Aberrant p16, p53 and Ki-67 immunohistochemistry staining patterns can distinguish solitary keratoacanthoma from cutaneous squamous cell carcinoma

Dual cell-penetrating peptide-conjugated polymeric nanocarriers for miRNA-205-5p delivery in gene therapy of cutaneous squamous cell carcinoma

Despite the potential of microRNAs (miRNAs) in suppressing tumorigenesis, the main challenges are achieving tumor-specific selectivity and efficient delivery into cancer cells. In this study, miR-205-5p-loaded polymeric nanoparticles conjugated with dual cell-penetrating peptides (CPPs) were designed for targeting and treating cutaneous squamous cell carcinoma (cSCC). The CPPs, R9, and p28, demonstrated high cell-penetrating/targeting abilities and antitumor activity. The anti-cSCC effect of the nanocarriers was examined using in vitro cellular 2D and 3D models and in vivo spheroid-xenografted murine models. The average size of the dual CPP-conjugated nanocarriers was 193 nm with a zeta potential of 5.7 mV. These nanocarriers were readily internalized by A431 cells, resulting in decreased proliferation compared to naked agomiR and nanoparticles with a single CPP. The nanocarriers induced cell cycle arrest in the G0/G1 stage. By loading the miR-205-5p mimic, the dual CPP-conjugated nanoparticles enhanced cell apoptosis threefold compared to the control, activating caspases and poly(ADP-ribose) polymerase (PARP). The wound healing assay demonstrated that the nanocarriers significantly inhibited the migration and invasion of cSCC cells. Additionally, the CPP-conjugated nanocarriers penetrated cSCC 3D spheroids, reducing spheroidal size and proliferation. In vivo studies demonstrated that the intratumoral CPP-conjugated nanocarriers achieved a 30 % reduction in tumor volume than the PBS control. The number of Ki67-positive cells in the nanocarrier-treated tumor decreased fivefold than the untreated tumors. The nanoparticulate agomiR (1 μM) exhibited no cytotoxicity towards normal keratinocytes. No significant toxicity was observed in the skin and peripheral organs following subcutaneous administration of the nanoparticles in healthy mice. These findings demonstrate that miR-205-5p mimic delivery via dual CPP-conjugated nanocarriers can promote efficient and safe cSCC regression. STATEMENT OF SIGNIFICANCE: Cutaneous squamous cell carcinoma (cSCC) is a highly invasive skin malignancy with limited treatment options. This study introduces dual cell-penetrating peptide (CPP)-conjugated polymeric nanoparticles for delivering miR-205-5p, a tumor-suppressor microRNA, to cSCC cells. The nanosystem enhances cellular uptake, inhibits cell proliferation, and promotes apoptosis in both 2D and 3D tumor models. In vivo, the nanocarriers demonstrate significant antitumor efficacy with minimal toxicity, highlighting their potential as a targeted, non-invasive therapy. This research represents a promising advance in gene therapy for cSCC by combining nanotechnology and CPPs to address challenges in miRNA delivery and tumor targeting.

Clinical and histopathological features of advanced cutaneous squamous cell carcinoma with varying responses to cemiplimab

BACKGROUND

Most patients with unresectable locally advanced cutaneous squamous cell carcinoma (cSCC) benefit from cemiplimab, but some do not respond. Our study aims to identify clinical and histopathological features predicting response to cemiplimab.

PATIENTS AND METHODS

We analyzed 15 patients treated with cemiplimab, assessing clinical, demographic, histopathological, and immunohistochemical characteristics and correlating them with treatment response. Furthermore, effectiveness and safety were evaluated in our cohort.

RESULTS

Our cohort included 12 males and 3 females, with a mean age of 78.1 years. The majority of tumors, accounting for 66.7%, were located in the head and neck region. Treatment was well-tolerated, with only one grade 3 colitis. There was no correlation between immune-related adverse events and treatment response. Non-responders were younger (69.4 vs. 82.5 years). A history of hematological malignancy correlated with poorer response. High mitotic rate, poor tumor differentiation, high vimentin and p53, and low E-cadherin expression were associated with worse response. Conversely, higher intratumoral inflammatory infiltrate density, presence of necrotic areas, and lower mismatch repair-protein staining correlated with better response.

CONCLUSIONS

Cemiplimab is a safe and effective therapy, particularly in elderly patients. Well-differentiated tumors with low proliferative index, intratumoral inflammatory infiltrate, and tumor necrosis may predict better clinical response.

Sulfuric acid-induced skin neoplasms in immunocompetent mice

This study investigates the carcinogenic potential of chronic dermal exposure (16 weeks) to sulfuric acid (SA) in immunocompetent mice. Clinical assessments, histopathological analyses, immunohistochemical analyses and biochemical assays were conducted to evaluate skin irritation, oxidative stress biomarkers and the potential carcinogenic effect of SA. Results indicated that prolonged exposure to SA leads to various alterations in skin structure, notably inflammation, preneoplastic and neoplastic proliferation in hair follicles, as well as hyperkeratosis and acanthosis, resulting in an increased epidermal thickness of 98.50 ± 21.6 μm. Immunohistochemistry analysis further corroborates these observations, showcasing elevated nuclear expression of p53 and Ki-67, with a significant mitotic index of (57.5% ± 2.5%). Moreover, biochemical analyses demonstrate that SA induces lipid peroxidation in the skin, evidenced by a high level of Malondialdehyde and a consequential reduction in catalase activity. These findings suggest that prolonged exposure to SA can induce skin neoplasms, highlighting the need for stringent safety measures in environments where SA is frequently used. This study underscores the potential occupational health risks associated with SA exposure.

The 2023 WHO updates on skin tumors: advances since the 2018 edition

Pathology is pivotal in diagnosing skin tumors, and the precision of diagnosis is crucial to devise customized treatment plans and enhance patient care in dermatology. The latest edition of the World Health Organization's classification of skin tumors serves as a comprehensive compendium, summarizing and categorizing all recent advancements in both anatomical-pathological and molecular aspects of cutaneous neoplasms. Several relevant advances have been introduced and new entities have been described. While the fundamental structure of the classification remains unchanged, notable additions include three new sections aimed at providing a more exhaustive description of skin lesions: nail unit tumors, skin metastases, and genetic tumor syndromes associated with skin malignancies. Recent strides in molecular pathology have led to significant breakthroughs in decoding the underlying mechanisms of various skin tumors, ranging from adnexal neoplasms to hematolymphoid neoplasms, soft tissue tumors, and melanocytic lesions. Of particular importance is the evolution in our understanding of melanocytic neoplasms, with the introduction of the term "melanocytoma" reserved for lesions exhibiting "intermediate" biological behavior and characterized by specific molecular mutations. The pathologic diagnosis process integrates morphological, immunohistochemical, and molecular features, playing a crucial role in clinical decision-making. The WHO classification serves as a valuable tool in promoting multidisciplinarity in the management of cutaneous neoplasms with the aim of translating novel pathological discoveries into more effective treatments. This review aims to distill the major updates introduced by the new classification, providing a synthesis of the latest scientific insights.

Follicular (Infundibular-Tricholemmal) Squamous Cell Carcinoma: A New WHO Entity. Clinicopathological Features in 103 Cases, Including Follow-Up and Implications for Patient Management

AIMS

Cutaneous follicular (infundibular-tricholemmal) squamous cell carcinoma (FSCC) is a new World Health Organization entity. We present the largest series of published cases, summarizing clinical data, diagnostic criteria, differential diagnosis, and implications for patient management.

METHODS

Cases were identified from 2004 to 2011. Inclusion criteria included discrete attachment(s) of the tumor to the overlying epidermis via follicular infundibula, tricholemmal keratinization, and cellular pleomorphism. Keratoacanthoma and lesions with adjacent bowenoid epidermal dysplasia were excluded.

RESULTS

One hundred three cases of FSCC identified. 48.5% demonstrated completely circumscript borders ( in situ for practical purposes), 12.6% uncertain for invasion (overwhelmingly pushing borders), and only 38.8% as clearly invasive. Follicular mucin in acantholytic spaces within tumor epithelium was a distinctive finding in 57.2% of cases. Clinical data indicated predominance in elderly (median 78.5 years) men (70.4%), with preferential head and neck location (81.6%). Many were clinically suspected as squamous cell carcinoma (48.5%). However, a significant minority were clinically diagnosed as basal cell carcinoma (40.8%). This may reflect that FSCC commonly presented as a papule or nodule (51.3%). By contrast, keratoacanthoma was less frequently suggested (17.2%) and still fewer lesions were suspected to be actinic keratosis/Bowen's disease (13.6%). Follow-up in 82 cases (median 26.5 months, range 3-144) identified 5 (6.1%) local recurrences. There was no instance of metastasis in the subgroup of lesions with completely circumscript borders. Three of 45 (6.7%) patients, with follow-up, considered to have tumors with invasive pushing, and/or infiltrative borders developed lymph node metastases.

CONCLUSIONS

FSCC is identified as a common skin cancer, incorporating historical entities, such as infundibular carcinoma and tricholemmal carcinoma, with readily identifiable histologic features. Correct diagnosis has implications for patient management; a significant subgroup of lesions show completely circumscript borders that are considered in situ for practical purposes.

A pilot study of p53 immunohistochemistry in atypical squamous lesions, using a vulvar scoring system

BACKGROUND

Histopathologic overlap between cutaneous squamous cell carcinoma (cSCC) and its indolent mimics likely leads to the overdiagnosis of cSCC.

OBJECTIVE

To perform a pilot study of the p53 immunohistochemical scoring system developed on vulvar squamous lesions in cSCC.

METHODS

The consistency and reliability of p53 immunostaining using a scoring system developed on vulvar cases, as compared with TP53 genomic sequencing, was studied in an initial cohort of 28 cutaneous cases. p53 labeling was further assessed in an additional 63 cases of atypical squamous lesions, including 20 atypical squamous lesions classified by the authors as benign, 22 cases diagnosed as cSCC without high-risk features, and 21 cases of high-risk cSCC (cSCC-HR).

RESULTS

The concordance of p53 labeling and TP53 sequencing was 82.1%. Four positive patterns of p53 mutation were identified: basal, parabasal/diffuse, null, and cytoplasmic. p53 positivity in atypical, benign squamous lesions (10%) was significantly lower than that of low-risk cSCC (63.6%, p = 0.0004) or cSCC-HR (90.5%, p < 0.0001). p53 positivity in low-risk cSCC versus cSCC-HR was not statistically significant (p = 0.07).

CONCLUSION

p53 Labeling may be a helpful biomarker to support the diagnosis of cSCC and distinguish cSCC from atypical but benign mimics.

High incidence of HPV infection in minors with oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma in minors is considered to be a distinct entity from OSCC in older patients, with an uncertain etiology. Human papillomavirus (HPV) infection may trigger the initiation and promote the progression of OSCC, but these roles have not been firmly established.We aimed to explore the correlation between HPV infection and the development of oral squamous cell carcinoma in minors and know the characteristics of OSCC in young patients more thoroughly.

METHOD

From January 2013 to December 2022,6 cases of OSCC aged < 15 years were selected from the Department of Oral Pathology, Peking University School of Stomatology, Beijing, China. All cases underwent testing for high-risk HPV mRNA infection using the RNA scope technique, and immunohistochemical staining was performed to investigate the expression of p16, pan-cytokeratin (CK), CK5/6, CK7, CK8/18, epidermal growth factor receptor (EGFR), p53, and Ki-67. Furthermore, we reviewed the literature on OSCC in patients aged < 21 years.

CONCLUSIONS

Minors OSCC is associated with HPV infection, and that p16 can serve as an immunohistochemical marker of HPV positivity.

Intralesional methotrexate as non-surgical therapy for giant keratoacanthoma on the nose

Keratoacanthoma is an epithelial tumour derived from hair follicles. Clinical and histopathological features of keratoacanthoma can resemble that of squamous cell carcinoma. Different treatment alternatives have been described over the years including intralesional methotrexate injection. We present an interesting case of treatment of solitary keratoacanthoma lesion on the nose with intralesional methotrexate as non-surgical therapy.