Immunotherapy for Cutaneous Squamous Cell Carcinoma: Results and Perspectives

Evaluation of Clinical Parameters Associated with Response and Resistance to Cemiplimab in Locally Advanced and Metastatic Cutaneous Squamous Cell Carcinoma: A Multi-Institutional Retrospective Cohort Study

Cutaneous squamous cell carcinoma (cSCC) is a common cancer with increasing incidence and 5% of patients develop incurable disease, often resistant to chemotherapy. The anti-PD-1 therapy cemiplimab has shown high efficacy in clinical trials. This retrospective study evaluated the real-world effectiveness of cemiplimab in incurable cSCC and examined factors influencing response and toxicity. Data from 86 patients across three UK healthcare providers were analysed. Median progression-free survival (PFS) and overall survival (OS) were not reached, with 38% showing durable responses beyond 12 months. The overall response rate was 60.8% (95% CI 49-71), and the clinical benefit rate was 74.3% (95% CI 63-83). A head and neck primary site was associated with improved PFS (p = 0.008) and OS (p = 0.023), while concurrent immunosuppression was associated with worse PFS (p < 0.001). These findings align with clinical trials, suggesting cemiplimab is effective and safe in the recurrent/metastatic setting.

Self-delivering RNAi immunotherapeutic PH-762 silences PD-1 to generate local and abscopal antitumor efficacy

Objective

Immunotherapeutic inhibition of PD-1 by systemically administered monoclonal antibodies is widely used in cancer treatment, but it may cause severe immune-related adverse events (irSAEs). Neoadjuvant PD-1 inhibition before surgery has shown promise in reducing recurrence by stimulating durable antitumor immunity. Local intratumoral (IT) immunotherapy is a potential strategy to minimize irSAEs, but antibodies have limited tumor penetration, making them less suitable for this approach. Therapeutic self-delivering RNAi (INTASYL) is an emerging modality well-suited for neoadjuvant immunotherapy. This study presents preclinical proof-of-concept for PH-762, an INTASYL designed to silence PD-1, currently in clinical development for advanced cutaneous malignancies (ClinicalTrials.gov#NCT06014086).

Methods and analysis

PH-762 pharmacology was characterized in vitro, and in vivo antitumor efficacy was evaluated using a murine analogue (mPH-762) in syngeneic tumor models with varying PD-1 responsiveness. Bilateral Hepa1-6 models assessed abscopal effects of local treatment. Ex vivo analyses explored mechanisms of direct and abscopal efficacy.

Results

PH-762 was rapidly internalized by human T cells, silencing PD-1 mRNA and decreasing PD-1 surface protein, enhancing TCR-stimulated IFN-γ and CXCL10 secretion. In vivo, IT mPH-762 provided robust antitumor efficacy, local and lymphatic biodistribution, and was well tolerated. Ex vivo analyses revealed that IT mPH-762 depleted PD-1 protein, promoted leukocyte and T cell infiltration, and correlated with tumor control. IT mPH-762 also demonstrated efficacy against untreated distal tumors (abscopal effect) by priming systemic antitumor immunity.

Conclusion

These data support PH-762 as a promising candidate for neoadjuvant immunotherapy in clinical studies.

Immune Checkpoint Inhibitor Therapy for Kidney Transplant Recipients - A Review of Potential Complications and Management Strategies

Immune checkpoint inhibitor (ICI) therapy has enabled a paradigm shift in Oncology, with the treatment of metastatic cancer in certain tumor types becoming akin to the treatment of chronic disease. Kidney transplant recipients (KTR) are at increased risk of developing cancer compared to the general population. Historically, KTR were excluded from ICI clinical trials due to concern for allograft rejection and decreased anti-tumor efficacy. While early post-marketing data revealed an allograft rejection risk of 40%-50%, 2 recent small prospective trials have demonstrated lower rates of rejection of 0%-12%, suggesting that maintenance immunosuppression modification prior to ICI start modulates rejection risk. Moreover, objective response rates induced by ICI for the treatment of advanced or metastatic skin cancer, the most common malignancy in KTR, have been comparable to those achieved by immune intact patients. Non-invasive biomarkers may have a role in risk-stratifying patients before starting ICI, and monitoring for rejection, though allograft biopsy is required to confirm diagnosis. This clinically focused review summarizes current knowledge on complications of ICI use in KTR, including their mechanism, risk mitigation strategies, non-invasive biomarker use, approaches to treatment of rejection, and suggestions for future directions in research.

Case report: Neoadjuvant-intent pembrolizumab resulted in complete response in a xeroderma pigmentosum patient with locally advanced resectable cutaneous squamous cell carcinoma of the nose

Background

Anti-PD1 antibodies have gained popularity in the treatment of skin cancers. These drugs have been FDA approved for treatment of cutaneous melanoma and unresectable/metastatic squamous cell carcinoma of the skin. However, the use of anti-PD1 antibodies is not established for resectable cutaneous squamous cell carcinoma, as the mainstay treatment is surgical excision.

Case

A 49-year-old female with Xeroderma Pigmentosum presented with an ulcerating lateral nasal mass causing obstruction. Biopsy confirmed cutaneous squamous cell carcinoma and was staged as IVA (T2N2cM0) based on PET-CT findings, which showed a 2.7 × 2.3 cm left nasal mass and radiotracer-avid cervical lymph nodes. Despite surgical recommendations, the patient declined surgery due the expected morbidity and disfigurement. Instead, she received neoadjuvant Pembrolizumab (200 mg IV every 3 weeks). After two cycles, PET-CT and MRI showed significant reduction in the nasal mass and decreased cervical lymph node involvement. On physical exam, the nasal lesion had resolved. Multidisciplinary tumor board discussion recommended radiation therapy instead of neck dissection, considering the patient's clinical response and potential surgical morbidity. After a third Pembrolizumab cycle, she received 66 Gy in 33 fractions, followed by continued adjuvant immunotherapy.

Evidence of Neutrophils and Neutrophil Extracellular Traps in Human NMSC with Regard to Clinical Risk Factors, Ulceration and CD8+ T Cell Infiltrate

Non-melanoma skin cancers (NMSC), including basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC), and Merkel cell carcinoma (MCC), are increasingly common and present significant healthcare challenges. Neutrophil extracellular traps (NETs), chromatin fibers expulsed by neutrophil granulocytes, can promote immunotherapy resistance via an impairment of CD8+ T cell-mediated cytotoxicity. Here, to identify a potential therapeutic target, we investigate the expulsion of NETs and their relation to CD8+ T cell infiltration in NMSC. Immunofluorescence staining for neutrophils (CD15) and NETs (H3cit), as well as immunohistochemistry for cytotoxic T cells (CD8+) on human cSCCs (n = 24), BCCs (n = 17) and MCCs (n = 12), revealed a correlation between neutrophil infiltration and ulceration diameter in BCC and MCC, but not in cSCC. In BCC and cSCC, neutrophil infiltration also correlated with the cross-sectional area (CSA). NETs were not associated with established risk factors but with the presence of an ulceration, and, in cSCC, with abscess-like structures. CD8+ T cell infiltration was not reduced in tumors that were NET-positive nor in those with a denser neutrophil infiltration. This study is the first to report and characterize NETs in NMSC. Thus, it gives an incentive for further research in this relevant yet understudied topic.

Immune Checkpoints and Cellular Landscape of the Tumor Microenvironment in Non-Melanoma Skin Cancer (NMSC)

Non-melanoma skin cancer (NMSC) is primarily categorized into basal cell carcinoma (BCC), the most prevalent form of skin cancer, and cutaneous squamous cell carcinoma (cSCC), the second most common type. Both BCC and cSCC represent a significant health burden, particularly in immunocompromised individuals and the elderly. The immune system plays a pivotal role in the development and progression of NMSC, making it a critical focus for therapeutic interventions. This review highlights key immunological targets in BCC and cSCC, with a focus on immune checkpoint molecules such as PD-1/PD-L1 and CTLA-4, which regulate T cell activity and contribute to immune evasion. This review also highlights anti-tumor immune cell subsets within the tumor microenvironment (TME), such as tumor-infiltrating lymphocytes (TILs) and dendritic cells. Additionally, it examines the immunosuppressive elements of the TME, including regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and cancer-associated fibroblasts (CAFs), as well as their roles in NMSC progression and resistance to therapy. Emerging strategies targeting these immune elements, such as monoclonal antibodies, are also discussed for their potential to enhance anti-tumor immune responses and improve clinical outcomes. By elucidating the immunological landscape of BCC and cSCC and drawing comparisons to melanoma, this review highlights the transformative potential of immunotherapy in treating these malignancies.

Systemic Therapy for Non-Melanoma Skin Cancers: Latest Advances

PURPOSE OF REVIEW

This review provides an update on approved and emerging systemic therapies in the treatment of locally advanced or metastatic non-melanoma skin cancers (squamous cell carcinoma, basal cell carcinoma, Merkel cell carcinoma).

RECENT FINDINGS

Many studies demonstrate the effectiveness of immunotherapy for all types of non-melanoma skin cancer. For basal cell carcinoma (BCC), hedgehog inhibitors (HHI) remain first-line but with poor tolerability. Numerous clinical trials studying both neoadjuvant and adjuvant use of anti-PD-1 and anti-PD-L1 therapies in advanced NMSC are under investigation. There is a growing number of systemic therapies available to treat non-melanoma skin cancers. The advent of immunotherapy has revolutionized the field and greatly improved survival compared to historical survival rates with cytotoxic chemotherapy.

Rapid Life-Saving Response to Anti-PD-1 in a Solid Organ Transplant Recipient With Metastatic Cutaneous Squamous Cell Carcinoma: A Case Report and Review

SUMMARY

Anti-programmed cell death protein 1 (PD-1) therapy is considered effective in the treatment of metastatic or locally advanced cutaneous squamous cell carcinoma but the use of these agents in solid organ transplant recipients (SOTRs) is often taken with caution. While anti-tumor effects without graft rejection have been reported, studies have shown high rates of fatal graft rejection with immune checkpoint therapy. In this case report, we present an SOTR patient with life-threatening, acute hypoxic respiratory failure due to rapidly progressive metastatic cutaneous squamous cell carcinoma with lung and pleural involvement. Modification of their immunosuppressive regimen and treatment with front-line anti-PD-1 inhibitor, pembrolizumab, led to rapid clinical response with near complete resolution of metastatic pulmonary disease and no long-term evidence of graft rejection. Our case report shows that front-line treatment with PD-1 inhibitors can be safely administered in SOTR patients with rapid metastatic disease control.

Surgical Management of Patients with Parotid Involvement from Non-Melanoma Skin Cancer of the Head and Neck

We conducted a retrospective, longitudinal study on a single-center series of patients who underwent parotidectomy in the management of advanced head and neck non-melanoma skin cancer (hnNMSC). The aim of this study was to identify prognostic factors associated with worse outcomes. Forty-one men and nine women were included. The mean age at the time of surgery was 78.9 years. The 5-year overall survival, disease-specific survival, locoregional recurrence-free survival, and distant metastasis-free survival calculated with Kaplan-Meier curves were 39.9%, 56.3%, 58.6%, and 82.1%, respectively. A univariate analysis showed that the status of the margins, facial nerve direct involvement, lymph vascular invasion, and histological grading were associated with worse outcomes (p < 0.05). Positive margins were associated with worse disease-specific survival also in a multivariate analysis (p = 0.001, HR = 32.02, and CIs 4.338 to 351.3). Because the resection in free margins is the most important prognostic factor, early diagnosis or, in the case of advanced disease, extensive surgical resection with concomitant reconstruction is needed. Adjuvant therapy is indicated in selected cases.

Differential Immunoexpression of Inhibitory Immune Checkpoint Molecules and Clinicopathological Correlates in Keratoacanthoma, Primary Cutaneous Squamous Cell Carcinoma and Metastases

Beyond established anti-programmed cell death protein 1/programmed cell death ligand 1 immunotherapy, T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domain (TIGIT) and its ligand CD155 are promising novel inhibitory immune checkpoint targets in human malignancies. Yet, in cutaneous squamous cell carcinoma, evidence on the collective expression patterns of these inhibitory immune checkpoints is scarce. Complete tumour sections of 36 cutaneous squamous cell carcinoma, 5 cutaneous metastases and 9 keratoacanthomas, a highly-differentiated, squamoproliferative tumour, with disparately benign biologic behaviour, were evaluated by immunohistochemistry for expression of programmed cell death ligand 1 (Tumor Proportion Score, Immune Cell Score), TIGIT, CD155 and CD8+ immune infiltrates. Unlike keratoacanthomas, cutaneous squamous cell carcinoma displayed a strong positive correlation of programmed cell death ligand 1 Tumor Proportion Score and CD115 expression (p < 0.001) with significantly higher programmed cell death ligand 1 Tumor Proportion Score (p < 0.001) and CD155 expression (p < 0.01) in poorly differentiated G3-cutaneous squamous cell carcinoma compared with keratoacanthomas. TIGIT+ infiltrates were significantly increased in programmed cell death ligand 1 Immune Cell Score positive primary tumours (p = 0.05). Yet, a strong positive correlation of TIGIT expression with CD8+ infiltrates was only detected in cutaneous squamous cell carcinoma (p < 0.01), but not keratoacanthomas. Providing a comprehensive overview on the collective landscape of inhibitory immune checkpoint expression, this study reveals associations of novel inhibitory immune checkpoint with CD8+ immune infiltrates and tumour differentiation and highlights the TIGIT/CD155 axis as a potential new target for cutaneous squamous cell carcinoma immunotherapy.

Favorable efficacy of S-1 treatment for locoregionally advanced cutaneous squamous cell carcinoma in the head and neck region

Cutaneous squamous cell carcinoma is usually treated with surgery; however, locoregionally advanced cutaneous squamous cell carcinoma can be difficult to resect. Although recent guidelines from Western countries recommend using anti-programmed cell death protein 1 (PD-1) antibodies, including cemiplimab and pembrolizumab, there are no approved anti-PD-1 antibodies for locoregional cutaneous squamous cell carcinoma in Asian countries. S-1 is an oral drug with a low incidence of severe toxicity that can be used for head and neck cancers, including head and neck locoregional cutaneous squamous cell carcinoma, in Japan. We retrospectively evaluated patients with head and neck locoregional cutaneous squamous cell carcinoma treated with S-1 at two Japanese institutions (2008-2022). The initial dosage was determined by the body surface area (<1.25 m2 : 80 mg/day, 1.25-1.5 m2 : 100 mg/day, ≥1.5 m2: 120 mg/day) for 28 consecutive days. The outcome measures were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Fourteen patients were included. The ORR was 78%, and the complete response (CR) rate was 64.3%. The median PFS and OS were not reached (NR) (95% confidence interval [CI], 5.9 months-NR) and NR (95% CI, 13.8 months-NR), respectively. The 12-month PFS and OS rates were 51% and 85%, respectively. Six of the nine patients who achieved CR showed no recurrence during the follow-up period (median follow-up, 24.7 months). After CR, three patients experienced recurrence. Among these, two resumed S-1 treatment and subsequently underwent salvage surgery, resulting in a sustained absence of recurrence. One patient developed lung metastasis and died, although S-1 therapy was resumed. Only one patient (7.1%) developed grade 3 anemia. S-1 showed favorable efficacy and low toxicity in patients with head and neck locoregionally advanced cutaneous squamous cell carcinoma. S-1 may be a good alternative to the anti-PD-1 antibody for treating head and neck locoregionally advanced squamous cell carcinoma.

Atypical Site of Presentation of a Rare Type of SMARCA4-Positive Cutaneous Squamous Cell Carcinoma of the Skin: Case Report and Review of the Literature

Cutaneous squamous cell carcinoma (cSCC) comprises 20% of cases of nonmelanoma skin cancers in the United States. In total, 3% to 5% of squamous cell carcinoma (SCC) are metastatic at the time of presentation, associated with significant mortality due to a lack of standardized treatment options. In total, 95% of these tumors are amenable to the initial standard of treatment, which is surgical resection. However, a small percentage of them require systemic therapy as they are either locally advanced to regional lymph nodes or have distant metastasis. The common sites of presentation of cSCC are the scalp and the face with predictable spread to the intra-parotid, upper jugular, and perifacial lymph nodes. In our case report, however, our patient had a large lump lesion on the upper back, an unusual site of presentation of cSCC, with locally advanced metastasis to the left axillary lymph nodes. Subsequently, the tumor marker study revealed a positive SMARCA4 variant (the essential ATPase subunit of the Switch (SWI)/Sucrose Nonfermenting (SNF) chromatin-remodeling complex) that is even rarer in the context of cSCC. Furthermore, abnormalities in SWI/SNF chromatin-remodeling complex subunits have shown promising results as a target therapy for immune checkpoint inhibitor (ICI) therapy. We present an atypical presentation site of locally advanced rare variant SMARCA4-positive cSCC in a patient who received treatment with chemoradiation and systemic therapy with ICI after primary surgical resection. To date, only 2 cases of SMARCA4-positive cSCC were found in the literature with no details of the treatment received. Our case is unique in its atypical site of presentation as well as showing partial response to radiotherapy (RT) and systemic therapy with ICI.

Nivolumab for locally advanced and metastatic cutaneous squamous cell carcinoma (NIVOSQUACS study)-Phase II data covering impact of concomitant haematological malignancies

BACKGROUND

Monoclonal antibodies, such as cemiplimab and pembrolizumab, against the programmed death receptor (PD)-1 have become the current standard of care and first-line treatment of advanced cutaneous squamous cell carcinoma (cSCC), proving remarkable clinical benefit and acceptable safety.

OBJECTIVES

To assess efficacy and safety of the anti-PD-1 antibody nivolumab in patients with locally advanced and metastatic cSCC.

METHODS

Patients received open-label nivolumab 240 mg intravenously every 2 weeks for up to 24 months. Patients with concomitant haematological malignancies (CHMs), either non-progressing or stable under active therapy, were eligible for inclusion.

RESULTS

Of 31 patients with a median age of 80 years, 22.6% of patients achieved an investigator assessed complete response, resulting in an objective response rate (ORR) of 61.3% and a disease control rate (DCR) of 64.5%. Progression-free survival (PFS) was 11.1 months, and the median overall survival (OS) was not reached after 24 weeks of therapy. Median follow-up was 23.82 months. Subgroup analysis of the CHM cohort (n = 11; 35%) revealed an ORR of 45.5%, a DCR of 54.5%, a median PFS of 10.9 months, and median OS of 20.7 months. Treatment related adverse events were reported in 58.1% of all patients (19.4% grade 3, the remaining grade 1 or 2). PD-L1 expression and CD-8+ T-cell infiltration did not significantly correlate with clinical response, although a trend towards a shorter PFS of 5.6 months was observed with PD-L1 negativity and low CD8+ intratumoral infiltration.

CONCLUSION

This study demonstrated robust clinical efficacy of nivolumab in patients with locally advanced and metastatic cSCCs and a tolerability comparable to data of other anti-PD-1 antibodies. Favourable outcomes were obtained despite involving the oldest hitherto reported study cohort for anti-PD-1 antibodies and a significant proportion of CHM patients prone to high risk tumours and an aggressive course otherwise typically excluded from clinical trials.

Immunotherapy response in patients with cutaneous squamous cell carcinoma of head and neck with cranial nerve involvement

BACKGROUND

Metastatic or locally advanced cutaneous squamous cell carcinoma (cSCC) can be treated with immunotherapy (IO). Cranial nerve involvement (CNI) is uncommon in cSCC and is a poor prognostic factor. Our aim is to describe how patients with CNI respond to IO monotherapy and/or as an adjunct to RT.

METHODS

Under an IRB approved protocol, patients with histologically proven cSCC of the head and neck with CNI treated with IO were retrospectively reviewed.

RESULTS

Twelve patients were included and received cemiplimab or pembrolizumab. Eight patients had CNI at diagnosis, and 4 at time of recurrence after non-IO therapy. Best responses were complete response (1), partial response (7), stable disease (1), progressive disease (2), and pending response (1). Nine patients are alive, 6 of which remain on IO.

CONCLUSIONS

In this cohort, IO showed clinical response in 83% of patients, indicating IO can be an effective monotherapy, reserving RT for instances of local failure after IO.

Cancer Vaccines: From the State of the Art to the Most Promising Frontiers in the Treatment of Colorectal Cancer

Colorectal cancer represents 10% of all new cancer cases each year and accounts for almost 10% of all cancer deaths. According to the WHO, by 2040 there will be a 60% increase in colorectal cancer cases. These data highlight the need to explore new therapeutic strategies. Classical interventions include surgical resection, chemotherapy and radiotherapy, which are invasive strategies that have many side effects on the patients and greatly affect their quality of life. A great advance in the treatment of this cancer type, as well as of all the others, could be the development of a vaccination strategy preventing the onset, the progression or the relapse of the pathology. In this review, we summarize the main vaccination strategies that are being studied for the treatment of colorectal cancer (CRC) and finally explore the possibility of using B-cells for the development of a new type of vaccine.

Update on the Molecular Pathology of Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer, originating from keratinocytes of the spinous layer. Numerous risk factors have been discovered for the initiation and growth of this type of cancer, such as exposure to UV and ionizing radiation, chemical carcinogens, the presence of immunosuppression states, chronic inflammation, infections with high-risk viral strains, and, last but not least, the presence of diseases associated with genetic alterations. The important socio-economic impact, as well as the difficulty associated with therapy for advanced forms, has made the molecular mechanisms underlying this neoplasia more and more intensively studied, with the intention of achieving a better understanding and advancing the treatment of this pathology. This review aims to provide a brief foray into the molecular, genetic, and epigenetic aspects of this cancer, as well as the treatment methods, ranging from the first used to the latest targeted therapies.

Understanding the squamous cell carcinoma immune microenvironment

Primary cutaneous squamous cell carcinoma (cSCC) is the second most common human cancer with a rising incidence of about 1.8 million in the United States annually. Primary cSCC is usually curable by surgery; however, in some cases, cSCC eventuates in nodal metastasis and death from disease specific death. cSCC results in up to 15,000 deaths each year in the United States. Until recently, non-surgical options for treatment of locally advanced or metastatic cSCC were largely ineffective. With the advent of checkpoint inhibitor immunotherapy, including cemiplimab and pembrolizumab, response rates climbed to 50%, representing a vast improvement over chemotherapeutic agents used previously. Herein, we discuss the phenotype and function of SCC associated Langerhans cells, dendritic cells, macrophages, myeloid derived suppressor cells and T cells as well as SCC-associated lymphatics and blood vessels. Possible role(s) of SCC-associated cytokines in progression and invasion are reviewed. We also discuss the SCC immune microenvironment in the context of currently available and pipeline therapeutics.

Review: PD-L1 as an emerging target in the treatment and prevention of keratinocytic skin cancer

Recent advances in the understanding and targeting of immune checkpoints have led to great progress in immune therapies against many forms of cancer. While many types of immune checkpoints are currently targeted in the clinic, this review will focus on recent research implicating the programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) axis as an emerging focus for the treatment of keratinocytic tumors. PD-L1 is of particular interest in nonmelanoma skin cancer (NMSC), as it is not only upregulated in these tumors but is stimulated by environmental ultraviolet exposure. This response may also make PD-L1 an excellent target for photochemoprevention using topically applied small molecule inhibitors. Here, we summarize recent investigations on PD-L1 expression and clinically relevant immune checkpoint inhibitor treatment in cutaneous squamous cell carcinoma, basal cell carcinoma, and head and neck squamous cell carcinoma, as well as small molecule agents targeting PD-L1 that may be useful for clinical development aiming at treatment or prevention of NMSC.

Recent Advances in Immunotherapy for Patients with Head and Neck Cutaneous Squamous Cell Carcinoma

Simple Summary

Cutaneous squamous cell cancer is a form of skin cancer, which is typically found in older fair-skinned individuals with frequent sun exposure. Most patients present with limited disease and can be treated with a combination of surgery and/or radiation with favorable outcomes. A small percentage of patients present with more aggressive, widespread disease. Immunotherapy has dramatically improved outcomes and has become the preferred treatment option for these patients. In this review article, the rationale for using immunotherapy in patients with squamous cell skin cancer is discussed. A summary of the new treatment options currently being explored is also provided.

Abstract

Cutaneous squamous cell carcinoma (CSCC) is the second most common non-melanoma skin cancer. A majority of patients present with localized disease, but some can present with locally advanced or metastatic disease. Most of these advanced cases occur in the anatomical head and neck region and are associated with more aggressive disease, necessitating prompt and effective treatment. Prior to the emergence of immunotherapy, systemic treatment options were limited to platinum-based chemotherapy and salvaged with targeted epidermal growth factor therapy. These therapies were associated with poor efficacy and increased toxicity in an often frail, older population. Immunotherapy has dramatically improved outcomes in this patient population due to its favorable side effect profile, durable treatment response, and improved overall outcomes. In this review, an overview of the recent advances of immunotherapy in the management of CSCC in the anatomical head and neck region is provided, with a focus on advanced presentations.

Dermatologic Disease-Directed Targeted Therapy (D3T2): The Application of Biomarker-Based Precision Medicine for the Personalized Treatment of Skin Conditions-Precision Dermatology

Precision dermatology uses individualized dermatologic disease-directed targeted therapy (D3T2) for the management of dermatoses and for the evaluation and therapy of cutaneous malignancies. Personalized/precision strategies are based on biomarkers that are most frequently derived from tissue transcriptomic expression or genomic sequencing or from circulating cytokines. For instance, the pathologic diagnosis of a pigmented lesion and determining the prognosis of a malignant melanocytic neoplasm can be enhanced by genomic/transcriptomic analysis. In addition to biopsy, innovative techniques have been developed for obtaining transcriptomes in skin conditions; as an example, patches can be applied to a psoriasis plaque for a few minutes to capture the epidermis/upper dermis transcriptome. Atopic dermatitis and prurigo nodularis may also be candidate conditions for precision dermatology. Precision dermatology has a role in managing melanoma and nonmelanoma skin cancers and rare cutaneous tumors-such as perivascular epithelioid cell tumor (PEComa)-that can originate in or metastasize to the skin. For instance, advanced/metastatic basal cell carcinomas can be treated with Hedgehog inhibitors (vismodegib and sonidegib) targeting the smoothened (SMO) or patched 1 (PTCH1) gene alterations that are a hallmark of these cancers and activate the Hedgehog pathway. Advanced/metastatic basal and cutaneous squamous cell cancers often have a high tumor mutational burden (which predicts immunotherapy response); immune checkpoint blockade with cemiplimab, a programmed cell death protein 1 (PD1) inhibitor, is now approved for these malignancies. Gene expression profiling of primary cutaneous squamous cell carcinoma can identify those individuals at high risk for subsequent metastases. In the realm of rare neoplasms, PEComas-which can originate in the skin, albeit uncommonly-have tuberous sclerosis complex 1 (TSC1)/tuberous sclerosis complex 2 (TSC2) gene alterations, which activate mammalian target of rapamycin (mTOR) signaling, and can be suppressed by nab-sirolimus, now approved for this condition. In summary, precision dermatologic techniques/strategies are an important emerging approach for evaluation and management of skin disorders and cutaneous neoplasms, and may serve as a paradigm for the application of precision medicine beyond dermatology.

Immunotherapy for the Treatment of Squamous Cell Carcinoma: Potential Benefits and Challenges

Melanoma and nonmelanoma skin cancers (NMSCs) are recognized as among the most common neoplasms, mostly in white people, with an increasing incidence rate. Among the NMSCs, squamous cell carcinoma (SCC) is the most prevalent malignancy known to affect people with a fair complexion who are exposed to extreme ultraviolet radiation (UVR), have a hereditary predisposition, or are immunosuppressed. There are several extrinsic and intrinsic determinants that contribute to the pathophysiology of the SCC. The therapeutic modalities depend on the SCC stages, from actinic keratosis to late-stage multiple metastases. Standard treatments include surgical excision, radiotherapy, and chemotherapy. As SCC represents a favorable tumor microenvironment with high tumor mutational burden, infiltration of immune cells, and expression of immune checkpoints, the SCC tumors are highly responsive to immunotherapies. Until now, there are three checkpoint inhibitors, cemiplimab, pembrolizumab, and nivolumab, that are approved for the treatment of advanced, recurrent, or metastatic SCC patients in the United States. Immunotherapy possesses significant therapeutic benefits for patients with metastatic or locally advanced tumors not eligible for surgery or radiotherapy to avoid the potential toxicity caused by the chemotherapies. Despite the high tolerability and efficiency, the existence of some challenges has been revealed such as, resistance to immunotherapy, less availability of the biomarkers, and difficulty in appropriate patient selection. This review aims to accumulate evidence regarding the genetic alterations related to SCC, the factors that contribute to the potential benefits of immunotherapy, and the challenges to follow this treatment regime.

Skin Cancer Research Goes Digital: Looking for Biomarkers within the Droplets

Skin cancer, which includes the most frequent malignant non-melanoma carcinomas (basal cell carcinoma, BCC, and squamous cell carcinoma, SCC), along with the difficult to treat cutaneous melanoma (CM), pose important worldwide issues for the health care system. Despite the improved anti-cancer armamentarium and the latest scientific achievements, many skin cancer patients fail to respond to therapies, due to the remarkable heterogeneity of cutaneous tumors, calling for even more sophisticated biomarker discovery and patient monitoring approaches. Droplet digital polymerase chain reaction (ddPCR), a robust method for detecting and quantifying low-abundance nucleic acids, has recently emerged as a powerful technology for skin cancer analysis in tissue and liquid biopsies (LBs). The ddPCR method, being capable of analyzing various biological samples, has proved to be efficient in studying variations in gene sequences, including copy number variations (CNVs) and point mutations, DNA methylation, circulatory miRNome, and transcriptome dynamics. Moreover, ddPCR can be designed as a dynamic platform for individualized cancer detection and monitoring therapy efficacy. Here, we present the latest scientific studies applying ddPCR in dermato-oncology, highlighting the potential of this technology for skin cancer biomarker discovery and validation in the context of personalized medicine. The benefits and challenges associated with ddPCR implementation in the clinical setting, mainly when analyzing LBs, are also discussed.

PET-CT in Clinical Adult Oncology-VI. Primary Cutaneous Cancer, Sarcomas and Neuroendocrine Tumors

PET-CT is an advanced imaging modality with many oncologic applications, including staging, therapeutic assessment, restaging and surveillance for recurrence. The goal of this series of six review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for specific oncologic indications, the potential pitfalls and nuances that characterize these applications, and guidelines for image interpretation. Tumor-specific clinical information and representative PET-CT images are provided. The current, sixth article in this series addresses PET-CT in an evaluation of aggressive cutaneous malignancies, sarcomas and neuroendocrine tumors. A discussion of the role of FDG PET for all types of tumors in these categories is beyond the scope of this review. Rather, this article focuses on the most common malignancies in adult patients encountered in clinical practice. It also focuses on Food and Drug Agency (FDA)-approved and clinically available radiopharmaceuticals rather than research tracers or those requiring a local cyclotron. This information will serve as a guide to primary providers for the appropriate role of PET-CT in managing patients with cutaneous malignancies, sarcomas and neuroendocrine tumors. The nuances of PET-CT interpretation as a practical guide for imaging providers, including radiologists, nuclear medicine physicians and their trainees, are also addressed.