{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,30]],"date-time":"2025-12-30T08:52:33Z","timestamp":1767084753424,"version":"build-2065373602"},"reference-count":46,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,2,18]],"date-time":"2022-02-18T00:00:00Z","timestamp":1645142400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Malignant melanoma (MM) is the most aggressive form of skin cancer, and around 30% of them may develop from pre-existing dysplastic nevi (DN). Diagnosis of DN is a relevant clinical challenge, as these are intermediate lesions between benign and malignant tumors, and, up to date, few studies have focused on their diagnosis. In this study, the accuracy of Raman spectroscopy (RS) is assessed, together with multivariate analysis (MA), to classify 44 biopsies of MM, DN and compound nevus (CN) tumors. For this, we implement a novel methodology to non-invasively quantify and localize the eumelanin pigment, considered as a tumoral biomarker, by means of RS imaging coupled with the Multivariate Curve Resolution-Alternative Least Squares (MCR-ALS) algorithm. This represents a step forward with respect to the currently established technique for melanin analysis, High-Performance Liquid Chromatography (HPLC), which is invasive and cannot provide information about the spatial distribution of molecules. For the first time, we show that the 5, 6-dihydroxyindole (DHI) to 5,6-dihydroxyindole-2-carboxylic acid (DHICA) ratio is higher in DN than in MM and CN lesions. These differences in chemical composition are used by the Partial Least Squares-Discriminant Analysis (PLS-DA) algorithm to identify DN lesions in an efficient, non-invasive, fast, objective and cost-effective method, with sensitivity and specificity of 100% and 94.1%, respectively.<\/jats:p>","DOI":"10.3390\/cancers14041056","type":"journal-article","created":{"date-parts":[[2022,2,21]],"date-time":"2022-02-21T08:14:46Z","timestamp":1645431286000},"page":"1056","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Novel Non-Invasive Quantification and Imaging of Eumelanin and DHICA Subunit in Skin Lesions by Raman Spectroscopy and MCR Algorithm: Improving Dysplastic Nevi Diagnosis"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8983-3612","authenticated-orcid":false,"given":"Jos\u00e9 Javier","family":"Ruiz","sequence":"first","affiliation":[{"name":"ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860 Barcelona, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4031-4605","authenticated-orcid":false,"given":"Monica","family":"Marro","sequence":"additional","affiliation":[{"name":"ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860 Barcelona, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6523-8592","authenticated-orcid":false,"given":"Ismael","family":"Galv\u00e1n","sequence":"additional","affiliation":[{"name":"Department of Evolutionary Ecology, National Museum of Natural Sciences, CSIC, 28006 Madrid, Spain"}]},{"given":"Jos\u00e9","family":"Bernabeu-Wittel","sequence":"additional","affiliation":[{"name":"Department of Dermatology, University Hospital Virgen del Rocio, 41013 Sevilla, Spain"}]},{"given":"Juli\u00e1n","family":"Conejo-Mir","sequence":"additional","affiliation":[{"name":"Department of Dermatology, University Hospital Virgen del Rocio, 41013 Sevilla, Spain"}]},{"given":"Teresa","family":"Zulueta-Dorado","sequence":"additional","affiliation":[{"name":"Department of Dermatology, University Hospital Virgen del Rocio, 41013 Sevilla, Spain"}]},{"given":"Ana Bel\u00e9n","family":"Guisado-Gil","sequence":"additional","affiliation":[{"name":"Department of Dermatology, University Hospital Virgen del Rocio, 41013 Sevilla, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3129-1213","authenticated-orcid":false,"given":"Pablo","family":"Loza-\u00c1lvarez","sequence":"additional","affiliation":[{"name":"ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels, 08860 Barcelona, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1111\/srt.12350","article-title":"Non-invasive tools for the diagnosis of cutaneous melanoma","volume":"23","author":"Fink","year":"2017","journal-title":"Skin. Res. Technol."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"18447","DOI":"10.1038\/srep18447","article-title":"Reverse Engineering Applied to Red Human Hair Pheomelanin Reveals Redox-Buffering as a Pro-Oxidant Mechanism","volume":"5","author":"Kim","year":"2015","journal-title":"Sci. Rep."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1.e1","DOI":"10.1016\/j.jaad.2012.02.047","article-title":"The dysplastic nevus: From historical perspective to management in the modern era: Part I. Historical, histologic, and clinical aspects","volume":"67","author":"Duffy","year":"2012","journal-title":"J. Am. Acad. Dermatol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1111\/j.1365-2559.2009.03450.x","article-title":"Dysplastic naevi: An update","volume":"56","author":"Elder","year":"2010","journal-title":"Histopathology"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Zhang, G., and Li, G. (2012). Novel multiple markers to distinguish melanoma from dysplastic nevi. PLoS ONE, 7.","DOI":"10.1371\/journal.pone.0045037"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Burns, T., Breathnach, S., Cox, N., and Griffiths, C. (2010). Lentigos, Melanocytic Naevi and Melanoma. Rook\u2019s Textbook of Dermatology, Wiley-Blackwell. [8th ed.].","DOI":"10.1002\/9781444317633"},{"key":"ref_7","unstructured":"Fletcher, C.D.M. (2007). Tumors of the skin. Diagnostic Histopathology of Tumors, Churchill Livingstone-Elsevier. [3th ed.]."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"764","DOI":"10.1097\/01.MP.0000082394.91761.E5","article-title":"Grading of atypia in nevi: Correlation with melanoma risk","volume":"16","author":"McNutt","year":"2003","journal-title":"Mod. Pathol."},{"key":"ref_9","unstructured":"Berwick, M., Buller, D.B., Cust, A., Gallagher, R., Lee, T.K., Meyskens, F., Pandey, S., Thomas, N.E., Veierod, M.B., and Ward, S. (2016). Melanoma, Springer International Publishing."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1111\/1346-8138.14737","article-title":"Histogenesis of cutaneous malignant melanoma: The vast majority do not develop from melanocytic nevus but arise de novo as melanoma in situ","volume":"46","author":"Saida","year":"2019","journal-title":"J. Dermatol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1071","DOI":"10.1016\/j.jaad.2014.08.025","article-title":"The utility of re-excising mildly and moderately dysplastic nevi: A retrospective analysis","volume":"71","author":"Strazzula","year":"2014","journal-title":"J. Am. Acad. Dermatol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"212","DOI":"10.1001\/jamadermatol.2014.2694","article-title":"Addressing the knowledge gap in clinical recommendations for management and complete excision of clinically atypical nevi\/dysplastic nevi: Pigmented Lesion Subcommittee consensus statement","volume":"151","author":"Kim","year":"2015","journal-title":"JAMA Dermatol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"024013","DOI":"10.1117\/1.2899155","article-title":"Raman microspectroscopy for skin cancer detection in vitro","volume":"13","author":"Lieber","year":"2008","journal-title":"J. Biomed. Opt."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1388","DOI":"10.1001\/archderm.141.11.1388","article-title":"The performance of SolarScan: An automated dermoscopy image analysis instrument for the diagnosis of primary melanoma","volume":"141","author":"Menzies","year":"2005","journal-title":"Arch. Dermatol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"461","DOI":"10.1002\/lsm.20653","article-title":"In vivo nonmelanoma skin cancer diagnosis using Raman microspectroscopy","volume":"40","author":"Lieber","year":"2008","journal-title":"Lasers Surg. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1186\/s11671-019-3039-2","article-title":"Raman Techniques: Fundamentals and Frontiers","volume":"14","author":"Jones","year":"2019","journal-title":"Nanoscale Res. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"5594","DOI":"10.1021\/acs.analchem.7b04527","article-title":"Unravelling the Metabolic Progression of Breast Cancer Cells to Bone Metastasis by Coupling Raman Spectroscopy and a Novel Use of Mcr-Als Algorithm","volume":"90","author":"Marro","year":"2018","journal-title":"Anal. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"R370","DOI":"10.1088\/0031-9155\/61\/23\/R370","article-title":"A review of Raman spectroscopy advances with an emphasis on clinical translation challenges in oncology","volume":"61","author":"Jermyn","year":"2016","journal-title":"Phys. Med. Biol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2491","DOI":"10.1158\/0008-5472.CAN-11-4061","article-title":"Real-time Raman spectroscopy for in vivo skin cancer diagnosis","volume":"72","author":"Lui","year":"2012","journal-title":"Cancer Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"14554","DOI":"10.3390\/ijms160714554","article-title":"Advances in the in Vivo Raman Spectroscopy of Malignant Skin Tumors Using Portable Instrumentation","volume":"16","author":"Kourkoumelis","year":"2015","journal-title":"Int. J. Mol. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"e201900016","DOI":"10.1002\/tbio.201900016","article-title":"Incorporating patient demographics into Raman spectroscopy algorithm improves in vivo skin cancer diagnostic specificity","volume":"1","author":"Zhao","year":"2019","journal-title":"Transl. Biophotonics"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"770","DOI":"10.1039\/c3pp25344a","article-title":"Diagnosis of malignant melanoma and basal cell carcinoma by in vivo NIR-FT Raman spectroscopy is independent of skin pigmentation","volume":"12","author":"Philipsen","year":"2012","journal-title":"Photochem. Photobiol. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"117003","DOI":"10.1117\/1.JBO.19.11.117003","article-title":"Clinical study of noninvasive in vivo melanoma and nonmelanoma skin cancers using multimodal spectral diagnosis","volume":"19","author":"Lim","year":"2014","journal-title":"J. Biomed. Opt."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1339","DOI":"10.1038\/s41416-018-0257-9","article-title":"Improving clinical diagnosis of early-stage cutaneous melanoma based on Raman spectroscopy","volume":"119","author":"Santos","year":"2018","journal-title":"Br. J. Cancer"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2835","DOI":"10.1364\/BOE.8.002835","article-title":"Raman active components of skin cancer","volume":"8","author":"Feng","year":"2017","journal-title":"Biomed. Opt. Express"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"057002","DOI":"10.1117\/1.JBO.23.5.057002","article-title":"Raman biophysical markers in skin cancer diagnosis","volume":"23","author":"Feng","year":"2018","journal-title":"J. Biomed. Opt."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1111\/j.1755-148X.2011.00864.x","article-title":"Usefulness of alkaline hydrogen peroxide oxidation to analyze eumelanin and pheomelanin in various tissue samples: Application to chemical analysis of human hair melanins","volume":"24","author":"Ito","year":"2011","journal-title":"Pigment Cell Melanoma Res."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"809","DOI":"10.1111\/pcmr.12805","article-title":"A novel LC-MS\/MS method to quantify eumelanin and pheomelanin and their relation to UVR sensitivity-A study on human skin biopsies","volume":"32","author":"Lerche","year":"2019","journal-title":"Pigment Cell Melanoma Res."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Marro, M., Rodr\u00edguez-Rivero, A.M., Araujo-Andrade, C., Fern\u00e1ndez-Figueras, M.T., P\u00e9rez-Roca, L., Castell\u00e0, E., Navin\u00e9s, J., Mariscal, A., Juli\u00e1n, J.F., and Turon, P. (2021). Unravelling the Encapsulation of DNA and Other Biomolecules in HAp Microcalcifications of Human Breast Cancer Tissues by Raman Imaging. Cancers, 13.","DOI":"10.3390\/cancers13112658"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.aca.2020.10.051","article-title":"Multivariate Curve Resolution: 50 years addressing the mixture analysis problem-A review","volume":"1145","author":"Tauler","year":"2021","journal-title":"Anal. Chim. Acta"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1100","DOI":"10.1111\/srt.13069","article-title":"Combining Raman imaging and MCR-ALS analysis for monitoring retinol permeation in human skin","volume":"27","author":"Essendoubi","year":"2021","journal-title":"Skin. Res. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"759","DOI":"10.1016\/j.jaad.2007.01.014","article-title":"Sensitivity, specificity, and diagnostic accuracy of three dermoscopic algorithmic methods in the diagnosis of doubtful melanocytic lesions: The importance of light brown structureless areas in differentiating atypical melanocytic nevi from thin melanomas","volume":"56","author":"Annessi","year":"2007","journal-title":"J. Am. Acad. Dermatol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"3526","DOI":"10.1039\/C8AN00599K","article-title":"Partial least squares-discriminant analysis (PLS-DA) for classification of high-dimensional (HD) data: A review of contemporary practice strategies and knowledge gaps","volume":"143","author":"Lee","year":"2018","journal-title":"Analyst"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1007\/s00345-007-0184-5","article-title":"Technical aspects of lasers in urology","volume":"25","author":"Teichmann","year":"2007","journal-title":"World J. Urol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"765","DOI":"10.1023\/B:INET.0000008930.87741.b9","article-title":"Background Subtraction in Experimental Data Arrays Illustrated by the Example of Raman Spectra and Fluorescent Gel Electrophoresis Patterns","volume":"46","author":"Mikhailyuk","year":"2003","journal-title":"Instrum. Exp. Tech."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"614","DOI":"10.1080\/05704928.2014.882348","article-title":"Development of a Dewaxing Protocol for Tissue-Engineered Models of the Oral Mucosa Used for Raman Spectroscopic Analysis","volume":"49","author":"Mian","year":"2014","journal-title":"Appl. Spectrosc. Rev."},{"key":"ref_37","first-page":"14","article-title":"Selecting an Excitation Wavelength for Raman Spectroscopy","volume":"31","author":"Tuschel","year":"2016","journal-title":"Spectroscopy"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"C723","DOI":"10.1152\/ajpcell.00462.2010","article-title":"A practical guide to evaluating colocalization in biological microscopy","volume":"300","author":"Dunn","year":"2011","journal-title":"Am. J. Physiol. Cell Physiol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1016\/j.saa.2013.03.027","article-title":"Vibrational characterization of pheomelanin and trichochrome F by Raman spectroscopy","volume":"110","author":"Jorge","year":"2013","journal-title":"Spectrochim. Acta. Part A Mol. Biomol. Spectrosc."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"1198","DOI":"10.1117\/1.1805553","article-title":"Raman spectroscopy of in vivo cutaneous melanin","volume":"9","author":"Huang","year":"2004","journal-title":"J. Biomed. Opt."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1111\/pcmr.12707","article-title":"Raman spectroscopy quantification of eumelanin subunits in natural unaltered pigments","volume":"31","author":"Marro","year":"2018","journal-title":"Pigment. Cell Melanoma Res."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"S4","DOI":"10.1038\/modpathol.3800515","article-title":"Precursors to melanoma and their mimics: Nevi of special sites","volume":"19","author":"Elder","year":"2006","journal-title":"Mod. Pathol."},{"key":"ref_43","unstructured":"Van Nieuwpoort, A.F. (2011). Biochemical and Molecular Studies of Atypical Nevi. [Ph.D. Thesis, Leiden University Medical Center (LUMC), Leiden University]. Available online: https:\/\/hdl.handle.net\/1887\/16632."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"352","DOI":"10.1086\/680362","article-title":"Melanin chemistry and the ecology of stress","volume":"88","author":"Solano","year":"2015","journal-title":"Physiol. Biochem. Zool."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1016\/j.chemolab.2004.12.011","article-title":"Performance of some variable selection methods when multicollinearity is present","volume":"78","author":"Chong","year":"2005","journal-title":"Chemom. Intell. Lab. Syst."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"53","DOI":"10.1097\/00008390-199802000-00009","article-title":"Phaeomelanin versus eumelanin as a chemical indicator of ultraviolet sensitivity in fair-skinned subjects at high risk for melanoma: A pilot study","volume":"8","author":"Vincensi","year":"1998","journal-title":"Melanoma Res."}],"container-title":["Cancers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6694\/14\/4\/1056\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T22:22:54Z","timestamp":1760134974000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6694\/14\/4\/1056"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,2,18]]},"references-count":46,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2022,2]]}},"alternative-id":["cancers14041056"],"URL":"https:\/\/doi.org\/10.3390\/cancers14041056","relation":{},"ISSN":["2072-6694"],"issn-type":[{"type":"electronic","value":"2072-6694"}],"subject":[],"published":{"date-parts":[[2022,2,18]]}}}