Cancers 2022, 14, 3053. https://doi.org/10.3390/cancers14133053 www.mdpi.com/journal/cancers Article Clinical Utility of Liquid Biopsy to Detect BRAF and NRAS Mutations in Stage III/IV Melanoma Patients by Using Real-Time PCR Emilio Francesco Giunta 1 , Vincenzo De Falco 1 , Pietro Paolo Vitiello 2,3 , Luigi Pio Guerrera 1,4 , Gabriella Suarato 1 , Rossella Napolitano 1 , Alessandra Perrone 1 , Giuseppe Argenziano 5 , Renato Franco 6 , Michele Caraglia 7 , Erika Martinelli 1 , Davide Ciardiello 1,4 , Fortunato Ciardiello 1 , Stefania Napolitano 1, * and Teresa Troiani 1, * 1 Medical Oncology Unit, Department of Precision Medicine, Università degli Studi della Campania “Luigi Vanvitelli”, 80131 Naples, Italy; emiliofrancesco.giunta@unicampania.it (E.F.G.); vincenzodefalc@gmail.com (V.D.F.); luigipioguerrera@hotmail.it (L.P.G.); gabriella.suarato@gmail.com (G.S.); rossella.napolitano@unicampania.it (R.N.); alessandra.perrone@unicampania.it (A.P.); erika.martinelli@unicampania.it (E.M.); davideciardiello@yahoo.it (D.C.); fortunato.ciardiello@unicampania.it (F.C.) 2 Candiolo Cancer Institute, FPO-IRCCS, 10060 Candiolo, TO, Italy; pietropaolo.vitiello@gmail.com 3 Department of Oncology, University of Torino, 10060 Candiolo, TO, Italy 4 Medical Oncology Unit, Ospedale Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy 5 Dermatology Unit, Department of Mental and Physical Health and Preventive Medicine, Università degli Studi della Campania “Luigi Vanvitelli”, 80131 Naples, Italy; giuseppe.argenziano@unicampania.it 6 Pathology Unit, Department of Mental and Physical Health and Preventive Medicine, Università degli Studi della Campania “Luigi Vanvitelli”, 80138 Naples, Italy; renato.franco@unicampania.i t 7 Department of Precision Medicine, AOU Policlinico Vanvitelli, Università degli Studi della Campania “Luigi Vanvitelli”, 80138 Naples, Italy; michele.caraglia@unicampania.it * Correspondence: stefania.napolitano@unicampania.it (S.N.); teresa.troiani@unicampania.it (T.T.) Simple Summary: Liquid biopsy is an increasingly used tool for melanoma diagnosis and molecu- lar characterization, but also for monitoring of response to anticancer drugs. The aim of our work is to assess the clinical utility of a real-time quantitative PCR (qPCR)-based platform with a very short turnaround time and identify the best setting for clinical investigation. We investigated the concordance of this technique with tissue analysis in stage III–IV melanoma patients; moreover, we correlated results to clinicopathologic characteristics and outcomes. We found a higher tissue– plasma concordance in melanoma patients with high burden of disease (sum of diameters ≥30 mm, ≥2 metastatic sites, elevated LDH levels), constituting a clinical subgroup worthy of future prospec- tive evaluation; however, the low sensitivity of this technique seems to be not sufficient for predict- ing relapses in radically resected patients. Abstract: Background: Liquid biopsy is a potentially useful tool for melanoma patients, also for detecting BRAS/NRAS mutations, even if the tissue analysis remains the current standard. Methods: In this work, we tested ctDNA on plasma samples from 56 BRAF-V600/NRAS mutant stage III/IV melanoma patients using a real-time quantitative PCR (qPCR)-based platform. The study popula- tion was divided into two cohorts: the first including 26 patients who had undergone radical resec- tion (resected cohort) and the second including 30 patients who had unresected measurable disease (advanced cohort). Moreover, for 10 patients in the advanced cohort, ctDNA assessment was re- peated at specified timepoints after baseline testing. Data were analyzed and correlated to the clini- copathologic characteristics and outcomes. Results: In the baseline cohort, a higher tissue–plasma concordance was seen in patients with high burden of disease (sum of diameters ≥30 mm, ≥2 meta- static sites, elevated LDH levels); furthermore, monitoring of these patients through ctDNA analysis was informative for therapeutic responses. On the other hand, the low sensitivity of this technique did not allow for clinically valuable prediction of relapses in radically resected stage III/IV patients. Conclusions: Overall, our data suggest that qPCR-based ctDNA analysis could be informative in a Citation: Giunta, E.F.; De Falco, V.; Vitiello, P.P.; Guerrera, L.P.; Suarato, G.; Napolitano, R.; Perrone, A.; Argenziano, G.; Franco, R.; Caraglia, M.; et al. Clinical Utility of Liquid Biopsy to Detect BRAF and NRAS Mutations in Stage III/IV Melanoma Patients by Using Real-Time PCR. Cancers 2022, 14, 3053. https://doi.org/10.3390/ cancers14133053 Received: 24 April 2022 Accepted: 20 June 2022 Published: 21 June 2022 Publisher’s Note: MDPI stays neu- tral with regard to jurisdictional claims in published maps and institu- tional affiliations. Copyright: © 2022 by the authors. Li- censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con- ditions of the Creative Commons At- tribution (CC BY) license (https://cre- ativecommons.org/licenses/by/4.0/).