Yosuke Ishitsuka

Recent advances in dermatomyositis-specific autoantibodies.

Purpose of reviewIn dermatomyositis, disease-specific autoantibodies now cover more than 70% of patients. These autoantibodies closely correlate with distinct clinical manifestations. In the past few years, extensive evidence has been accumulated on clinical significance of dermatomyositis-specific autoantibodies including autoantibodies against melanoma differentiation antigen 5 (MDA5), transcriptional intermediary factor 1 (TIF1), nuclear matrix protein 2 (NXP2), and small ubiquitin-like modifier activating enzyme (SAE). Recent findingsAnti-MDA5 antibodies are found with high specificity in clinically amyopathic dermatomyositis presenting rapidly progressive interstitial lung disease (ILD) especially in Asian population. Similar tendency has been reported in the US/Europe, although the frequency of positivity and the type of ILD may differ. Anti-TIF1 antibodies are present in juvenile and adult dermatomyositis patients with close correlation with malignancy in adult population. Anti-NXP2 antibodies share similar phenotype with anti-TIF1 antibodies, except that anti-NXP2 antibodies are associated with calcinosis and severe muscle disease. Although numbers are still small, patients with anti-SAE antibodies tend to present skin disease first and then progress to muscle weakness with systematic symptoms including dysphagia. Moreover, distinct cutaneous manifestations and muscle histopathology findings for each autoantibody have been reported. Summary‘Autoantibody-based classification’ of dermatomyositis subsets is now a useful strategy for comprehending the heterogeneous spectrum of dermatomyositis.

Modified gluteal‐fold flap for the reconstruction of vulvovaginal defects

Background  Reconstruction of vulvovaginal defects after tumor excision requires good‐quality skin cover because of the cosmetic and functional importance of this region. Although numerous techniques for vulvovaginal reconstruction have been described, an ideal approach has yet to be widely accepted.

NF1 gene silencing induces upregulation of vascular endothelial growth factor expression in both Schwann and non-Schwann cells.

Neurofibromatosis type I (NF1) is associated with typical hypervascular tumors, including neurofibroma, glioma, malignant peripheral nerve sheath tumors (MPNST) and glomus tumors. Previously, we and other groups reported that neurofibromas showed high‐level expression of vascular endothelial growth factor (VEGF), a potent angiogenic factor involved in neovascularization. However, the molecular mechanism underlying the upregulation of VEGF in neurofibromas remains unclear. In this study, we examined the effects of Nf1 gene silencing on VEGF expression in Schwann cell and non‐Schwann cell line and the upstream mTOR‐HIF‐1α – VEGF pathway in Schwann cell line. The results indicated that Nf1 gene silencing by lentiviral‐mediated RNA interference resulted in elevated expression of VEGF, HIF‐1α and phosphorylated mTOR at the protein level. The results obtained from Nf1 gene silencing in murine Schwann cell line analogously suggest that NF1 gene haploinsufficiency in human tumor Schwann cells may directly elicit upregulation of VEGF expression without the tumor microenvironment by activation of the mTOR‐HIF‐1α – VEGF pathway. We also showed that interleukin‐6 is upregulated in Nf1 gene knock‐down Schwann cells at the protein level.

Overexpression of the Transcription Factor Yin-Yang-1 Suppresses Differentiation of HaCaT Cells in Three-Dimensional Cell Culture

Yin-Yang-1 (YY1) is a member of the GLI-Krüppel family of transcription factors, and both YY1 mRNA and protein expression have been identified in a number of different tissues and cell types suggesting that it is expressed both constitutively and ubiquitously. In epidermal tissue, however, we reported previously that YY1 protein is expressed at high levels in undifferentiated basal keratinocytes and is downregulated during differentiation toward the suprabasal layers. This differential expression pattern during keratinocyte differentiation suggests that YY1 may have an important role in regulating keratinocyte differentiation. In this study, we examined the role of YY1 in differentiation of the human keratinocyte cell line HaCaT using air-liquid interface three-dimensional culture. The constitutive overexpression of YY1 in HaCaT cells during air exposure-induced differentiation resulted in an undifferentiated phenotype, thickening of the stratified layers, suppression of differentiation marker expression, and retention of proliferative activity. These findings suggested that YY1 may have an important role in maintenance of the undifferentiated phenotype of keratinocytes in the basal epidermal layer, and that reduction of YY1 expression in the suprabasal layers may allow keratinocytes to differentiate and move toward the upper layers of the epidermis.

Pituitary Tumor Transforming Gene 1 Induces Tumor Necrosis Factor-α Production from Keratinocytes: Implication for Involvement in the Pathophysiology of Psoriasis

Proliferation and differentiation in the epidermis must be tightly regulated. This regulation is known to involve a range of transcription factors, including pituitary tumor transforming gene 1 (PTTG1), a ubiquitously distributed transcription factor that regulates keratinocyte proliferation and differentiation. Psoriasis is a common but refractory skin disorder, the pathophysiology of which is characterized by hyperproliferation and impaired differentiation in the epidermis. The present study was conducted to clarify the less well-known roles of PTTG1 in the pathophysiology of psoriasis, focusing on its relationship with tumor necrosis factor-α (TNF-α), which is a critical mediator of the disease. The levels of PTTG1 expression were increased in the psoriatic epidermis. Overexpression of PTTG1 resulted in the overproduction of TNF-α, and TNF-α itself had an inductive effect on PTTG1 expression, suggesting that their expression may involve autoinduction. Moreover, overexpression of PTTG1 involved augmented the expression of cyclin A and B1 proteins in both cultured keratinocytes and the psoriatic epidermis. Therefore, enhanced expression of PTTG1 in the psoriatic epidermis may result in aberrant regulation of the cell cycle and impaired differentiation via the interplay between PTTG1 and TNF-α.

Malignant Blue Nevus Arising in a Giant Congenital Cellular Blue Nevus in an Infant

Abstract:  Giant congenital blue nevus (GCBN) is rare and usually occurs on the scalp. Malignant blue nevus (MBN) is also rare and has a poor prognosis. We report a case of MBN arising in a GCBN on the back. There have been three previous reports of MBN associated with GCBN on the trunk; our case had the earliest onset of MBN arising in a GCBN.

Pituitary Tumor-Transforming Gene 1 Enhances Proliferation and Suppresses Early Differentiation of Keratinocytes

The epidermis is a self-renewing tissue, the homeostasis of which is dependent upon the tight balance between proliferation and differentiation based on appropriate regulation of the cell cycle. The cell cycle regulation is dependent on the interactions among a number of cell cycle regulatory molecules, including the pituitary tumor-transforming gene 1 (PTTG1), also known as securin, a regulator of sister chromatid separation and transition from metaphase to anaphase. This study was conducted to clarify the less-known functions of PTTG1 in the epidermis by the use of keratinocytes cultured under two-dimensional (2D) or three-dimensional (3D) conditions. Forced overexpression of PTTG1 caused upregulation of cyclin B1, cyclin-dependent kinase 1 (CDK1), and c-Myc, resulting in enhanced proliferation and suppression of early differentiation without apparent alterations in terminal differentiation, and the exogenous PTTG1 was downregulated in association with cell cycle exit. In contrast, depletion of PTTG1 caused their downregulation and constrained proliferation with retention of differentiation capacity. These findings suggested that PTTG1 could alter the proliferation status by modulating the expression levels of the other cell cycle regulatory proteins, and excess PTTG1 primarily affects early differentiation of keratinocytes under the stability regulation associated with cell cycle exit.

Basal cell carcinoma on the dorsum of the foot with inguinal and pelvic lymph nodes metastases.

Background  Although basal cell carcinoma (BCC) is the most common type of skin cancer, the incidence of metastasis is exceedingly low.

Pituitary tumor-transforming gene 1 as a proliferation marker lacking prognostic value in cutaneous squamous cell carcinoma

Non‐melanoma skin cancer is the most frequently occurring type of cancer worldwide and is caused by epidermal carcinogenesis and malignant progression that involve dysregulated expression of proto‐oncogenes and tumor suppressor genes. The proto‐oncogene pituitary tumor‐transforming gene 1 (PTTG1) is a ubiquitously expressed transcription factor that can promote enhanced proliferation of cultured epidermal keratinocytes. To investigate the potential roles of PTTG1 in epidermal carcinogenesis and malignant progression, the expression of PTTG1 was analysed by immunohistochemistry along with Ki67, keratin 10 (K10) and p53 in tissue samples of cutaneous squamous cell carcinomas (SCC), actinic keratoses (AK) and Bowens disease (BD). Expression levels of PTTG1 were compared among these disease groups to test for correlations with proliferation, differentiation capacity or the existence of mutated tumor suppressor genes in each disease group. In each disease group, the expression levels of PTTG1 correlated positively with those of Ki67, although the differentiation status, measured by K10 expression, did not show any correlation. In contrast, the existence of mutated p53 proteins showed a positive correlation only in the SCC group. Moreover, the expression levels of PTTG1 in SCC did not correlate with known prognostic factors such as TNM staging or tumor thickness. These results suggest that PTTG1 may represent a proliferation marker associated with mutated p53 proteins but is not an informative predictor of poor clinical outcomes in SCC.

Cutaneous Angiosarcoma: The Possibility of New Treatment Options Especially for Patients with Large Primary Tumor

The most widely accepted treatment for cutaneous angiosarcoma (CAS) is wide local excision and postoperative radiation to decrease the risk of recurrence. Positive surgical margins and large tumors (T2, >5 cm) are known to be associated with poor prognosis. Moreover, T2 tumors are known to be associated with positive surgical margins. According to previous reports, the majority of CAS patients in Japan had T2 tumors, whereas less than half of the patients in the studies from western countries did so. Consequently, the reported 5-year overall survival of Japanese CAS patients without distant metastasis was only 9%, lower than that for stage-IV melanoma. For patients with T2 tumors, management of subclinical metastasis should be considered when planning the initial treatment. Several attempts to control subclinical metastasis have been reported, such as using adjuvant/neoadjuvant chemotherapy in addition to conventional surgery plus radiation. Unfortunately, those attempts did not show any clinical benefit. Besides surgery, new chemotherapeutic approaches for advanced CAS have been introduced in the past couple of decades, such as paclitaxel and docetaxel. We proposed the use of chemoradiotherapy (CRT) using taxanes instead of surgery plus radiation for patients with T2 tumors without distant metastasis and showed a high response ratio with prolonged survival. However, this prolonged survival was seen only in patients who received maintenance chemotherapy after CRT, indicating that continuous chemotherapy is mandatory to control subclinical residual tumors. With the recent development of targeted drugs for cancer, many potential drugs for CAS are now available. Given that CAS expresses a high level of vascular endothelial growth factor (VEGF) receptor, drugs that target VEGF signaling pathways such as anti-VEGF monoclonal antibody and tyrosine kinase inhibitors are also promising, and several successful treatments have been reported. Besides targeted drugs, several new cytotoxic anticancer drugs such as eribulin or trabectedin have also been shown to be effective for advanced sarcoma. However, most of the clinical trials did not include a sufficient number of CAS patients. Therefore, clinical trials focusing only on CAS should be performed to evaluate the effectiveness of these new drugs.