HLA-G, cytokines, and cytokine receptors in the non-aggressive basal cell carcinoma microenvironment

Basal Cell Carcinoma: Comprehensive Review with Emphasis on Scar Tissue Manifestation and Post-Vaccination Incidence

Basal cell carcinoma (BCC) arising within scar tissue is a rare but clinically significant phenomenon. This comprehensive review aims to provide a succinct overview of the current state of knowledge regarding the etiological factors, pathogenesis, clinical presentation, and management of BCC. This study constitutes a literature review pertaining to BCC, with a particular emphasis on BCC developing within scar tissue. It also provides a clinical case presentation of a patient who had developed BCC in a BCG post-vaccination scar and a review of analogous findings available in the existing literature. Despite the fact that an array of mechanisms play a role in injury-related BCC growth, the main mechanism remains ambiguous and yet to be elucidated. The review also includes a detailed description of the various therapeutic options available for BCC, ranging from surgical interventions to novel pharmacological treatments. By examining these intersections, the review seeks to elucidate the potential mechanisms, identify risk factors, and suggest considerations for clinical practice. The findings underscore the importance of vigilant dermatological assessment in patients with scar tissue and those recently vaccinated, aiming to improve early detection and optimize management strategies for BCC.

The Immune Microenvironment in Basal Cell Carcinoma

The immune system plays a key role in the suppression and progression of basal cell carcinoma (BCC). The primary aetiological factor for BCC development is exposure to ultraviolet radiation (UVR) which, particularly in lighter Fitzpatrick skin types, leads to the accumulation of DNA damage. UVR has roles in the generation of an immunosuppressive environment, facilitating cancer progression. Rates of BCC are elevated in immunosuppressed patients, and BCC may undergo spontaneous immune-mediated regression. Histologic and immunohistochemical profiling of BCCs consistently demonstrates the presence of an immune infiltrate and associated immune proteins. Early studies of immune checkpoint inhibitors reveal promising results in BCC. Therefore, the host immune system and tumor responses to it are important in BCC pathogenesis. Understanding these interactions will be beneficial for disease prognostication and therapeutic decisions.

Review of the Tumor Microenvironment in Basal and Squamous Cell Carcinoma

It is widely known that tumor cells of basal and squamous cell carcinoma interact with the cellular and acellular components of the tumor microenvironment to promote tumor growth and progression. While this environment differs for basal and squamous cell carcinoma, the cellular players within both create an immunosuppressed environment by downregulating effector CD4+ and CD8+ T cells and promoting the release of pro-oncogenic Th2 cytokines. Understanding the crosstalk that occurs within the tumor microenvironment has led to the development of immunotherapeutic agents, including vismodegib and cemiplimab to treat BCC and SCC, respectively. However, further investigation of the TME will provide the opportunity to discover novel treatment options.

Induction of pulmonary HLA-G expression by SARS-CoV-2 infection

The non-classical human leukocyte antigen (HLA)-G exerts immune-suppressive properties modulating both NK and T cell responses. While it is physiologically expressed at the maternal-fetal interface and in immune-privileged organs, HLA-G expression is found in tumors and in virus-infected cells. So far, there exists little information about the role of HLA-G and its interplay with immune cells in biopsies, surgical specimen or autopsy tissues of lung, kidney and/or heart muscle from SARS-CoV-2-infected patients compared to control tissues. Heterogeneous, but higher HLA-G protein expression levels were detected in lung alveolar epithelial cells of SARS-CoV-2-infected patients compared to lung epithelial cells from influenza-infected patients, but not in other organs or lung epithelia from non-viral-infected patients, which was not accompanied by high levels of SARS-CoV-2 nucleocapsid antigen and spike protein, but inversely correlated to the HLA-G-specific miRNA expression. High HLA-G expression levels not only in SARS-CoV-2-, but also in influenza-infected lung tissues were associated with a high frequency of tissue-infiltrating immune cells, but low numbers of CD8+ cells and an altered expression of hyperactivation and exhaustion markers in the lung epithelia combined with changes in the spatial distribution of macrophages and T cells. Thus, our data provide evidence for an involvement of HLA-G and HLA-G-specific miRNAs in immune escape and as suitable therapeutic targets for the treatment of SARS-CoV-2 infections.

Platelet-Rich Plasma Facial Rejuvenation: Myth or Reality?

Platelet-rich plasma (PRP) rejuvenation's efficacy has been reported by numerous uncontrolled clinical case studies of inconsistent quality rather than large randomized and placebo-controlled trials. It was suggested that PRP could be considered as a valid anti-aging and rejuvenation treatment modality. The current literature review summarizes available evidence so far described in the literature with special critical attention to higher quality comparative studies published over the last 10 years. The few studies that could be retrieved and included in this review documented less favorable results. So far, there is no international consensus on clinical PRP use for esthetic rejuvenation. Whether a mix of growth factors does in fact generate a clinically significant more youthful look and whether PRP injections result in comparable or better rejuvenation than what can be expected from other simpler non-surgical modalities. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .