Table 4. Comparison of protein expression between CTCs, primary tumors, and metastases.
| Primary tumor | Metastasis | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ER (n=18)* | PR (n=16)* | HER2 (n=22)* | ER (n=19)* | PR (n=17)* | HER2 (n=23)* | ||||||||
| - | + | - | + | - | + | - | + | - | + | - | + | ||
| CTC protein expression | - | 4 | 4 | 5 | 4 | 17 | 4 | 5 | 3 | 7 | 3 | 18 | 4 |
| + | 2 | 8 | 2 | 5 | 1 | 0 | 3 | 8 | 3 | 4 | 1 | 0 | |
| Sensitivity | 66.7% | 55.6% | 0 | 72.7% | 57.1% | 0 | |||||||
| Specificity | 66.7% | 71.4% | 94.4% | 62.5% | 70.0% | 94.7% | |||||||
| Positive predictive value | 80.0% | 71.4% | 0 | 72.7% | 57.1% | 0 | |||||||
| Negative predictive value | 50.0% | 55.6% | 80.9% | 62.5% | 70.0% | 81.8% | |||||||
| Accuracy | 66.7% | 62.5% | 77.3% | 68.4% | 64.7% | 78.2% | |||||||
Abbreviations: CTC, circulating tumor cells; ER, estrogen receptor; PR, progesterone receptor. *Differences in the number of patients are because of the fact that although CTCs were detected in the blood, they were absent in some ISET® spots, as explained in the section of Immunocytochemistry in Materials and Methods.