Methods for molecular monitoring of ctDNA for non-Hodgkin lymphoma
| . | ctDNA of IgH . | ctDNA of VDJ sequence . | Tumor genotypic ctDNA . |
|---|---|---|---|
| Technique | Allele-specific PCR | PCR + NGS | NGS |
| Primary tumor required | Yes | No* | No† |
| Sensitivity‡ | 1 in 105 | 1 in 106 | Unknown |
| Processing time | Weeks | 1-2 wk | 1-2 wk |
| Track clonal evolution | No | Limited | Possible |
| Track resistance | No | Limited | Possible |
| Potential | Tumor-specific Quantifiable | Tumor-specific Quantifiable Universal primers Rapid turnaround time | Broad genomic coverage Track clonal evolution Track resistance mechanisms |
| Limitations | Not universal Specific primers required Limited foci assessed | Limited genotypic information | Low allele frequency Molecular heterogeneity of tumor |
| . | ctDNA of IgH . | ctDNA of VDJ sequence . | Tumor genotypic ctDNA . |
|---|---|---|---|
| Technique | Allele-specific PCR | PCR + NGS | NGS |
| Primary tumor required | Yes | No* | No† |
| Sensitivity‡ | 1 in 105 | 1 in 106 | Unknown |
| Processing time | Weeks | 1-2 wk | 1-2 wk |
| Track clonal evolution | No | Limited | Possible |
| Track resistance | No | Limited | Possible |
| Potential | Tumor-specific Quantifiable | Tumor-specific Quantifiable Universal primers Rapid turnaround time | Broad genomic coverage Track clonal evolution Track resistance mechanisms |
| Limitations | Not universal Specific primers required Limited foci assessed | Limited genotypic information | Low allele frequency Molecular heterogeneity of tumor |
IgH, immunoglobulin heavy chain; NGS, next-generation sequencing; PCR, polymerase chain reaction; VDJ, variable-diversity-joining region of the immunoglobulin receptor.
Tumor clonotype can be determined without baseline tissue, but the yield is lower.
Mutational panels common to lymphoma subtypes would obviate the need for baseline tumor.
Sample size required to detect 1 cellular equivalent.