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Comparison of protocols for removal of melanin from genomic DNA to optimize PCR amplification of DNA purified from highly pigmented lesions.
Vicente, Anna Luiza Silva Almeida; Bianchini, Raquel Alves; Laus, Ana Carolina; Macedo, Graziela; Reis, Rui Manuel; Vazquez, Vinicius de Lima.
Afiliação
  • Vicente ALSA; Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil.
  • Bianchini RA; Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil.
  • Laus AC; Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil.
  • Macedo G; Department of Pathology, Barretos Cancer Hospital, Barretos, São Paulo, Brazil.
  • Reis RM; Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil.
  • Vazquez VL; Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal.
Histol Histopathol ; 34(9): 1089-1096, 2019 Sep.
Article em En | MEDLINE | ID: mdl-30949991
Melanin is produced by melanocytes and protects against DNA damage by ultraviolet light. Unfortunately, the melanin protein present in melanoma tumor cells is often co-purified during DNA extraction, and this contamination may inhibit subsequent PCR methods, which directly impacts research applications and the molecular diagnostic tests needed for targeted therapeutics. There are presently no described purification protocols that efficiently remove melanin from genomic DNA. In this study, we compare six different methods for melanin removal from genomic DNA: Agarose Gel Electrophoresis, 1mg Chelex®-100, Chelex®-100 5%, centrifugation, OneStep™ PCR Inhibitor Removal Kit and centrifugation plus OneStep™ PCR Inhibitor Removal Kit. Each comparison was made using 16 formalin-fixed paraffin-embedded (FFPE) and 11 fresh cell line samples. All samples were initially tested using the multiplex PCR reaction for GAPDH gene that generates different sized amplified products: 100, 200, 300 and 400 base pairs, which could be inhibited by the addition of exogenous melanin. Six purification protocols were then applied, and all samples that amplified at least one GAPDH fragment were sequenced to analyze the presence of the BRAF V600E mutation. The efficiencies of amplification decreased for larger sized fragments in all methods. Our comparisons showed that centrifugation combined with the OneStep™ PCR Inhibitor Removal Kit was superior to all other methods for successful BRAF sequencing with 100% (100bp), 75% (200bp), 50% (300bp), and 31.3% (400bp) amplification efficiencies for the different amplicon sizes. In conclusion, this genomic DNA extraction method is highly efficient for successful PCR when tumor samples are contaminated with melanin.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: DNA de Neoplasias / Reação em Cadeia da Polimerase / Melaninas / Melanoma Tipo de estudo: Guideline Limite: Humans Idioma: En Revista: Histol Histopathol Assunto da revista: HISTOLOGIA / PATOLOGIA Ano de publicação: 2019 Tipo de documento: Article País de afiliação: Brasil País de publicação: Espanha

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: DNA de Neoplasias / Reação em Cadeia da Polimerase / Melaninas / Melanoma Tipo de estudo: Guideline Limite: Humans Idioma: En Revista: Histol Histopathol Assunto da revista: HISTOLOGIA / PATOLOGIA Ano de publicação: 2019 Tipo de documento: Article País de afiliação: Brasil País de publicação: Espanha