title: Optical diagnosis of actinic cheilitis by infrared spectroscopy.
abstract: Actinic cheilitis (AC) is considered a potentially malignant disorder of the lip. Biomolecular markers study is important to understand malignant transformation into squamous cell carcinoma. Fourier transform infra red (FT-IR) spectroscopy was used to analyze AC in this study.
  
  
  OBJECTIVE
  The aim of the study was to evaluate if FT-IR spectral regions of nucleic acids and collagen can help in early diagnosis of malignant transformation.
  
  
  METHODS
  Tissues biopsies of 14 patients diagnosed with AC and 14 normal tissues were obtained. FT-IR spectra were measured at five different points resulting in 70 spectra of each. Analysis of Principal components analysis (PCA) and linear discrimination analysis (LDA) model were also used. In order to verify the statistical difference in the spectra, Mann-Whitney U test was performed in each variable (wavenumber) with p-value <0.05.
  
  
  RESULTS
  After the Mann-Whitney U test the vibrational modes of CO (Collagen 1), PO2 (Nucleic Acids) and CO asymmetric (Triglycerides/Lipids) were observed as a possible spectral biomarker. These bands were chosen because they represent the vibrational modes related to collagen and DNA, which are supposed to be changed in AC samples. Based on the PCA-LDA results, the predictive model corresponding to the area under the curve was 0.91 for the fingerprint region and 0.83 for the high wavenumber region, showing the greater accuracy of the test.
  
  
  CONCLUSIONS
  FT-IR changes in collagen and nucleic acids could be used as molecular biomarkers for malignant transformation.
authors: Laboratory of Biomedical Vibrational Spectroscopy, Universidade do Vale do Paraíba, São José dos Campos, São Paulo, Brazil. Electronic address: luisfelipecarvalho@hotmail.com.
authors: Luis Felipe
authors: LF
authors: das Chagas E Silva de Carvalho
authors: Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos campos, São Paulo, Brazil.
authors: Thiago Martini
authors: TM
authors: Pereira
authors: Laboratory of Biomedical Vibrational Spectroscopy, Universidade do Vale do Paraíba, São José dos Campos, São Paulo, Brazil.
authors: Taciana Depra
authors: TD
authors: Magrini
authors: Department of Biosciences and Oral Diagnosis, Institute of Science and Technology, Univ Estadual Paulista (UNESP), São José dos Campos, São Paulo, Brazil.
authors: Ana Sueli Rodrigues
authors: AS
authors: Cavalcante
authors: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, São Paulo, Brazil.
authors: Herculano
authors: H
authors: da Silva Martinho
authors: Department of Biosciences and Oral Diagnosis, Institute of Science and Technology, Univ Estadual Paulista (UNESP), São José dos Campos, São Paulo, Brazil.
authors: Janete Dias
authors: JD
authors: Almeida
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D002613:Cheilitis / Q000175:diagnosis* / Q000378:metabolism*; D003094:Collagen / Q000032:analysis*; D003627:Data Interpretation, Statistical; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009696:Nucleic Acids / Q000032:analysis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013055:Spectrophotometry, Infrared / Q000379:methods*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D009696:Nucleic Acids; D003094:Collagen
keywords: Actinic cheilitis; FT-IR spectroscopy; Optical biopsy; Oral cancer