Fig. 4

Characterization of CTC heterogeneity: expression pattern and cell morphology. a Collected CTCs are heterogeneous and display different combinations of PSA and CK within each patient sample. Cells classified as CTCs in healthy patient samples also exhibit all combinations of PSA and CK markers. b CK+ CTCs (mean 15.9 ± 6.9 µm) were significantly smaller in diameter than CK− CTCs (mean 26.2 ± 6.5 µm), which suggests potential morphological changes in cells undergoing EMT. c CTCs displayed all combinations of PSA and CK expression with varying size and nuclear fraction. The majority of CTCs were either PSA+/CK− (n = 66) or PSA−/CK+ (n = 60). d CTCs isolated from patients had similar sizes and morphologies as the few similarly classified cells found from healthy donors. CTCs displayed a wide range of sizes (mean 21.1 ± 8.4 µm), and the average diameter and nuclear fraction of CTCs were greater than those of 22RV1 PC and WBC control cells