Performance evaluation comparison of 3 commercially available PCR-based KRAS mutation testing platforms.

The identification of KRAS mutations in patients with certain types of cancer, including colonic adenocarcinoma and non-small cell lung carcinoma, has become increasingly important as these patients are contraindicated from receiving epidermal growth factor receptor-targeted therapies. Several polymerase chain reaction (PCR)-based tests are commercially available for KRAS mutation testing including Applied Biosystems KRAS Mutation Analysis on the ABI3130xl, Qiagen therascreen KRAS RGQ PCR on the Rotor-Gene Q MDx, and Qiagen KRAS Pyro on the PyroMark Q24; however, these tests have not been compared side by side. The purpose of this study was to evaluate the performance characteristics and workflow for 3 PCR-based methods of detecting KRAS mutation status. We evaluated the performance characteristics and workflow for 3 commercially available KRAS mutation detection platforms. All of the 188 samples run were successful, with 29% being positive for the KRAS mutation. Of the positive tests, Applied Biosystems detected 84% of the positive cases, whereas Qiagen therascreen RGQ and Qiagen KRAS Pyro detected 100% of the positive cases. In cases of discrepancy between Applied Biosystems and therascreen RGQ, Pyro agreed with therascreen RGQ 95% of the time. Qiagen therascreen RGQ and Pyro were comparable in terms of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy, with all values being 100%. All 3 techniques accurately identified the appropriate mutation in the known control specimens. In summary, all 3 tests are relatively comparable for detecting the KRAS mutation, with Applied Biosystems having a slightly lower sensitivity, negative predictive value, and accuracy than therascreen RGQ and Pyro.

KRAS mutation is present in a small subset of primary urinary bladder adenocarcinomas.

AIMS: To determine whether KRAS mutations occur in primary bladder adenocarcinoma. METHODS AND RESULTS: Twenty-six cases of primary urinary bladder adenocarcinoma were analysed. DNA was extracted from formalin-fixed, paraffin-embedded tissue and amplified with shifted termination assay technology, which recognizes wild-type or mutant target sequences and selectively extends detection primers with labelled nucleotides. A mutation in KRAS was found in three (11.5%) of 26 primary bladder adenocarcinomas. Two of these three cases exhibited a G13D mutation, whereas the remaining case contained a mutation in G12V. None of the ten cases of urothelial carcinoma with glandular differentiation displayed KRAS mutation. Colonic adenocarcinoma contained a KRAS mutation in 18 (33%) of 55 cases. There was no distinct difference with regard to grade, stage or outcome according to the limited clinicopathological data available. However, the two youngest patients, aged 32 and 39 years, in our study group, with a mean population age of 61 years, were found to have mutations in KRAS. CONCLUSIONS: KRAS mutations are present in a small subset of primary urinary bladder adenocarcinomas. Future clinical trials for treatment of bladder adenocarcinoma, employing targeted therapies similar to those used for treatment of colon cancer, may also benefit from the predictive implications of KRAS mutational testing.