Epidermal Growth Factor Receptor's Function in Cutaneous Squamous Cell Carcinoma and Its Role as a Therapeutic Target in the Age of Immunotherapies

The Mutational and Microenvironmental Landscape of Cutaneous Squamous Cell Carcinoma: A Review

Cutaneous squamous cell carcinoma (cSCC) manifests through the complex interactions of UV-induced DNA damage, genetic mutations, and alterations in the tumor microenvironment. A high mutational burden is present in cSCC, as well as both cSCC precursors and normal skin, making driver genes difficult to differentiate. Despite this, several key driver genes have been identified, including TP53, the NOTCH family, CDKN2A, PIK3CA, and EGFR. In addition to mutations, the tumor microenvironment and the manipulation and evasion of the immune system play a critical role in cSCC progression. Novel therapeutic approaches, such as immunotherapy and EGFR inhibitors, have been used to target these dysregulations, and have shown promise in treating advanced cSCC cases, emphasizing the need for targeted interventions considering both genetic and microenvironmental factors for improved patient outcomes.

Therapeutic Approaches for Non-Melanoma Skin Cancer: Standard of Care and Emerging Modalities

Skin cancer encompasses a range of cutaneous malignancies, with non-melanoma skin cancers (NMSCs) being the most common neoplasm worldwide. Skin exposure is the leading risk factor for initiating NMSC. Ultraviolet (UV) light induces various genomic aberrations in both tumor-promoting and tumor-suppressing genes in epidermal cells. In conjunction with interactions with a changed stromal microenvironment and local immune suppression, these aberrations contribute to the occurrence and expansion of cancerous lesions. Surgical excision is still the most common treatment for these lesions; however, locally advanced or metastatic disease significantly increases the chances of morbidity or death. In recent years, numerous pharmacological targets were found through extensive research on the pathogenic mechanisms of NMSCs, leading to the development of novel treatments including Hedgehog pathway inhibitors for advanced and metastatic basal cell carcinoma (BCC) and PD-1/PD-L1 inhibitors for locally advanced cutaneous squamous cell carcinoma (cSCC) and Merkel cell carcinoma (MCC). Despite the efficacy of these new drugs, drug resistance and tolerability issues often arise with long-term treatment. Ongoing studies aim to identify alternative strategies with reduced adverse effects and increased tolerability. This review summarizes the current and emerging therapies used to treat NMSC.

Natural Compounds in Non-Melanoma Skin Cancer: Prevention and Treatment

The elevated occurrence of non-melanoma skin cancer (NMSC) and the adverse effects associated with available treatments adversely impact the quality of life in multiple dimensions. In connection with this, there is a necessity for alternative approaches characterized by increased tolerance and lower side effects. Natural compounds could be employed due to their safety profile and effectiveness for inflammatory and neoplastic skin diseases. These anti-cancer drugs are often derived from natural sources such as marine, zoonotic, and botanical origins. Natural compounds should exhibit anti-carcinogenic actions through various pathways, influencing apoptosis potentiation, cell proliferation inhibition, and metastasis suppression. This review provides an overview of natural compounds used in cancer chemotherapies, chemoprevention, and promotion of skin regeneration, including polyphenolic compounds, flavonoids, vitamins, alkaloids, terpenoids, isothiocyanates, cannabinoids, carotenoids, and ceramides.

Recruitment of hexahydroquinoline as anticancer scaffold targeting inhibition of wild and mutants EGFR (EGFRWT, EGFRT790M, and EGFRL858R)

Hexahydroquinoline (HHQ) scaffold was constructed and recruited for development of new series of anticancer agents. Thirty-two new compounds were synthesised where x-ray crystallography was performed to confirm enantiomerism. Thirteen compounds showed moderate to good activity against NCI 60 cancer cell lines, with GI % mean up to 74% for 10c. Expending erlotinib as a reference drug, target compounds were verified for their inhibiting activities against EGFRWT, EGFRT790M, and EGFRL858R where compound 10d was the best inhibitor with IC50 = 0.097, 0.280, and 0.051 µM, respectively, compared to erlotinib (IC50 = 0.082 µM, 0.342 µM, and 0.055 µM, respectively). Safety profile was validated using normal human lung (IMR-90) cells. 10c and 10d disrupted cell cycle at pre-G1 and G2/M phases in lung cancer, HOP-92, and cell line. Molecular docking study was achieved to understand the potential binding interactions and affinities in the active sites of three versions of EGFRs.

Proline-rich 11 (PRR11) promotes the progression of cutaneous squamous cell carcinoma by activating the EGFR signaling pathway

Cutaneous squamous cell carcinoma (cSCC) is one of the most common skin malignancies, and its incidence rate is increasing worldwide. Proline-rich 11 (PRR11) has been reported to be involved in the occurrence and development of various tumors. However, the role of PRR11 in cSCC remains unknown. In the present study, we observed upregulated expression of PRR11 in cSCC tissues and cell lines. Knockdown of PRR11 in the cSCC cell lines A431 and SCL-1 inhibited cell proliferation by inducing cell cycle arrest during the G1/S phase transition, promoted cell apoptosis, and reduced cell migration and invasion in vitro. Conversely, overexpression of PRR11 promoted cell proliferation, decreased cell apoptosis, and enhanced cell migration and invasion. PRR11 knockdown also inhibited cSCC tumor growth in a mouse xenograft model. Mechanistic investigations by RNA sequencing revealed that 891 genes were differentially expressed genes between cells with PRR11 knockdown and control cells. Enrichment analysis of different genes showed that the epidermal growth factor receptor (EGFR) signaling pathway was the top enriched pathway. We further validated that PRR11 induced EGFR pathway activity, which contributed to cSCC progression. These data suggest that PRR11 may serve as a novel therapeutic target in cSCC.

Molecular Mechanisms of Cutaneous Squamous Cell Carcinoma

Non-melanoma skin cancers are cutaneous malignancies representing the most common form of cancer in the United States. They are comprised predominantly of basal cell carcinomas and squamous cell carcinomas (cSCC). The incidence of cSCC is increasing, resulting in substantial morbidity and ever higher treatment costs; currently in excess of one billion dollars, per annum. Here, we review research defining the molecular basis and development of cSCC that aims to provide new insights into pathogenesis and drive the development of novel, cost and morbidity saving therapies.

Survival after parotid gland metastases of cutaneous squamous cell carcinoma of the head and neck

Purpose

Malignant tumours in the parotid gland can originate either from the gland itself or as a result of metastatic spread of other tumours, such as cutaneous squamous cell carcinomas (CSCC) of the head and neck area. The aim of this study was to analyse and compare the clinical behaviour of primary as well as CSCC metastatic parotid cancers with special emphasis on therapy and oncologic outcome.

Methods

Clinical and histopathological data of 342 patients with parotid gland malignomas surgically treated in a tertiary referral centre between 1987 and 2015 were retrospectively assessed. Oncologic outcomes of all cases with CSCC metastasis of the parotid gland (n = 49) were compared to those of primary parotid gland carcinomas (n = 293).

Results

Mean age at diagnosis was 72.3 years for CSCC patients versus 56.8 years in patients with primary parotid carcinoma. A total of 83.7% of CSCC patients were male, compared to 48.8% in the group of primary carcinomas. Forty-five out of 49 CSCC patients underwent total parotidectomy and neck dissection (91.8%). A total of 93.9% out of all CSCC patients received adjuvant radiotherapy. Five-year overall survival (OS) was 32.6% in CSCC patients versus 77.2% in primary parotid carcinoma patients.

Conclusion

As compared to primary parotid cancers, we could show that patients suffering from CSCC metastases to the parotid gland presented with significantly higher age and worse survival.

Deciphering the Molecular Landscape of Cutaneous Squamous Cell Carcinoma for Better Diagnosis and Treatment

Cutaneous squamous cell carcinoma (cSCC) is a common type of neoplasia, representing a terrible burden on patients' life and clinical management. Although it seldom metastasizes, and most cases can be effectively treated with surgical intervention, once metastatic cSCC displays considerable aggressiveness leading to the death of affected individuals. No consensus has been reached as to which features better characterize the aggressive behavior of cSCC, an achievement hindered by the high mutational burden caused by chronic ultraviolet light exposure. Even though some subtypes have been recognized as high risk variants, depending on certain tumor features, cSCC that are normally thought of as low risk could pose an increased danger to the patients. In light of this, specific genetic and epigenetic markers for cutaneous SCC, which could serve as reliable diagnostic markers and possible targets for novel treatment development, have been searched for. This review aims to give an overview of the mutational landscape of cSCC, pointing out established biomarkers, as well as novel candidates, and future possible molecular therapies for cSCC.