Analytical validity of DecisionDx-SCC, a gene expression profile test to identify risk of metastasis in cutaneous squamous cell carcinoma (SCC) patients

Association of a 40-Gene Expression Profile With Risk of Metastatic Disease Progression of Cutaneous Squamous Cell Carcinoma and Specification of Benefit of Adjuvant Radiation Therapy

PURPOSE

Adjuvant radiation therapy (ART) for cutaneous squamous cell carcinoma is recommended based on a number of wide-ranging clinicopathologic features, which encompass a broad array of patients. The 40-gene expression profile (GEP) test classifies cutaneous squamous cell carcinoma tumors into low (class 1), higher (class 2A), or highest (class 2B) risk of nodal and/or distant metastasis. This study's hypotheses are as follows: (1) local recurrence is associated with metastatic disease progression and (2) 40-GEP, by identifying high risk for metastasis, could predict a metastasis-specific benefit from ART.

METHODS AND MATERIALS

Samples were obtained from 920 patients (ART-untreated: 496 class 1, 335 class 2A, and 33 class 2B; ART-treated: 11 class 1, 35 class 2A, and 10 class 2B) who were matched on clinical risk factors and stratified by ART status to create 49 matched patient strata. To control for the variety of characteristics and treatment selection bias, randomly sampled pairs of matched ART and non-ART patients comprising 10,000 resampled cohorts were each analyzed for 5-year metastasis-free survival and predicted time to metastatic event.

RESULTS

Of 96 patients experiencing local recurrence, 56.3% experienced metastasis; of those experiencing both, 88.9% experienced local recurrence before (75.9%) or concurrently (13.0%) with metastasis. After matching for clinicopathologic risk, median 5-year disease progression rates for resampled cohorts demonstrated approximately 50% improvement for class 2B ART-treated compared with ART-untreated cohorts. ART-treated class 2B cohorts had a 5-fold delay in predicted time to metastatic event and deceleration of disease progression compared with ART-untreated cohorts (Kolmogorov-Smirnov test, P < .01); this was not observed for patients with class 1 or 2A cSCC (P > .05 for each). No risk factor or staging system combined with ART status identified groups that would benefit from ART as well as 40-GEP.

CONCLUSIONS

Forty-GEP identifies patients at the highest risk of nodal/distant metastasis who may derive the greatest benefit from ART, as well as patients who may have clinical indications for ART but are at low risk of metastasis. Compared with current guidelines, 40-GEP could provide greater specificity concerning the benefit of ART in individual patients.

Rapidly Growing Giant Squamous Cell Carcinoma of the Head: A Case Report

Giant squamous cell carcinoma (GSCC) of the skin arising on the head presents a distinctive clinical challenge due to its rarity, aggressive behavior, and potential for disfigurement. A male in his 70s with a history of tobacco cigarette use presented to the emergency department with a painful, bleeding mass on the right parietal scalp. On admission, a brain CT revealed a fungating mass with no cortical breakthrough or osseous erosion, measuring 7.9 x 5.7 x 2.5 cm. An ultrasound-guided tissue biopsy was performed and revealed poorly differentiated squamous cell carcinoma. The patient was discharged home with instructions from oncology to continue with outpatient treatment. At this time, the prognosis is good if treatment is received.

Integrating the 40-Gene Expression Profile (40-GEP) Test Improves Metastatic Risk-Stratification Within Clinically Relevant Subgroups of High-Risk Cutaneous Squamous Cell Carcinoma (cSCC) Patients

INTRODUCTION

The validated 40-gene expression profile (40-GEP) test independently stratifies risk of regional or distant metastasis for cutaneous squamous cell carcinoma (cSCC) tumors with high-risk clinicopathologic features. This study evaluated the stratification of risk by the 40-GEP test in a large cohort of tumors with one or more high-risk factors and in clinically relevant subgroups, including tumors within National Comprehensive Cancer Network (NCCN) high- and very-high-risk groups, lower-stage BWH T1 and T2a tumors, and patients > 65 years old.

METHODS

This multicenter (n = 58) performance study of the 40-GEP included 897 patients. Kaplan-Meier analyses were performed to assess risk stratification profiles for 40-GEP Class 1 (low), Class 2A (higher) and Class 2B (highest) risk groups, while nested Cox regression models were used to compare risk prediction of clinicopathologic risk classification systems versus risk classification systems in combination with 40-GEP.

RESULTS

Patients classified as 40-GEP Class 1, Class 2A, or Class 2B had significantly different metastatic risk profiles (p < 0.0001). Integrating 40-GEP results into models with individual clinicopathologic risk factors or risk classification systems (Brigham and Women's Hospital, American Joint Committee on Cancer Staging Manual, 8th Edition) and NCCN demonstrated significant improvement in accuracy for prediction of metastatic events (ANOVA for model deviance, p < 0.0001 for all models).

CONCLUSION

The 40-GEP test demonstrates accurate, independent, clinically actionable stratification of metastatic risk and improves predictive accuracy when integrated into risk classification systems. The improved accuracy of risk assessment when including tumor biology via the 40-GEP test ensures more risk-aligned, personalized patient management decisions.

Analytical validation of the PROphet test for treatment decision-making guidance in metastatic non-small cell lung cancer

The blood proteome, consisting of thousands of proteins engaged in various biological processes, acts as a valuable source of potential biomarkers for various medical applications. PROphet is a plasma proteomics-based test that serves as a decision-support tool for non-small cell lung cancer (NSCLC) patients, combining proteomic profiling using SomaScan technology and subsequent computational algorithm. PROphet was implemented as a laboratory developed test (LDT). Under the Clinical Laboratory Improvement Amendments (CLIA) and Commission on Office Laboratory Accreditation (COLA) regulations, prior to releasing patient test results, a clinical laboratory located in the United States employing an LDT must examine its performance characteristics with regard to analytical validity. This study describes the experimental and computational analytical validity of the PROphet test, as required by CLIA/COLA regulations. Experimental precision analysis displayed a median coefficient of variation (CV) of 3.9 % and 4.7 % for intra-plate and inter-plate examination, respectively, and the median accuracy rate between sites was 88 %. Computational precision exhibited a high accuracy rate, with 93 % of samples displaying complete concordance in results. A cross-platform comparison between SomaScan and other proteomics platforms yielded a median Spearman's rank correlation coefficient of 0.51, affirming the consistency and reliability of the SomaScan platform as used under the PROphet test. Our study presents a robust framework for evaluating the analytical validity of a platform that combines an experimental assay with subsequent computational algorithms. When applied to the PROphet test, strong analytical performance of the test was demonstrated.

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.