Mutations in the EGFR gene are biomarkers that guide the targeted therapy of Non-Small Cell Lung Cancer (NSCLC). When the mutation assay was performed on small Formalin-Fixed, Paraffin-Embedded (FFPE) biopsies in which only a limited number of tumor cells were obtained, determining Limit of detection of cell number (LODCN) was helpful for quality control. An NCL-H1975 cell block was used to determine the range of LODCN for EGFR mutations. The in-house LODCN was set based on the results of 10 samples with known EGFR mutations. The other 35 samples were assayed to validate the LODCN value. The consistency of 35 clinical validated samples was 100% in samples with more than 70 tumor cells. LODCN could be a useful quality control parameter for mutation assays on small FFPE samples with a very limited number of tumor cells.
Keywords: EGFR mutation test; FFPE; LOD of cell number; NSCLC; small specimens.
© 2020 by the Association of Clinical Scientists, Inc.