The Novel Association of Circulating Tumor Cells and Circulating Megakaryocytes with Prostate Cancer Prognosis

Purpose: To develop an approach for the investigation of different subtypes of circulating tumor cells (CTC) and other cells to evaluate their potential prognostic value of prostate cancer.

Experimental Design: Malignancy of CTCs undergoing epithelial-to-mesenchymal transition (EMT) was confirmed by repeated FISH. Subgroups of CTCs in 81 patients with prostate cancer (43 castration resistant and 38 untreated localized) were correlated to disease aggressiveness parameters. AUC analysis was applied to compare the performance for metastasis prediction between serum PSA level alone and a combined risk score using both PSA and EMTing CTC count. Circulating megakaryocytes and cancer patient survival association was performed using Cox model.

Results: The majority of vimentin (VIM)⁺/CD45^– cells were malignant, with genomic alterations in several genomic regions. The number of cytokeratin (CK)^–/VIM⁺/CD45^– CTCs correlated with disease burden, tumor aggressiveness, and poorer survival. Meanwhile, CK⁺/VIM⁺/CD45^– CTCs were associated with metastases better than other subtypes of CTCs in these limited samples. Combination of PSA level and the number of CK⁺/VIM⁺/CD45^– CTCs enhanced the prediction of cancer metastases [AUC, 0.921; 95% confidence interval (CI), 0.858–0.985]. The number of circulating megakaryocytes was potentially associated with good patient survival in advanced prostate cancer (HR, 0.849; 95% CI, 0.628–1.146, per cell increase), and the difference between the number of mesenchymal CTCs and megakaryocytes strongly correlated to poor survival (HR, 10.17; 95% CI, 2.164–47.789, if score ≥2.0).

Conclusions: This CTC analysis approach and the potential association of megakaryocytes with cancer prognosis may greatly enhance our ability to investigate the cancer metastasis process and to predict/monitor cancer progression. Clin Cancer Res; 23(17); 5112–22. ©2017 AACR.

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