Table 4 Summary of single-cell sequencing studies of CTCs and DTCs
From: Single-cell sequencing and tumorigenesis: improved understanding of tumor evolution and metastasis
Cell type | Tumor type (number of cells, patients) | Data type | Results | Reference |
|---|---|---|---|---|
CTCs | ||||
| Â | Colorectal (37, 6) | Targeted sequencing | Most mutations in CTCs are present in sub-clonal populations of the primary tumor or metastases, but some mutations are exclusive to CTCs | [67] |
Lung (68, 11) | WES/WGS | CNVs in CTCs are dissimilar between cancer subtypes; patterns of SNVs and INDELs in CTCs change during treatment, but CNVs remain constant | [68] | |
Prostate (99, 1) | WGS | SNVs and structural variations in CTCs are also present in primary tumors or metastases | [69] | |
Prostate (25, 2) | WES | The majority of mutations in CTCs are also present in the primary tumor and metastases | [70] | |
Breast (14, 4) | Targeted sequencing | High levels of heterogeneity in CTCs within and between patients as well as before and after treatment | [71] | |
Breast (115, 18) | Targeted sequencing | In some patients heterogeneity of PIK3CA mutations is observed among CTCs and between CTCs and the primary tumor | [72] | |
Breast (11, 2) | Targeted sequencing | Some CTCs carry the same TP53 mutation(s) as the primary carcinoma, other CTCs carry different mutations | [73] | |
Breast (185, 12) | Targeted sequencing | CTCs show genetic heterogeneity of PIK3CA mutations over time and discordance between DTCs and metastases | [74] | |
Breast (22, 2) | RNA-seq | HER2Â +Â CTCs may arise in HER2- breast cancer patients and may contribute to progression and drug resistance | [75] | |
Prostate (77, 13) | RNA-seq | Heterogeneity in expression of androgen receptor mutations between CTCs within patients may influence treatment response | [77] | |
DTCs | ||||
| Â | Breast (24, 1) | Targeted sequencing | DTCs show genetic discordance of PIK3CA mutations versus CTCs and metastases; mutations are stable during cell culture | [74] |
Breast (2, 2) | WGS | In one patient, DTC was highly concordant with the non-complex primary tumor; DTC from complex primary tumor showed greater genetic divergence | [82] | |
Neuroblastoma (144, 10) | Targeted sequencing | Mutational status for the ALK gene is concordant between the primary tumor and DTCs for all patients | [84] | |
Breast (63, 6) | WGS | Some DTCs originate from clones in the primary carcinoma, other DTCs arise from LN metastases | [85] | |