Exploration of potential biomarkers for prurigo nodularis based on plasma-metabolome analysis.

Prurigo nodularis (PN) is a chronic and debilitating skin disease with severe itching that negatively impacts patients' quality of life and mental state. However, the treatment options for PN remain limited. Global metabolomics analysis can offer effective information on energy metabolism, pathogenesis and potential diagnostic biomarkers. No study on metabolomic analysis of PN has been reported. To further understand the mechanisms of PN and analyse the plasma metabolite profiles in patients with PN. Targeted-metabolome analysis of 306 metabolites in plasma from 18 patients with PN and 19 healthy controls was performed using Liquid Chromatography-tandem Mass Spectrometer analysis. We identified 31 differential metabolites. Most acylcarnitines, long-chain fatty acids, alpha-aminobutyric acid, hydroxybutyric acid and lactic acid among these metabolites were up-regulated in patients with PN; in contrast, glucaric acid, suberic acid, bile acid derivatives and most amino acids were down-regulated. Positive correlations exist between glucaric acid and itching severity and acylcarnitines and insomnia. Suberic acid and the Investigator's Global Assessment (IGA) scores correlate negatively. Metabolite variation reflects the dysregulation of energy metabolism and chronic systematic inflammation in PN. Several metabolites, such as glucaric acid, suberic acid and acylcarnitines, merit further study as potential biomarkers of disease severity in PN.

New insight into prurigo nodularis: Proadrenomedullin N-terminal 20 peptide mediates mouse mast cell activation via Mrgprb2.

BACKGROUND: Prurigo nodularis (PN) is a chronic inflammatory skin disorder that is characterized by extremely itchy nodules. Proadrenomedullin N-terminal 20 (PAMP) activates mast cell degranulation via Mas-related G protein-coupled receptor X2 (MRGPRX2), which is associated with pruritus in allergic contact dermatitis. However, the mechanisms underlying the action of PAMP and MRGPRX2 in PN remain unclear. OBJECTIVE: To determine the role of PAMP-induced mast cell activation via MRGPRX2 (mouse homologous Mrgprb2) in PN. METHODS: The expression of PAMP and the number of MRGPRX2-expressing mast cells in the skin biopsies of patients with PN, atopic dermatitis (AD), and healthy participants were analyzed using immunohistochemistry and immunofluorescence, respectively. The biphasic response of PAMP9-20 mediated by Mrgprb2 in mouse peritoneal mast cells (PMC) was validated in vitro using qRT-PCR, ELISA, flow cytometry, and siRNA techniques. RESULTS: PAMP expression and the number of MRGPRX2+ mast cells in lesional PN skin, but not in AD, were elevated compared to healthy skin. PAMP9-20 mediates the immediate and delayed phase responses of PMC, such as degranulation, histamine and ß-hexosaminidase release, and secretion of inflammatory factors such as CCL2, TNF-α, and GM-CSF. These effects were inhibited when Mrgprb2 expression was silenced. Silencing Mrgprb2 did not affect the biphasic response of PMC that was induced by IgE-FcεRI activation. CONCLUSIONS: The results show that PAMP mediates mouse mast cell activation via Mrgprb2, which may be involved in the pathogenesis of PN. The PAMP/ Mrgprb2 pathway, independent of classical IgE signaling, could be developed as a candidate drug target for treating PN.

Molecular mechanisms of pruritus in prurigo nodularis.

Pruritus is the most common symptom of dermatological disorders, and prurigo nodularis (PN) is notorious for intractable and severe itching. Conventional treatments often yield disappointing outcomes, significantly affecting patients' quality of life and psychological well-being. The pathogenesis of PN is associated with a self-sustained "itch-scratch" vicious cycle. Recent investigations of PN-related itch have partially revealed the intricate interactions within the cutaneous neuroimmune network; however, the underlying mechanism remains undetermined. Itch mediators play a key role in pruritus amplification in PN and understanding their action mechanism will undoubtedly lead to the development of novel targeted antipruritic agents. In this review, we describe a series of pruritogens and receptors involved in mediating itching in PN, including cytokines, neuropeptides, extracellular matrix proteins, vasculogenic substances, ion channels, and intracellular signaling pathways. Moreover, we provide a prospective outlook on potential therapies based on existing findings.

Anti-prolactin treatment alleviates lupus conditions by regulating the JAK2-STAT3 pathway.

OBJECTIVES: We previously revealed the role of prolactin (PRL) in antibody production and disease activity in patients with systemic lupus erythematosus. In this study, we sought to determine whether inhibition of PRL could improve lupus-like disease in MRL/lpr mice. METHODS: The expression levels of PRL in various cell types of lupus patients were measured by flow cytometry. The effects of anti-PRL on animal survival, renal histopathology, creatinine, proteinuria, anti-dsDNA antibody, cytokine production, splenomegaly and lymphadenopathy were assessed. The effect of anti-PRL on the Jak2-Stat3 signalling pathway was detected by western blotting. RESULTS: Prolactin was upregulated in B cells, neutrophils, CD4+ T cells, and monocytes isolated from patients with lupus. Furthermore, inhibition of PRL by anti-PRL treatment around the time of onset prolonged the survival of MRL/lpr mice, significantly reduced anti-dsDNA antibody production, and alleviated symptoms of lupus nephritis, splenomegaly, and lymphadenopathy. In addition, anti-PRL-treated mice showed a decrease in the levels of pathogenic cytokines such as IL-21 and IL-6. Furthermore, mechanistically, anti-PRL treatment significantly reduced the levels of p-Jak2 and p-Stat3 in MRL/lpr mice. CONCLUSIONS: In summary, these data suggest that PRL inhibition alleviates lupus-like disease in MRL/lpr mice by modulating the Jak2-Stat3 signalling cascade. More importantly, our results imply the potential of PRL inhibitors and may provide a novel therapeutic approach for lupus.

RNA sequencing reveals the transcriptome profile of the atopic prurigo nodularis with severe itching.

Prurigo nodularis (PN), characterized by inevitable chronicity and severe pruritus, is most frequently associated with atopy compared with other origins. However, the skin transcriptomic profiling of PN arising from atopic dermatitis (AD), so-called atopic PN (APN), remains unclear. We sought to explore the cutaneous transcriptome of APN with severe pruritus and compare it with classic AD. RNA sequencing was performed on the lesional skin from 13 APN to 11 AD patients with severe pruritus (itch numerical rating scale score ≥ 7) and normal skin from 11 healthy subjects. Quantitative real-time polymerase chain reaction and immunochemistry were used for validation. We detected 1085 and 1984 differentially expressed genes (DEGs) in lesional APN skin and lesional AD skin versus normal skin, respectively. In total, 142 itch/inflammation-related DEGs were identified. Itch/inflammation-related DEGs, such as IL-6, IL-10, IL-13, oncostatin M, and IL-4 receptor, had elevated gene transcript levels in both diseases. The itch/inflammation-related DEGs that increased only in APN were mainly neuroactive molecules, while many inflammatory mediators such as T helper 22-related genes were found to be increased only in AD. Both disorders showed mixed Th1/Th2/Th17 polarisation and impaired skin barrier. In contrast to AD, M1/M2 macrophage activation, tumor necrosis factor production, fibrosis, revascularization and neural dysregulation are unique features of APN. The study findings broaden our understanding of the pathogenesis underlying APN, which provides insights into novel pathogenesis with potential therapeutic implications.

Characterization of chromatin accessibility in psoriasis.

The pathological hallmarks of psoriasis involve alterations in T cell genes associated with transcriptional levels, which are determined by chromatin accessibility. However, to what extent these alterations in T cell transcriptional levels recapitulate the epigenetic features of psoriasis remains unknown. Here, we systematically profiled chromatin accessibility on Th1, Th2, Th1-17, Th17, and Treg cells and found that chromatin remodeling contributes significantly to the pathogenesis of the disease. The chromatin remodeling tendency of different subtypes of Th cells were relatively consistent. Next, we profiled chromatin accessibility and transcriptional dynamics on memory Th/Treg cells. In the memory Th cells, 803 increased and 545 decreased chromatin-accessible regions were identified. In the memory Treg cells, 713 increased and 1206 decreased chromatin-accessible regions were identified. A total of 54 and 53 genes were differentially expressed in the peaks associated with the memory Th and Treg cells. FOSL1, SPI1, ATF3, NFKB1, RUNX, ETV4, ERG, FLI1, and ETC1 were identified as regulators in the development of psoriasis. The transcriptional regulatory network showed that NFKB1 and RELA were highly connected and central to the network. NFKB1 regulated the genes of CCL3, CXCL2, and IL1RN. Our results provided candidate transcription factors and a foundational framework of the regulomes of the disease.

The exosome of platelet endothelial cell adhesion molecule-1 (PECAM1) protein: A potential risking star in high blood pressure patients (HBPP).

ABSTRACT: A number of studies have demonstrated that exosomes were involved in important physiological and pathological processes through cell-to-cell communication in cardiovascular disease, which contained nucleic acids, proteins, and lipid contents. In our study, we found that the protein platelet endothelial cell adhesion molecule-1 (PECAM1) was an extracellular vesicle in the blood of high blood pressure patients (HBPP).Isolated the vesicles from the blood of HBPP and health examiners and detected its size and morphology with nanoparticle tracking analysis, then we identified its surface protein CD63, CD81, and the protein expression of PECAM1 in the exosome with western blot. Furthermore, we analyzed the correlation between the expression of PECAM1 and the high blood degree with linear regression analysis.Our results showed that the morphology of extracellular vesicles was more evident in high blood pressure groups than healthy controls, and the protein expression of PECAM1 was also abundant in the vesicles of HBPP, however, there were no extracellular vesicles in the blood samples of healthy controls. Besides, linear regression showed the linear correlation coefficient R = 0.901, P < .01 between the expression of PECAM1 and the systolic blood pressure of the high blood patients. Therefore, the exosome of protein of PECAM1 was a potential risking star in HBPP.

Photopatch testing in Chinese patients: A 5-year experience.

BACKGROUND: In 2015, a Chinese expert consensus on photopatch testing (PPT) was established, based on European consensus methodology. OBJECTIVES: To update current information on the prevalence of photoallergic contact dermatitis (PACD) to 20 photoallergens and their clinical relevance in the Chinese context. METHODS: A retrospective analysis of 2372 patients who performed PPT in a tertiary referral center in China between 2015 and 2019 was completed. A total of 1208 PACD reactions were observed in 897 (37.8%) patients, and 413 reactions were of current or past relevance. RESULTS: The proportion of reactions of current or past relevance was 34.2%. The most frequent photoallergens were chlorpromazine, thimerosal, potassium dichromate, and formaldehyde. The ultraviolet absorbers, benzophenone and Para-aminobenzoic acid, showed opposite gender distribution to PACD. Twenty-five patients (1.9%) developed PACD reactions to a newly added photoallergen preparation - fragrance mix I. Patients with chronic actinic dermatitis, widespread exposed-site or generalized dermatitis, and older age were more likely to have PACD. CONCLUSIONS: This study is the first to profile PACD reactions with clinical relevance in China. The prevalence of PACD to culprit photoallergens was affected by regional peculiarities. Attention needs to be paid to the age, body-site distribution, and known diagnoses of patients for the identification of PACD.

Loss of ACSM3 confers worsened prognosis and immune exclusion to cutaneous melanoma.

Aim: Malignant melanoma (MM) is a highly aggressive cutaneous cancer with undetermined underlying genetic disposition. We aim to evaluate prognostic and mechanistic role of ACSM3 in MM. Methods: In silico reproduction of TCGA MM dataset, GEO dataset, GDSC dataset and human protein atlas was performed to establish differential expression of ACSM3. In vitro and in vivo validation using A375 and SKMEL1 MM cells were performed to profile tumorigenic role and functional attribution of the gene. Results: ACSM3 expression was significantly downregulated in MM. Lower expression of ACSM3 conferred worsened prognosis of MM. Lower ACSM3 was observed in Asian ethnicity. Knock-down (KD) and overexpression (OE) of ACSM3 resulted in significant increased and decreased proliferation, invasion and colony formation in MM cells, respectively. Pathway annotation revealed significantly active immune response invoked by ACSM3. Lower ACSM3 expression was associated with decreased CD8+, macrophage and dendritic cell infiltration. Cox regression revealed loss of survival contribution of ACSM3 in the presence of immune infiltrates supporting immune regulatory role of ACSM3. Drug sensitivity analysis revealed BRAF inhibitor PLX-4720 was sensitive in both MM cells. ACSM3 expression showed no correlation with immune checkpoint molecules. Combined ACSM3-OE and PLX-4720 in MM cells showed synergistic inhibition in MM cells and xenograft murine models with no significant toxicity. Conclusion: Loss of ACSM3 was associated with poor prognosis in MM. Overexpression of ACSM3 synergistically inhibited MM with PLX-4720. ACSM3 was potentially associated with immune exclusion in MM. Further validation was warranted in future studies.

Treatment-related adverse events as surrogate to response rate to immune checkpoint blockade.

BACKGROUND: Immune checkpoint blockade (ICB) brings hope to many late-stage cancer patients yet its marker for response remains elusive. METHODS: We developed a hypothesis that treatment-related adverse events (TrAEs) could predict objective response rate (ORR) to ICB. We plotted ORR against corresponding any and grade 3 to 5 (G3-5) TrAEs across a variety of cancer types by performing a meta-analysis using linear regression. RESULTS: We identified 113 eligible studies encompassing 25 types of malignancies that were treated with ICB or ICB-based regimes. A significant linear correlation was observed for any and severe TrAEs, respectively. The correlation coefficient was 0.57 (r = 0.324) for any TrAE and 0.61 (r = 0.37) for G3-5 TrAE. For melanoma, the correlation coefficient was 0.81 (r = 0.57) for any TrAE and 0.65 (r = 0.42) for G3-5 TrAEs. For RCC, the correlation coefficient was 0.86 (r = 0.74) for any TrAE and 0.91 (r = 0.83) for G3-5 TrAE. For NSCLC, the correlation coefficient was 0.55 (r = 0.3) for any TrAE and 0.74 (r = 0.86) for G3-5 TrAE. For UC, the correlation coefficient was 0.47 (r = 0.68) for any TrAE and 0.27 (r = 0.52) for G3-5 TrAE, yet the correlation was insignificant for severe AEs. CONCLUSION: Our findings suggest that over half of ICB responses could be reflected by any adverse events and ∼60% of responses could be reflected by severe AEs. Further validation is needed in individual trials.

Comprehensive analysis of copy number variance and sensitivity to common targeted therapy in clear cell renal cell carcinoma: In silico analysis with in vitro validation.

BACKGROUND: Chromosomal rearrangements are common in clear cell renal cell carcinoma (ccRCC) and their roles in mediating sensitivity to tyrosine kinase inhibitors (TKIs) and mTOR inhibitors (mTORi) remain elusive. METHODS: We developed an in silico strategy by screening copy number variance (CNV) that was potentially related to TKI or mTORi sensitivity in ccRCC by reproducing the TCGA and GDSC datasets. Candidate genes should be both significantly prognostic and related to drug sensitivity or resistance, and were then validated in vitro. RESULTS: ADCYAP1 loss and GNAS gain were associated with sensitivity and resistance and to Cabozantinib, respectively. ACRBP gain and CTBP1 loss were associated with sensitivity and resistance and to Pazopanib, respectively. CDKN2A loss and SULT1A3 gain were associated with sensitivity and resistance and to Temsirolimus, respectively. CCNE1 gain was associated with resistance to Axitinib and LRP10 loss was associated with resistance to Sunitinib. Mutivariate analysis showed ADCYAP1, GNAS, and CCNE1 remained independently prognostic when adjusted for the rest. CONCLUSION: Here we show CNVs of several genes that are associated with sensitivity and resistance to commonly used TKIs and mTORi in ccRCC. Further validation and functional analyses are therefore needed.

Characterisation of community-acquired Staphylococcus aureus causing skin and soft tissue infections in a children's hospital in Shanghai, China.

Community-acquired Staphylococcus aureus is a major pathogen responsible for skin and soft tissue infections (SSTIs). This study aimed to investigate the prevalence and molecular characteristics of community-acquired S. aureus isolates recovered from paediatric patients with SSTIs in Shanghai, China. Between January 2015 and January 2018, 91 community-acquired S. aureus isolates were characterised by antibiotic susceptibility, multilocus sequence typing (ST), staphylococcal protein A gene (spa) type and virulence genes. Methicillin-resistant S. aureus (MRSA) strains were also characterised by staphylococcal cassette chromosome mec (SCCmec) type. Forty-one (45.1%) S. aureus isolates were MRSA. ST59 (33.0%, 30/91) was the most common sequence type, and t437 (18.7%, 17/91) was the most common spa type. SCCmec IV and V accounted for 61.0% and 34.1% of all MRSA isolates, respectively. Each isolate carried at least six virulence genes. The positive rates of Panton-Valentine leukocidin genes among all S. aureus, MRSA and methicillin-susceptible S. aureus isolates were 30.8% (28/91), 39.0% (16/41) and 24% (12/50), respectively. The prevalence of community-associated MRSA was surprisingly high among children with community-acquired SSTIs in Shanghai. ST59-t437 was the most prevalent community-acquired S. aureus clone causing SSTIs.

Resveratrol Exerts Therapeutic Effects on Mice With Atopic Dermatitis.

INTRODUCTION: Atopic dermatitis (AD) is a chronic inflammatory skin disease with a high prevalence in children worldwide. Resveratrol exerts various pharmacologic effects, and application of resveratrol has been suggested as an alternative treatment for microorganism infection and skin pathologies. OBJECTIVE: The present study examines the effect of resveratrol on AD using an in vivo murine model. MATERIALS AND METHODS: Atopic dermatitis was induced in 30 BALB/c mice by topical application of 2,4-dinitrochlorobenzene (DNCB) prior to treatment with 0 mg/kg, 5 mg/kg, or 25 mg/kg resveratrol. Histologic data changes were evaluated, and the levels of thymus- and activation-regulated chemokine; type 2 helper T cytokines interleukin (IL) 4, IL-5, and IL-13; and type 1 helper T cytokines IL-12 and interferon γ were examined by enzyme-linked immunosorbent assay. Messenger ribonucleic acid expression was evaluated with quantitative polymerase chain reaction. Filaggrin (FLG), envoplakin (EVPL), transglutaminase (TG), and kallikrein 7 (KLK7) protein expression were evaluated with Western blot. RESULTS: Resveratrol ameliorated the onset of AD-like skin lesions and significantly improved the DNCB-induced dermal destruction in mice. In addition, resveratrol reduced the levels of the above chemokines, downregulated the expression of the proinflammatory cytokine KLK7, and upregulated the expression of several cytokines, such as EVPL, FLG, and TG. CONCLUSIONS: These results suggest resveratrol has therapeutic effects in the treatment of AD.

Variable levels of apoptotic signal-associated cytokines in the disease course of patients with Stevens-Johnson syndrome and toxic epidermal necrolysis.

BACKGROUND/OBJECTIVES: Keratinocyte death is a hallmark of Stevens-Johnson syndrome and toxic epidermal necrolysis (SJS/TEN). Apoptotic signal-associated cytokines, such as TNF-α, sFasL, granulysin, sTRAIL and IFN-γ have been reported to participate in keratinocyte apoptosis. However, their levels are variable, which hampers the elucidation of the role of these cytokines. We sought to determine whether cytokine levels vary with disease course. METHODS: The serum cytokine levels of 24 patients and blister fluid of 10 were analysed by enzyme-linked immunosorbent assay on the first day of their admission to hospital and were evaluated at different time points in the disease course. Meanwhile, surface markers (CD3, CD4, CD8, CD1a, CD14, CD16+56 and CD68) of blister fluid cells were measured by flow cytometry. RESULTS: The concentrations of all cytokines in the serum and blister fluid were higher than those in the controls and were more elevated in the blister fluid than in the serum. Moreover, sTRAIL, IFN-γ and TNF-α quantities were relatively stable, while those of sFasL and granulysin decreased rapidly in the disease course. On the first day, CD8+ T and natural killer cells were predominant in the blister fluid but their relative percentage diminished gradually, while that of CD14+ cells increased. CONCLUSION: Our study confirmed there are high but variable levels of these cytokines in SJS/TEN, especially in the early phase and different tendencies are manifested in the disease course.

Photopatch Testing in Chinese Patients Over 10 Years.

BACKGROUND: Photoallergic contact dermatitis (PACD) is a hypersensitivity reaction that occurs when a previously photosensitized exogenous agent comes into contact with UV radiation. The best method for testing PACD is photopatch testing (PPT). OBJECTIVES: The primary objective of the study was to determine the frequency of PACD to 20 different photoallergens in common usage in China during a 10-year period. METHODS: All patients (n = 6153) who had PPTs done between 2005 and 2014 at the Department of Dermatology of Huashan Hospital, Fudan University, were included. RESULTS: A total of 3767 PACD reactions in 3668 subjects (59.61%) were recorded. Of these allergens, chlorpromazine (CPZ) (51.82%), para-aminobenzoic acid (11.94%), thimerosal (9.81%), potassium dichromate (6.37%), sulfanilamide (5.38%), and formaldehyde (4.7%) were the top 6 allergens that elicited PACD reactions. A comparison of PACD reactions between January 2005 to December 2009 and January 2010 to December 2014 revealed a statistically significant decrease in PACD reaction for chlorpromazine, potassium dichromate, p-aminobenzoic acid, and p-phenylenediamine. Formaldehyde showed a trend toward a statistically significant increase in sensitization over the 10-year period. CONCLUSIONS: In conclusion, positive PACD reactions were most frequent to chlorpromazine in our population. New allergens such as potassium dichromate and formaldehyde should be added to the test series.

Activation of the Blood Coagulation System in Patients with Chronic Spontaneous Urticaria.

BACKGROUND: Ninty-five percent of chronic spontaneous urticaria (CSU) patients presented with signs of thrombin generation, and autologous plasma skin tests score positive. The aim of this study was to assess the initiators of blood coagulation that lead to thrombin generation and fibrinolysis in CSU patients. METHODS: The plasma level of activated factor VII, activator factor XII, fragment F1+2, and D-dimer were measured and analyzed in 103 patients with CSU and 76 control subjects. RESULTS: Mean D-dimer plasma levels were higher in patients than controls (0.41 ± 0.44 µg/mL vs. 0.21 ± 0.26 µg/ mL; p < 0.001). Mean F1+2 plasma levels were higher in patients than controls (11.17 ± 17.65 nM vs. 5.97 ± 9.42 nM; p = 0.048). Mean FVIIa plasma levels were higher in patients than controls (4.09 ± 4.22 ng/mL vs. 2.97 ± 1.59 ng/mL; p = 0.031). However, no significant difference was found on FXIIa plasma levels. On the other hand, all the coagulation factors (D-dimer, FVIIa, and F1+2) were significantly correlated with disease severity. CONCLUSIONS: The extrinsic pathway of the clotting cascade is activated in CSU and is correlated with the disease severity. The involvement of the coagulation pathway in CSU opens new perspectives for a better understanding of the pathogenesis and treatment of the disease.

Evaluation of photodynamic therapy using topical aminolevulinic acid hydrochloride in the treatment of condylomata acuminate.

OBJECTIVES: To investigate the efficacy and safety of topical application of 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) for the treatment of condylomata acuminata (CA) in larger population. METHODS: Patients with CA were given a treatment of ALA-PDT once a week for 3 weeks and followed up at 4, 8, 12 and 24 weeks after the treatment finished. RESULTS: In 531 patients, a clearance rate was observed 95.27%. The rates rouse with PDT cycles. The clearance rate of three PDT cycles was significant higher than one PDT cycles (P < 0.001) and two PDT cycles (P < 0.001). The clearance rate (88.73%) of small lesions (diameter small than 5mm) was significant higher than that (97.74%) of larger lesions (P < 0.001). The clearance rate varied with the location of the lesions. The clearance rate of urethral meatus was highest and that of perianal was lowest. Follow-up for patients with complete response lasted for 24 weeks. The recurrence rate was 5.65%, 11.30%, 15.07%, 15.44% and 16.20% after 1, 4, 8, 12 and 24 weeks. The recurrence rate varied with the location of the lesions. The recurrence rate of perianal was highest and that of labium was lowest. The side effects mainly included flare, pain, erosion, ulcer, and hyperpigmentation. The adverse reaction rate was 7.72%, 8.10%, 2.26%, 0.94% and 0.19%. Sexual dysfunction and urethral malformations were not observed during the 24 weeds visit. CONCLUSION: Topical application of ALA-PDT is a simple and as effective therapy with a lower incidence of adverse effects in the treatment of condylomata acuminata.

Cyclin D1 expression in Bowen's disease and cutaneous squamous cell carcinoma.

Cyclin D1 is a member of the G1 cyclin family that regulates the transition through the G1 phase of the cell cycle and is involved in the neoplastic transformation of certain tumors. This study was designed to investigate the expression of cyclin D1 in Bowen's disease (BD) and cutaneous squamous cell carcinoma (SCC). Biopsies of 30 cases with BD and 24 cases with SCC confirmed by histopathology were obtained from the Department of Dermatology of Huashan Hospital, Shanghai, China. EnVision immunohistochemical technology with a semiquantitative immunohistochemical score was applied to detect the expression of cyclin D1. Of the 24 specimens with SCC, cyclin D1 was found to be positive in 17 (70.8%), whereas of the 30 specimens with BD, cyclin D1 was found to be positive in 13 (43.3%). The expression of cyclin D1 was significantly higher in the SCC compared to that in the BD group. We did not observe a significant association of cyclin D1 expression with different pathological grades of SCC. In conclusion, cyclin D1 plays a significant role as a diagnostic marker in skin tumors and its overexpression was not found to be correlated with the degree of differentiation of SCC.