Cutaneous squamous cell carcinoma (cSCC) is the second most common human skin tumor. In recent years, the incidence of cSCC is increasing annually. Although most cSCC is curable after basic treatment, the advanced cSCC progresses rapidly and poses a significant risk for the impact on quality of life and death. In 2017, the latest version of cSCC management guideline was developed by the American Academy of Dermatology (AAD) based on extensive evidence-based medical evidence, including cSCC biopsy techniques, histopathological assessment, clinical staging and grading, surgical and nonsurgical treatment, follow-up, recurrence prevention, and management of the advanced cSCC. The purpose of this article is to briefly introduce and interpretate this guideline.
Objective To investigate the proteomic changes among normal skin tissues in young and elderly people and cutaneous squamous cell carcinoma (cSCC) tissues in elderly patients with cSCC, find proteins associated with skin aging and cSCC, and provide a new basis for target screening for cSCC therapy. Methods Five cSCC tissue samples from 5 elderly patients with cSCC and 10 normal skin tissue samples from 5 young and 5 elderly people removed during surgery between January 2019 and December 2020 in West China Hospital of Sichuan University were selected. The differences in tissue morphology and structure were observed by hematoxylin-eosin staining, and the whole protein group was qualitatively and quantitatively analyzed by pressure cycle technique. Results With aging, the structure of skin tissues underwent corresponding changes, including thinning of the skin, increased collagen fiber density, and more organized arrangement. Compared to normal skin tissue, cSCC tissue exhibited epithelial cell dysplasia, atypical mitoses, nest-like distribution of cancer cells, infiltration of inflammatory cells, and formation of keratin pearls. Proteomic analysis identified 3008 specific proteins, and there were 37 proteins with common differential expression. Further screening of databases identified 8 proteins derived from the extracellular matrix, primarily involved in morphological structure formation, tensile strength, interaction with platelet-derived growth factors and receptors, collagen degradation metabolism, and cell adhesion. Conclusions Aging leads to changes in skin structure. The changes of tissue structure caused by aging lead to the weakening of skin barrier function. At the same time, aging leads to the down-regulated expression of protein with the function of inhibiting tumor progression and the up-regulated expression of protein with the function of promoting tumor progression in extracellular matrix. These changes may affect the occurrence and development of cSCC by affecting the regulation mechanism of tumor extracellular microenvironment.