Implementation of formalin-fixed, paraffin-embedded cell line pellets as high-quality process controls in quality assessment programs for KRAS mutation analysis.

In recent years, the mutational status of the KRAS oncogene has become incorporated into standard medical care as a predictive marker for therapeutic decisions related to patients with metastasized colorectal cancer. This is necessary, because these patients benefit from epidermal growth factor receptor (EGFR)-targeted therapy with increased progression-free survival only if the tumor does not carry a mutation in KRAS. Many different analytical platforms, both those commercially available and those developed in house, have been used within pathology laboratories to assess KRAS mutational status. For a testing laboratory to become accredited to perform such tests, it is essential that they perform reliability testing, but it has not previously been possible to perform this kind of testing on the complete workflow on a large scale without compromising reproducibility or the mimicry of the control sample. We assessed a novel synthetic control for formalin-fixed, paraffin-embedded (FFPE) tumor samples in a blind study conducted within nine laboratories across Europe. We show that FFPE material can, at least in part, mimic clinical samples and we demonstrate this control to be a valuable tool in the assessment of platforms used in testing for KRAS mutational status.

External quality assessment for KRAS testing is needed: setup of a European program and report of the first joined regional quality assessment rounds.

The use of epidermal growth factor receptor-targeting antibodies in metastatic colorectal cancer has been restricted to patients with wild-type KRAS tumors by the European Medicines Agency since 2008, based on data showing a lack of efficacy and potential harm in patients with mutant KRAS tumors. In an effort to ensure optimal, uniform, and reliable community-based KRAS testing throughout Europe, a KRAS external quality assessment (EQA) scheme was set up. The first large assessment round included 59 laboratories from eight different European countries. For each country, one regional scheme organizer prepared and distributed the samples for the participants of their own country. The samples included unstained sections of 10 invasive colorectal carcinomas with known KRAS mutation status. The samples were centrally validated by one of two reference laboratories. The laboratories were allowed to use their own preferred method for histological evaluation, DNA isolation, and mutation analysis. In this study, we analyze the setup of the KRAS scheme. We analyzed the advantages and disadvantages of the regional scheme organization by analyzing the outcome of genotyping results, analysis of tumor percentage, and written reports. We conclude that only 70% of laboratories correctly identified the KRAS mutational status in all samples. Both the false-positive and false-negative results observed negatively affect patient care. Reports of the KRAS test results often lacked essential information. We aim to further expand this program to more laboratories to provide a robust estimate of the quality of KRAS testing in Europe, and provide the basis for remedial measures and harmonization.