TP53, EGFR and PIK3CA gene variations observed as prominent biomarkers in breast and lung cancer by plasma cell-free DNA genomic testing

J Biotechnol. 2019 Jul 20;300:87-93. doi: 10.1016/j.jbiotec.2019.05.005. Epub 2019 May 14.


Use of plasma cell-free DNA genomic testing, also know as liquid biopsy, reveals information for early detection and monitoring of solid tumors. Our study reports the analysis of 113 lung and 18 breast cancer patients using commercially available platforms. Lung and breast cancer panel hotspot regions on the genes were investigated. There was a significant increase in isolation efficiency with very fresh blood samples of at least 15 millilitres which were processed in minutes. TP53 gene variations were detected in both types of tumors. Additionally, associations were found for EGFR variations in lung tumors and PIK3CA variations in breast tumors. Mutation assessment of these three genes are recommended as useful biomarkers for predictive studies, to follow up tumor growth and for personalized treatment. Mutations observed in this study warrant further investigation for follow up studies and may justify expression studies. However, in our subsequent studies, we intensify our tumor profiling strategy with other methods. However in terms of true personalized medicine,future plans would include repeating these studies with ctDNA size analysis and methylation analysis of the non-coding region in the individual tumors.

Keywords: Breast cancer; Cell-Free DNA; EGFR; Lung cancer; PIK3CA; TP53.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / genetics
  • Breast Neoplasms / blood
  • Breast Neoplasms / diagnosis*
  • Breast Neoplasms / genetics
  • Circulating Tumor DNA / blood*
  • Circulating Tumor DNA / genetics
  • Class I Phosphatidylinositol 3-Kinases / genetics*
  • Early Detection of Cancer
  • ErbB Receptors / genetics
  • Female
  • Genetic Variation
  • Humans
  • Liquid Biopsy
  • Lung Neoplasms / blood
  • Lung Neoplasms / diagnosis*
  • Lung Neoplasms / genetics
  • Male
  • Middle Aged
  • Tumor Suppressor Protein p53 / genetics*


  • Biomarkers, Tumor
  • Circulating Tumor DNA
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Class I Phosphatidylinositol 3-Kinases
  • PIK3CA protein, human
  • EGFR protein, human
  • ErbB Receptors