Targeting the epidermal growth factor receptor (EGFR) is a new therapeutic option for patients with metastatic colorectal or lung carcinoma. However, the therapy efficiency highly depends on the KRAS mutation status in the given tumour. Therefore a reliable and secure KRAS mutation testing is crucial. Here we investigated 100 colorectal carcinoma samples with known KRAS mutation status (62 mutated cases and 38 wild type cases) in a comparative manner with three different KRAS mutation testing techniques (Pyrosequencing, Dideoxysequencing and INFINITI) in order to test their reliability and sensitivity. For the large majority of samples (96/100, 96%), the KRAS mutation status obtained by all three methods was the same. Only two cases with clear discrepancies were observed. One case was reported as wild type by the INFINITI method while the two other methods detected a G13C mutation. In the second case the mutation could be detected by the Pyrosequencing and INFINITI method (15% and 15%), while no signal for mutation could be observed with the Dideoxysequencing method. Additional two unclear results were due to a detection of a G12V with the INFINITI method, which was below cut-off when repeated and which was not detectable by the other two methods and very weak signals in a G12V mutated case with the Dideoxy- and Pyroseqencing method compared to the INFINITI method, respectively. In summary all three methods are reliable and robust methods in detecting KRAS mutations. INFINITI, however seems to be slightly more sensitive compared to Dideoxy- and Pyrosequencing.
Institute of Pathology, University Hospital Basel, Schoenbeinstrasse, Basel, Switzerland
Funding: For the duration of the experiments, BÜHLMANN Laboratory AG supplied the INFINITI Analyser and the 3 INFINITI KRAS-BRAF kit sets (48 tests per kit), including all reagents. An all-inclusive participation of CHF 4'500, including the experimental procedures, data evaluation, writing of reports, and applying to the Ethics Committee, was also attributed to BÜHLMANN Laboratories AG. Additional funding was provided by the Institute of Pathology from the University Hospital Basel.
The authors declare no conflict of interest.
Reprints: Michel P. Bihl, PhD, Institute of Pathology, University Hospital Basel, Schoenbeinstrasse 40, 4031 Basel, Switzerland (e-mail: firstname.lastname@example.org).