Table 2.
Mutations detected by four commercially available ctDNA detection platforms in cfDNA from 11 patients with mCRC isolated with the QIAsymphony and distributed equally over all platforms.
| Tissue KRAS resulta | Months between tissue biopsy and blood collection | total cfDNA analysed (ng)b | Reported mutant copies (mAF)c | ddPCR | Idylla | COBAS z480 | BEAMing |
|---|---|---|---|---|---|---|---|
| KRAS p.G12_G12insAG | Unknown | 23.7 | 9 (0.12%) | ntd | nt | nt | KRAS p.G12X |
| KRAS p.G12V | Unknown | 23.0 | 1167 (15.4%) | KRAS p.G12X/G13X | KRAS p.G12V | KRAS p.G12X | KRAS p.G12X |
| KRAS p.A146T | 9 | 17.3 | 106 (1.7%) | nt | KRAS p.A146T | KRAS p.146× | KRAS p.A146T |
| KRAS p.G12D | 0 | 94.4 | 39 (0.13%) | KRAS p.G12X/G13X | KRAS p.G12D | KRAS p.G12X | KRAS p.G12X |
| KRAS p.G13D | Unknown | 8.1 | nd | nde | KRAS p.G13D | nd | nd |
| KRAS p.G12V | Unknown | 167.0 | 4656 (8.5%) | KRAS p.G12X/G13X | KRAS p.G12V | KRAS p.G12X | KRAS p.G12X |
| KRAS p.G12C | 5 | 10.1 | nd | nd | nd | nd | nd |
| KRAS p.G12D | 9 | 13.7 | nd | nd | nd | nd | nd |
| KRAS p.G12D | 20 | 8.2 | nd | nd | KRAS p.G12D | nd | nd |
| KRAS p.G13D | 22 | 10.2 | nd | nd | nd | nd | nd |
| KRAS amplification | Unknown | 4.2 | nd | nt | nt | nt | nt |
| Overall sensitivity (%) | 38%f | 67% | 44% | 50% |
aThe KRAS mutation status was determined in tissue using the method of choice of the hospital of inclusion.
bTotal cfDNA input per method is based on Qubit measurement of cfDNA isolated by QIAsymphony using the Circulating DNA kit.
cReported mutant copies and mutant allele frequency (mAF) are based on BEAMing results.
dnt = not targeted.
end = not detected.
fdetected mutations divided by the total number of mutations detectable by that platform.