Figure 2.

Yield and quality of DNA obtained from formalin‐fixed paraffin‐embedded (FFPE) samples prepared in routine practice. The yield and quality of DNA obtained from FFPE tissue samples of 233 patients with solid tumors analyzed in the first term of the TOP‐GEAR project were examined. DNA was extracted from five 10‐µm sections using the QIAamp DNA FFPE Tissue Kit (Qiagen). (a) The cross‐sectional tissue area was measured and multiplied by 50 µm to calculate the tissue volume. The surgical and biopsy specimens were assessed and compared (including samples not because they were from other institutions). The DNA yield per volume varied widely among the samples, with the biopsy specimens exhibiting a higher yield than the surgical specimens. (b) After DNA quality assessment using Q‐values (quantity of DNA measured using qPCR/quantity of double‐stranded DNA measured using the fluorescence method), the quality was compared between the surgical and biopsy specimens. The Q‐values varied widely among the samples, with the biopsy specimens exhibited better quality than the surgical specimens