Overexpression of p27KIP1 in seborrheic keratosis

Melanin accumulation in acanthotic seborrheic keratosis: Reduced proliferation and early differentiation of keratinocytes and increased number of melanocytes

Seborrheic keratosis (SK) is a common benign tumour, often associated with hyperpigmentation. To investigate the mechanism of melanin accumulation in SK, we have conducted comprehensive gene expression and histological analyses. We obtained five pairs of skin samples, including non-lesional and SK samples, from the backs of three male Japanese participants aged 40-59 years. To examine melanocytes and keratinocytes in SK, three pairs of skin samples were separated by laser capture microdissection into the basal layer and the other layer in the epidermis. We performed a comprehensive gene expression analysis to identify differentially expressed genes between non-lesional and SK skin, followed by gene ontology and pathway analysis. We found abnormal morphogenesis and cell proliferation in the basal layer, along with increased immune response and impaired cell differentiation and metabolism in the other layer of SK. We focused on cell proliferation and differentiation, as these are directly associated with melanin accumulation. Immunohistochemical analyses of Ki67, keratin 10, and keratin 14 demonstrated the decreases in the proliferation and early differentiation of the epidermis. Contrarily, no significant changes were observed in terminal differentiation markers, filaggrin and loricrin. Although the number of melanocytes was higher in SK than in non-lesional skin, melanogenic activity showed no difference. These results indicated that melanin accumulation in SK is caused by delayed melanin excretion due to reduced turnover around the basal and spinous layers of the epidermis and melanin production due to an increased number of melanocytes. Our findings provide new insights for therapeutic approaches in SK.

Advances in the Etiology, Detection, and Clinical Management of Seborrheic Keratoses

Seborrheic keratoses (SKs) are ubiquitous, generally benign skin tumors that exhibit high clinical variability. While age is a known risk factor, the precise roles of UV exposure and immune abnormalities are currently unclear. The underlying mechanisms of this benign disorder are paradoxically driven by oncogenic mutations and may have profound implications for our understanding of the malignant state. Advances in molecular pathogenesis suggest that inhibition of Akt and APP, as well as existing treatments for skin cancer, may have therapeutic potential in SK. Dermoscopic criteria have also become increasingly important to the accurate detection of SK, and other noninvasive diagnostic methods, such as reflectance confocal microscopy and optical coherence tomography, are rapidly developing. Given their ability to mimic malignant tumors, SK cases are often used to train artificial intelligence-based algorithms in the computerized detection of skin disease. These technologies are becoming increasingly accurate and have the potential to significantly augment clinical practice. Current treatment options for SK cause discomfort and can lead to adverse post-treatment effects, especially in skin of color. In light of the discontinuation of ESKATA in late 2019, promising alternatives, such as nitric-zinc and trichloroacetic acid topicals, should be further developed. There is also a need for larger, head-to-head trials of emerging laser therapies to ensure that future treatment standards address diverse patient needs.

[Expression of epidermal growth factor receptor in patients with insulin resistance and seborrheic keratomas]

AIM

to study the expression of epidermal growth factor receptor (EGFR) in patients with seborrheic keratomas (SK) and insulin resistance (type 2 diabetes mellitus (DM2)) and in those without concomitant carbohydrate metabolic disturbances.

SUBJECTS AND METHODS

80 patients with SK were examined. According to the presence or absence of DM2, the patients were divided into 2 groups: 1) 40 patients with concomitant DM2; 2) 40 people without carbohydrate metabolic disturbances. DM2 was diagnosed on the basis of laboratory studies and an endocrinologist's consultation. Histological and immunohistochemical (IHC) examinations using anti-EGFR antibodies were performed; two intact skin sections from the patients with DM2 and two intact skin sections from those without carbohydrate metabolic disturbances were used as a control.

RESULTS

The ICH examination using anti-EGFR monoclonal antibodies revealed that Group 1 showed intense diffuse membrane staining of more than 50% of the cells in 32 (80%) patients, moderate (30-50% cells) and weak (10-30% cells) staining in 6 (15%) and 2 (5%) patients, respectively. Marked EGFR expression was also noted in two intact skin biopsy specimens taken from patients with DM2. In Group 2, the staining intensity was weak in more than 10% but less than 30% of the SK cells in 28 (70%) patients; moderate EGFR expression was observed in 9 (22.5%) and diffuse, pronounced, staining in more than 50% of the SK cells was in 3 (7.5%) patients. The intact skin biopsy specimens taken from 2 patients without carbohydrate metabolic disturbances displayed a weak EGFR expression in the basal cell layer of the epidermis.

CONCLUSION

EGFR overexpression in SK may be a result of metabolic disorders rather than a diagnostic sign of malignant neoplasms of the internal organs. The increased EGFR expression revealed in patients with SK and concomitant DM2 is caused by insulin resistance and hyperinsulinemia, in which the dysregulation of insulin signal transmission into the cell leads to changes in EGF synthesis and signaling pathway that regulates cell proliferation and growth.

Seborrheic keratosis: current concepts of pathogenesis

The article covers problems of seborrheic keratosis. The authors discuss current concepts of the etiology and pathogenesis of the disease paying special attention to the histology and immunohistochemistry of different forms and diverse clinical presentations. They describe Leser - Trelat syndrome as well as potential neoplastic transformation of seborrheic keratomas and their association with malignant skin neoplasms.