells. Finally, we showed that Mcl-1 antisense morpholino oligonucleotides (AMOs) can specifically target Mcl-1 pre-mRNA and shift the splicing pattern from Mcl-1L to Mcl-1S mRNA and protein. This shift increases the level of pro-apoptotic Mcl-1S and reduces the level of anti-apoptotic Mcl-1L, which induces apoptosis in BCC cells and AGS cells, a human gastric adenocarcinoma epithelial cell line. Thus, this report provides a strategy for cancer therapy in which AMOs change the alternative splicing pattern of Mcl-1 pre-mRNA and thereby induce apoptosis.

A 14-year-old boy with neurofibromatosis type 1 presented with two ill-demarcated, grayish-white, and atrophic patches on his left back, which were confirmed as neurofibroma by histopathologic examinations. This clinical presentation of neurofibroma has rarely been reported in patients with neurofibromatosis.

Krüppel-like factor 4 (KLF4) is a transcription factor regulating cell growth and differentiation. It has been postulated as a tumor suppressor gene in several tumors including colon cancer and prostate cancer; whereas, it is activated in other tumors such as breast cancer and oropharyngeal carcinomas. To understand the significance KLF4 on clinicopathologic implications in human squamous cell carcinoma skin (SCC) progression, thirty six formalin-fixed paraffin-embedded samples of cutaneous SCC and 28 samples of Bowen's disease were stained with anti-KLF4 antibodies. A semiquantitative evaluation of the degree of staining intensity and localization of expression were analyzed and correlated with histological and clinical features. Nuclear KLF4 staining was seen in differentiated epithelium including suprabasal keratinocyte of non-lesional skin. Strong nuclear KLF4 staining was observed in tumor parts of both SCC and Bowen's disease, when compared with their non-tumor parts (p = 0.001). Increased expression of KLF4 protein and mRNA were found in squamous cell carcinoma cell line studies and fresh skin tissue respectively, using western blotting and semi-quantitative real time polymerase chain reaction (PCR). SCC with moderately and poorly differentiated tumors tend to have maturation independent (MI) staining pattern (p = 0.0004), compared to maturation dependent (MD) staining in well-differentiated tumors. Finally, constitutive nuclear KLF4 staining pattern was significantly associated with moderately and poorly differentiated tumors (p = 0.0006), and tumor metastasis (p = 0.024). We propose that KLF4 expression is associated with human skin SCC progression and metastases.