Cancer-associated fibroblast activation predicts progression, metastasis, and prognosis of cutaneous squamous cell carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is the most common metastatic skin cancer and the metastatic disease is associated with poor prognosis. Cancer-associated fibroblasts (CAFs) promote progression of cancer, but their role in cSCC is largely unknown. We examined the potential of CAF markers in the assessment of metastasis risk and prognosis of primary cSCC. We utilized multiplexed fluorescence immunohistochemistry for profiling CAF landscape in metastatic and non-metastatic primary human cSCCs, in metastases, and in premalignant epidermal lesions. Quantitative high-resolution image analysis was performed with two separate panels of antibodies for CAF markers and results were correlated with clinical and histopathological parameters including disease-specific mortality. Increased stromal expression of fibroblast activation protein (FAP), α-smooth muscle actin, and secreted protein acidic and rich in cysteine (SPARC) were associated with progression to invasive cSCC. Elevation of FAP and platelet-derived growth factor receptor-ß (PDGFRß) expression was associated with metastasis risk of primary cSCCs. High expression of PDGFRß and periostin correlated with poor prognosis. Multimarker combination defined CAF subset, PDGFRα-/PDGFRß+/FAP+, was associated with invasion and metastasis, and independently predicted poor disease-specific survival. These results identify high PDGFRß expression alone and multimarker combination PDGFRα-/PDGFRß+/FAP+ by CAFs as potential biomarkers for risk of metastasis and poor prognosis.

Super Enhancer-Regulated LINC00094 (SERLOC) Upregulates the Expression of MMP-1 and MMP-13 and Promotes Invasion of Cutaneous Squamous Cell Carcinoma.

Long non-coding RNAs (lncRNAs) have emerged as important regulators of cancer progression. Super enhancers (SE) play a role in tumorigenesis and regulate the expression of specific lncRNAs. We examined the role of BRD3OS, also named LINC00094, in cutaneous squamous cell carcinoma (cSCC). Elevated BRD3OS (LINC00094) expression was detected in cSCC cells, and expression was downregulated by SE inhibitors THZ1 and JQ1 and via the MEK1/ERK1/2 pathway. Increased expression of BRD3OS (LINC00094) was noted in tumor cells in cSCCs and their metastases compared to normal skin, actinic keratoses, and cSCCs in situ. Higher BRD3OS (LINC00094) expression was noted in metastatic cSCCs than in non-metastatic cSCCs. RNA-seq analysis after BRD3OS (LINC00094) knockdown revealed significantly regulated GO terms Cell-matrix adhesion, Basement membrane, Metalloendopeptidase activity, and KEGG pathway Extracellular matrix-receptor interaction. Among the top-regulated genes were MMP1, MMP10, and MMP13. Knockdown of BRD3OS (LINC00094) resulted in decreased production of MMP-1 and MMP-13 by cSCC cells, suppressed invasion of cSCC cells through collagen I, and growth of human cSCC xenografts in vivo. Based on these observations, BRD3OS (LINC00094) was named SERLOC (super enhancer and ERK1/2-Regulated Long Intergenic non-protein coding transcript Overexpressed in Carcinomas). These results reveal the role of SERLOC in cSCC invasion and identify it as a potential therapeutic target in advanced cSCC.

Identification of metastatic primary cutaneous squamous cell carcinoma utilizing artificial intelligence analysis of whole slide images.

Cutaneous squamous cell carcinoma (cSCC) harbors metastatic potential and causes mortality. However, clinical assessment of metastasis risk is challenging. We approached this challenge by harnessing artificial intelligence (AI) algorithm to identify metastatic primary cSCCs. Residual neural network-architectures were trained with cross-validation to identify metastatic tumors on clinician annotated, hematoxylin and eosin-stained whole slide images representing primary non-metastatic and metastatic cSCCs (n = 104). Metastatic primary tumors were divided into two subgroups, which metastasize rapidly (≤ 180 days) (n = 22) or slowly (> 180 days) (n = 23) after primary tumor detection. Final model was able to predict whether primary tumor was non-metastatic or rapidly metastatic with slide-level area under the receiver operating characteristic curve (AUROC) of 0.747. Furthermore, risk factor (RF) model including prediction by AI, Clark's level and tumor diameter provided higher AUROC (0.917) than other RF models and predicted high 5-year disease specific survival (DSS) for patients with cSCC with 0 or 1 RFs (100% and 95.7%) and poor DSS for patients with cSCCs with 2 or 3 RFs (41.7% and 40.0%). These results indicate, that AI recognizes unknown morphological features associated with metastasis and may provide added value to clinical assessment of metastasis risk and prognosis of primary cSCC.

Retrospective, Registry-based, Cohort Investigation of Clinical Outcomes in Patients with Cutaneous Squamous Cell Carcinoma and Basal Cell Carcinoma in Finland.

Most cases of keratinocyte cancer can be treated effectively with surgery. However, survival is reduced in patients with advanced disease. This retrospective cohort study evaluated overall survival of patients with invasive keratinocyte cancers, and high-risk features for progression of the disease and mortality in Finnish patients in a real-world setting. A total of 43,143 patients with keratinocyte cancer types of basal cell carcinoma and 10,380 with cutaneous squamous cell carcinoma were identified nationwide. More detailed patient records were available for a subset of patients (basal cell carcinoma n = 5,020 and cutaneous squamous cell carcinoma n = 1,482) from a regional database. Fifty percent of patients with advanced cutaneous squamous cell carcinoma died approximately 4.5 years after diagnosis. Multivariable models suggested that risk factors for keratinocyte cancer progression were male sex, presence of comorbidities, immunosuppression, and pre-cancerous lesions, while risk factors for disease-specific mortality were advanced disease stage with immunosuppression, other malignancies, and consecutive surgical excisions. These results suggest that identifying patient and tumour factors associated with poor disease outcome could be important when determining appropriate treatment and follow-up; however, further studies are necessary.

Complement Factor D Is a Novel Biomarker and Putative Therapeutic Target in Cutaneous Squamous Cell Carcinoma.

Cutaneous squamous cell carcinoma (cSCC) is the most prevalent metastatic skin cancer. Previous studies have demonstrated the autocrine role of complement components in cSCC progression. We have investigated factor D (FD), the key enzyme of the alternative complement pathway, in the development of cSCC. RT-qPCR analysis of cSCC cell lines and normal human epidermal keratinocytes (NHEKs) demonstrated significant up-regulation of FD mRNA in cSCC cells compared to NHEKs. Western blot analysis also showed more abundant FD production by cSCC cell lines. Significantly higher FD mRNA levels were noted in cSCC tumors than in normal skin. Strong tumor cell-associated FD immunolabeling was detected in the invasive margin of human cSCC xenografts. More intense tumor cell-specific immunostaining for FD was seen in the tumor edge in primary and metastatic cSCCs, in metastases, and in recessive dystrophic epidermolysis bullosa-associated cSCCs, compared with cSCC in situ, actinic keratosis and normal skin. FD production by cSCC cells was dependent on p38 mitogen-activated protein kinase activity, and it was induced by interferon-γ and interleukin-1ß. Blocking FD activity by Danicopan inhibited activation of extracellular signal-regulated kinase 1/2 and attenuated proliferation of cSCC cells. These results identify FD as a novel putative biomarker and therapeutic target for cSCC progression.

Risk Factors and Prognosis for Metastatic Cutaneous Squamous Cell Carcinoma: A Cohort Study.

Cutaneous squamous cell carcinoma (cSCC) has metastatic potential. The aims of this study were to identify the risk factors for metastasis of primary cSCC and for poor prognosis in metastatic cSCC. Retrospective primary tumour cohorts of metastatic cSCCs (n = 85) and non-metastatic cSCCs (n = 218) were analysed. The mean annual rate of metastasis for primary cSCCs was 2.28%. In 49.4% of patients with metastatic cSCC, metastasis was detected within 6 months of diagnosis of the primary cSCC. There was no prior history of cSCC in 84.7% of metastatic cSCCs. Risk factors for metastasis included Clark's level 5, tumour diameter 20-29.9 mm, age at diagnosis < 50 or 70-79 years, and location on lower lip or forehead. A reduced risk of metastasis correlated with: isosorbide mono-/di-nitrate and/or aspirin use; comorbidity with actinic keratosis or basal cell carcinoma; and actinic keratosis or cSCC in situ as part of, or confirmedly preceding, primary cSCC. Poor prognosis in metastatic cSCC correlated significantly with ≥3 nodal metastases and extranodal extension of metastasis. These results characterize new risk factors for metastatic cSCC.