Performance of a typical good quality FFPE-DNA diagnostic sample with the three methods applied for KRAS mutation assessment.
A and B: Corresponding tissue section with areas marked for macrodissection containing ∼70% tumor cells. Some necrotic areas can not be avoided but in this analogy these do not interfere with DNA extraction. The estimated number of sectioned neoplastic cells in B is ∼4000. For good quality samples, KRAS mutation assessment is reliable with any method, as shown in C (sequencing, c. 34 G>A corresponding to the G12S change), in D (TMGB-KRAS, G12S mutation positive) and in E (DxS-KRAS, G12S mutation positive). DNA control Ct values <29 (arrow) were yielded with both real time PCR methods (red curves in D and E).