Comparison of Tissue Molecular Biomarker Testing Turnaround Times and Concordance Between Standard of Care and the Biocartis Idylla Platform in Patients With Colorectal Cancer.

OBJECTIVES: Management of colorectal cancer warrants mutational analysis of KRAS/NRAS when considering anti-epidermal growth factor receptor therapy and BRAF testing for prognostic stratification. In this multicenter study, we compared a fully integrated, cartridge-based system to standard-of-care assays used by participating laboratories. METHODS: Twenty laboratories enrolled 874 colorectal cancer cases between November 2017 and December 2018. Testing was performed on the Idylla automated system (Biocartis) using the KRAS and NRAS-BRAF cartridges (research use only) and results compared with in-house standard-of-care testing methods. RESULTS: There were sufficient data on 780 cases to measure turnaround time compared with standard assays. In-house polymerase chain reaction (PCR) had an average testing turnaround time of 5.6 days, send-out PCR of 22.5 days, in-house Sanger sequencing of 14.7 days, send-out Sanger of 17.8 days, in-house next-generation sequencing (NGS) of 12.5 days, and send-out NGS of 20.0 days. Standard testing had an average turnaround time of 11 days. Idylla average time to results was 4.9 days with a range of 0.4 to 13.5 days. CONCLUSIONS: The described cartridge-based system offers rapid and reliable testing of clinically actionable mutation in colorectal cancer specimens directly from formalin-fixed, paraffin-embedded tissue sections. Its simplicity and ease of use compared with other molecular techniques make it suitable for routine clinical laboratory testing.

Detection of WA B cells in hepatitis C virus infection: a potential prognostic marker for cryoglobulinemic vasculitis and B cell malignancies.

OBJECTIVE: An uncommon manifestation of hepatitis C virus (HCV) infection is systemic vasculitis associated with type II cryoglobulinemia (cryoglobulinemic vasculitis), a proliferative B cell disorder that transforms into B cell malignancy in 5-10% of patients. The monoclonal rheumatoid factors (mRF) that bear the WA cross-idiotype (Xid) are responsible for most cases of cryoglobulinemic vasculitis in patients with HCV infection. The purpose of this study was to determine whether WA B cells can be detected in asymptomatic patients with HCV infection, using sequence analysis of B cell clonal expansions (BCEs) to identify the WA Xid. METHODS: Asymptomatic patients with HCV infection and those without HCV infection as well as respective control patients with cryoglobulinemic vasculitis, whose serum was either negative or positive for WA mRF, were studied. BCEs were isolated in the patients' blood, and WA BCEs were identified by sequencing analysis. RESULTS: BCEs were detected in all control patients with cryoglobulinemic vasculitis, but only control patients with HCV infection had WA BCEs. None of the 33 asymptomatic patients without HCV infection had a BCE. WA BCEs were detected in 4 (7.4%) of 55 asymptomatic patients with HCV infection, in none of 14 patients with HCV infection and type III cryoglobulinemia, and in 5 (13.5%) of 37 patients with HCV infection and serum RF positivity. One patient with a WA BCE had splenic lymphoma markers and villous lymphocytes, and the villous lymphocytes were found to be WA B cells. CONCLUSION: By identification of the WA Xid, WA B cells can be detected in asymptomatic HCV-infected patients. WA B cells in asymptomatic patients with HCV infection may be a marker for the development of cryoglobulinemic vasculitis and associated B cell malignancies. The results of this study provide a basis for the development of the first practical clinical application of cross-idiotype analysis.