Summary of all MCPyV Indel calls in VP-MCC tumors.

Merkel cell carcinoma (MCC) is an aggressive disease with poor survival outcomes and increasing incidence. There is a clear and present need for enhanced understanding of cellular mechanisms of tumorigenesis, validation of robust genetic signatures predictive of aggressive disease, and novel informatics tools to simplify analysis of Merkel cell polyomavirus (MCPyV)-host genome interactions. Genomic DNA was harvested from 54 MCC tumors for exome sequencing and in-depth genetic profiling of a 226-gene panel. We further developed a robust informatics package (MCPyViewer) optimized for MCPyV integration site analysis with graphical output to simplify usability for end users. Finally, we assessed the prognostic impact of specific genetic signatures on MCC-specific survival in our cohort. Our study included 54 patients (n = 44 MCPyV positive), 11 (20.4%) of whom had died of MCC at last follow-up. Human genes altered at high frequency included LRP1B (n = 10, 18.5%), FAT1 (n = 9, 16.7%), KMT2D (n = 9, 16.7%), and RB1 (n = 7, 13.0%). In 36 of 44 (81.8%) MCPyV-positive tumors, we identified viral integration into the human genome with a median of two events per tumor. In six tumors, MCPyV integrated into Catalogue of Somatic Mutations in Cancer tier 1 or tier 2 cancer-related human genes. IMPLICATIONS:A combined genomics score incorporating tumor mutational burden and copy-number variation was strongly prognostic of MCC-specific survival controlling for lymph node metastases and tumor MCPyV status; thus, our study adds critical understanding to prognostic markers and tumorigenic mechanisms in MCC.

Survival analyses for prognostic genetic signatures in MCC cohort. A-B. Kaplan-Meier curves for MCC-specific survival by t-TMB category in N+ patients (A) and VP-MCC patients (B). Kaplan-Meier curves for MCC-specific survival by CNV score category in N+ patients (C) and VP-MCC patients (D).

Scatter plot illustrating the correlation between the number of MCPV alterations per tumor and the corresponding number of MCPV reads and Variant Allele Frequency (VAF) plots for all single nucleotide variants and insertions/deletions identified in the cohort.

Summary of all MCPyV integration events in VP-MCC tumors.

Comparison of t-TMB and CNV scores by clinicopathologic variables in overall cohort. Data shown as median (range) or n (%) for continuous and categorical variables, respectively. Wilcoxon Rank-Sum and Kruskal-Wallis tests used for comparison of categorical and continuous variables, respectively. Additionally, we saw no correlation between primary tumor Breslow depth (mm) and t-TMB (Pearson’s r = -0.131, [95% CI: - 0.412 – 0.173], p = 0.397) or CNV score (Pearson’s r = -0.102, [95% CI: - 0.387 – 0.201], p = 0.511). a Data for primary tumor LVI and Breslow depth available for 45 of 54 (83.3%) patients.

Relative read depth across the MCPyV genome in each VP-MCC tumor. Left column shows MCPyV genome position (RefSeq NC_010277).

Read density plots for each of the tumors featured in Figure 1D.

Summary of definitive treatment modalities for MCC patients in our cohort, stratified by stage. Data presented as n (%). a Including sentinel lymph node biopsy ± completion lymphadenectomy of regional lymphatic basin.

Primary tumor histopathologic parameters for patients with MCC treated with surgery. Data presented as n (%) or median (range).

Representative MCPyV integration events in MiOTO_4055 and MiOTO_4003 that fell within human oncogenes. Red arrow: MCPyV integration; Black segment: contigs assembled at integration events; Segments with black arrowhead: zoomed in contigs aligned to the human genome; Segments with red arrowhead: zoomed in contigs aligned to the MCPyV genome. Direction of segments indicate the strand of contigs aligned to. Note figure constructed using MCPyViewer.

The NCCN Guidelines for Cutaneous Melanoma (termed Melanoma: Cutaneous) provide multidisciplinary recommendations for diagnostic workup, staging, and treatment of patients. These NCCN Guidelines Insights focus on the update to neoadjuvant systemic therapy options and summarize the new clinical data evaluated by the NCCN panel for the recommended therapies in Version 2.2024 of the NCCN Guidelines for Cutaneous Melanoma.

The NCCN Guidelines for Cutaneous Melanoma (termed Melanoma: Cutaneous) provide multidisciplinary recommendations for diagnostic workup, staging, and treatment of patients. These NCCN Guidelines Insights focus on the update to neoadjuvant systemic therapy options and summarize the new clinical data evaluated by the NCCN panel for the recommended therapies in Version 2.2024 of the NCCN Guidelines for Cutaneous Melanoma.

Background: Mohs micrographic surgery (MMS) is a promising treatment modality for melanoma in situ (MIS). However, variations in surgical technique limit the generalizability of existing data and may impede future study of MMS in clinical trials. Methods: A modified Delphi method was selected to establish consensus on optimal MMS techniques for treating MIS in future clinical trials. The Delphi method was selected due to the limited current data, the wide range of techniques used in the field, and the intention to establish a standardized technique for future clinical trials. A literature review and interviews with experienced MMS surgeons were performed to identify dimensions of the MMS technique for MIS that (1) likely impacted costs or outcomes of the procedure, and (2) showed significant variability between surgeons. A total of 8 dimensions of technical variation were selected. The Delphi process consisted of 2 rounds of voting and commentary, during which 44 expert Mohs surgeons across the United States rated their agreement with specific recommendations using a Likert scale. Results: Five of eight recommendations achieved consensus in Round 1. All 3 of the remaining recommendations achieved consensus in Round 2. Techniques achieving consensus in Round 1 included the use of a starting peripheral margin of ≤5 mm, application of immunohistochemistry, frozen tissue processing, and resecting to the depth of subcutaneous fat. Consensus on the use of Wood’s lamp, dermatoscope, and negative tissue controls was established in Round 2. Conclusions: This study generated 8 consensus recommendations intended to offer guidance for Mohs surgeons treating MIS. The adoption of these recommendations will promote standardization to facilitate comparisons of aggregate data in multicenter clinical trials.

The NCCN Guidelines for Cutaneous Melanoma (termed Melanoma: Cutaneous) provide multidisciplinary recommendations for diagnostic workup, staging, and treatment of patients. These NCCN Guidelines Insights focus on the update to neoadjuvant systemic therapy options and summarize the new clinical data evaluated by the NCCN panel for the recommended therapies in Version 2.2024 of the NCCN Guidelines for Cutaneous Melanoma.

The NCCN Guidelines for Cutaneous Melanoma (termed Melanoma: Cutaneous) provide multidisciplinary recommendations for diagnostic workup, staging, and treatment of patients. These NCCN Guidelines Insights focus on the update to neoadjuvant systemic therapy options and summarize the new clinical data evaluated by the NCCN panel for the recommended therapies in Version 2.2024 of the NCCN Guidelines for Cutaneous Melanoma.

Supplementary Figure S1. Transgenic constructs and validation of transgene expression in vivo. Supplementary Figure S2. Paranuclear dot-like expression of K8 and K5 in mouse MCC-like tumors. Supplementary Table S1. Correlation between transgene expression level, based on immunostaining, and phenotype severity. Supplementary Table S2.Primary antibodies and dilutions.

Supplementary Figures S1-S4

To the Editor: Sentinel lymph node biopsy (SLNB) is the current gold standard for staging patients with melanoma without evidence of regional nodal metastasis.1Morton D.L. Thompson J.F. Cochran A.J. et al.Sentinel-node biopsy or nodal observation in melanoma.N Engl J Med. 2006; 355: 1307-1317Crossref PubMed Scopus (1536) Google Scholar,2Swetter S.M. Tsao H. Bichakjian C.K. et al.Guidelines of care for the management of primary cutaneous melanoma.J Am Acad Dermatol. 2019; 80: 208-250Abstract Full Text Full Text PDF PubMed Scopus (325) Google Scholar Traditionally, patients found to have nodal disease with SLNB underwent immediate completion lymph node dissection (CLND), allowing for identification and removal of melanoma in nonsentinel nodes. However, recent studies have shown that close clinical follow-up with ultrasound imaging of the affected nodal basin can replace CLND for most patients.1Morton D.L. Thompson J.F. Cochran A.J. et al.Sentinel-node biopsy or nodal observation in melanoma.N Engl J Med. 2006; 355: 1307-1317Crossref PubMed Scopus (1536) Google Scholar, 2Swetter S.M. Tsao H. Bichakjian C.K. et al.Guidelines of care for the management of primary cutaneous melanoma.J Am Acad Dermatol. 2019; 80: 208-250Abstract Full Text Full Text PDF PubMed Scopus (325) Google Scholar, 3Faries M.B. Thompson J.F. Cochran A.J. et al.Completion dissection or observation for sentinel-node metastasis in melanoma.N Engl J Med. 2017; 376: 2211-2222Crossref PubMed Scopus (927) Google Scholar This protocol is now recommended in the National Comprehensive Cancer Network Melanoma Guidelines.2Swetter S.M. Tsao H. Bichakjian C.K. et al.Guidelines of care for the management of primary cutaneous melanoma.J Am Acad Dermatol. 2019; 80: 208-250Abstract Full Text Full Text PDF PubMed Scopus (325) Google Scholar Our study investigated patient compliance with ultrasound imaging follow-up and reviewed the frequency of use of other cross-sectional imaging methods for surveillance. Recurrences and mode of detection for each recurrence were noted. Patients treated for melanoma at our institution who had a positive SLNB but did not undergo CLND were identified. All patients received the recommendation to follow-up at our institution with ultrasound imaging every 4 months for 2 years, followed by ultrasound imaging every 6 months for the following 3 years. Compliance was defined as completion of ultrasound assessments within 150 days (4 months plus 30 days) for the first 2 years and within 210 days (6 months plus 30 days) thereafter. Because of concerns about variability in ultrasound imaging technique across institutions, patients were considered partially compliant if they received ultrasound imaging at an another institution or at prolonged intervals. Patients were considered noncompliant if they received no ultrasound assessments. The percentage of patients receiving computed tomography, positron emission tomography, or magnetic resonance during the surveillance period was also determined. Of 155 patients, 92 (59.4%) were considered fully compliant with follow-up, 58 (37.4%) were considered partially compliant, and 5 (3.2%) were noncompliant. There were 130 patients (83.9%) who had additional imaging (positron emission tomography, computed tomography, or magnetic resonance imaging) during surveillance. We documented 21 recurrences within the follow-up period (Tables I and II). Seven (33.3%) recurrences were first discovered on physical examination, 3 (14.3%) with ultrasound, and 11 (52.4%) by computed tomography or positron emission tomography.Table ICharacteristics of recurrences in patients fully compliant with Multicenter Selective Lymphadenectomy Trial IIPatientTime to recurrence, moType of recurrenceHow recurrence was detectedIndication for imagingRecurrence treatmentLiving?15LocalPhysical examNot applicableSurgeryYes25NodalPhysical examNot applicableSurgery, immunotherapyYes39Local, distantPhysical exam, PETPET staging after local recurrenceImmunotherapyNo43NodalUltrasoundSurveillanceImmunotherapyYes524NodalCTSurveillanceImmunotherapyYes614DistantPETSurveillanceUnknownYes719DistantCTSurveillanceClinical trialYes88NodalCTSurveillanceClinical trialNo99NodalUltrasoundSurveillanceSurgeryYes104DistantPhysical examNot applicableImmunotherapyYes1113DistantCTSurveillanceImmunotherapyYes1214NodalUltrasoundSurveillanceSurgeryYesCT, Computed tomography; PET, positron emission tomography. Open table in a new tab Table IICharacteristics of recurrences in patients partially compliant with the Multicenter Selective Lymphadenectomy Trial IIPatientTime to recurrence, moType of recurrenceHow recurrence was detectedIndication for imagingRecurrence treatmentLiving?115DistantPhysical examNot applicableSurgery, immunotherapyYes27DistantCTSymptomNoneNo313Nodal, distantCTSurveillanceSurgeryYes417In-transitPhysical examNot applicableUnknownYes512NodalCTSymptomUnknownYes618DistantCTSymptomImmunotherapy, radiotherapyYes714DistantCTSurveillanceImmunotherapyYes812DistantCTSurveillanceImmunotherapyYes96Local + in-transitPhysical examNot applicableSurgeryYesCT, Computed tomography. Open table in a new tab CT, Computed tomography; PET, positron emission tomography. CT, Computed tomography. Our results demonstrate that 40.6% of patients were not having ultrasound assessments as recommended. Furthermore, most of the recurrences, even in compliant patients, were identified by physical examination or cross-sectional imaging, not ultrasound. Limitations to our study include the small sample size and uncertainty regarding reasons for poor compliance. No conclusions can be made with respect to disease-related outcomes between the fully compliant and partially compliant groups. Nonetheless, our study highlights the difficulty in maintaining patient compliance with intense imaging recommendations. Close collaboration between patients and providers to ensure compliance is necessary to improve adherence to these regimens. Our data also suggest that patients at high risk for recurrence may benefit from multidisciplinary surveillance involving whole-body imaging, ultrasound, and physical examination at regular intervals. None disclosed.