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.

Skin cancers, including basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (SCC), and melanoma, are the most common malignancies in the United States. Loss of DNA repair pathways in the skin plays a significant role in tumorigenesis. In recent years, targeting DNA repair pathways, particularly homologous recombination deficiency (HRD), has emerged as a potential therapeutic approach in cutaneous malignancies. This review provides an overview of DNA damage and repair pathways, with a focus on HRD, and discusses major advances in targeting these pathways in skin cancers. Poly(ADP-ribose) polymerase (PARP) inhibitors have been developed to exploit HRD in cancer cells. PARP inhibitors disrupt DNA repair mechanisms by inhibiting PARP enzymatic activity, leading to the accumulation of DNA damage and cell death. The concept of synthetic lethality has been demonstrated in HR-deficient cells, such as those with BRCA1/2 mutations, which exhibit increased sensitivity to PARP inhibitors. HRD assessment methods, including genomic scars, RAD51 foci formation, functional assays, and BRCA1/2 mutation analysis, are discussed as tools for identifying patients who may benefit from PARP inhibitor therapy. Furthermore, HRD has been implicated in the response to immunotherapy, and the combination of PARP inhibitors with immunotherapy has shown promising results. The frequency of HRD in melanoma ranges from 18% to 57%, and studies investigating the use of PARP inhibitors as monotherapy in melanoma are limited. Further research is warranted to explore the potential of PARP inhibition in melanoma treatment.

Circulating tumor DNA (ctDNA) is a subset of circulating cell-free DNA released by lysed tumor cells that can be characterized by its shorter strand length and tumor genome-specific information. The relatively short half-life of ctDNA allows it to provide a real-time measure of tumor burden which has potential prognostic and surveillance value as a tumor biomarker. Merkel cell carcinoma (MCC) is a rare neuroendocrine skin cancer that requires close monitoring due to the high risk of relapse. There are currently no good tumor biomarkers for MCC patients, especially those who are negative for Merkel cell polyomavirus. ctDNA shows promise for improving the prognoses of MCC patients by monitoring tumor burden, identifying minimal residual disease (MRD), and stratifying patients by their likelihood of response to immune checkpoint inhibition or risk of relapse. In particular, bespoke ultra-sequencing platforms allow for the creation of patient-specific mutation panels that improve ctDNA detection, especially for patients with rare or uncharacteristic mutations. Leveraging bespoke ctDNA assays may improve physicians’ ability to alter treatment plans for non-responsive or high-risk patients. In addition, ctDNA MRD monitoring may allow physicians to treat relapses early before clinically evident disease is present.

Effective mentorship is a pivotal factor in shaping the career trajectory of trainees interested in classical hematology (CH), which is of critical importance due to the anticipated decline in the CH workforce. However, there is a lack of mentorship opportunities within CH compared with medical oncology. To address this need, a year-long external mentorship program was implemented through the American Society of Hematology Medical Educators Institute. Thirty-five hematology/oncology fellows interested in CH and 34 academically productive faculty mentors from different institutions across North America were paired in a meticulous process that considered individual interests, experiences, and background. Pairs were expected to meet virtually once a month. Participation in a scholarly project was optional. A mixed-methods sequential explanatory design was used to evaluate the program using mentee and mentor surveys, a mentee interview, and a mentee focus group. Thirty-three mentee-mentor pairs (94.2%) completed the program. Sixty-three percent of mentee respondents worked on a scholarly project with their mentor; several mentees earned publications, grants, and awards. Mentee perception that their assigned mentor was a good match was associated with a perceived positive impact on confidence (P = .0423), career development (P = .0423), and professional identity (P = .0302). Furthermore, 23 mentees (66%) accepted CH faculty positions after fellowship. All mentor respondents believed that this program would increase retention in CH. This mentorship program demonstrates a productive, beneficial way of connecting mentees and mentors from different institutions to improve the careers of CH trainees, with the ultimate goal of increasing retention in CH.

Background/Objectives: Immune checkpoint inhibitors (ICIs) are frontline treatment for advanced Merkel Cell Carcinoma (MCC), regardless of viral status. Frontline ICIs provide durable benefit to only half of patients, highlighting a need for alternative therapies. In this study, the objective is to leverage whole exome sequencing (WES) and transcriptome sequencing (WTS) to distinguish genomic alterations associated with ICI response. Investigate differential genomic alterations between virus-positive (VP) and virus-negative (VN)-MCC to identify novel therapeutic targets. Methods: A total of 95 MCC cases underwent WES and WTS. Utilizing computational pipelines applied to WES, we identified viral status and tumor mutational burden (TMB). RNA-seq data was used to characterize the immune microenvironment. Results: Of 95 MCC cases, 57 (60%) were VP-MCC and 38 (40%) were VN-MCC. Median TMB was higher in VN-MCC (27.5 vs. 1 Muts/Mb). Mutations in TP53, RB1, NOTCH1, KMTD2, KMT2C, and PIK3CA were primarily found in VN-MCC. MAPK Pathway Activity Score, NK cell infiltration, and the immune checkpoint gene CD276 in VN-MCC tumors were upregulated. No overall survival (OS) difference was identified between VP and VN-MCC, even after ICIs. Conclusions: MCC oncogenesis and treatment response transcend viral status. While mutational analysis confirms previous findings, assessment of the transcriptome and tumor microenvironment suggests alternate therapeutic targets.

Patients diagnosed with metastatic basal cell carcinoma (BCC) have a poor prognosis. The current standard of care for adults with locally advanced or metastatic BCC who are not candidates for surgery or radiation therapy is treatment with hedgehog pathway inhibitors (HHIs). For patients who progress while on this therapy, further treatment options are limited. There is also a need for real-world clinical practice data on the clinical characteristics, management, disease progression, and survivorship of these patients. The ongoing CemiplimAb-rwlc Survivorship and Epidemiology (CASE) study is a phase IV, multicenter, prospective, noninterventional survivorship and epidemiology cohort study evaluating the effectiveness and safety of cemiplimab, a fully human immunoglobulin G4 monoclonal antibody that blocks the interaction between the programmed cell death-1 (PD-1) receptor and its ligands. This paper describes one cohort of the CASE study of patients with locally advanced or metastatic BCC who have failed or are intolerant of HHIs or for whom HHI therapy is not appropriate. Outcome measures of the study include response to treatment, quality of life, safety, treatment patterns, patient experience, and survival. This study could provide a more complete characterization of this patient population and fill knowledge gaps related to real-world treatment utilization and patient outcomes. Clinical Trial registration: NCT03836105