Circulating tumour cells lacking cytokeratin in breast cancer: the importance of being mesenchymal.

Circulating tumour cells (CTCs) are independent predictor of prognosis in metastatic breast cancer. Nevertheless, in one third of patients, circulating tumour cells are undetected by conventional methods. Aim of the study was to assess the prognostic value of circulating tumour cells expressing mesenchymal markers in metastatic breast cancer patients. We isolated CTC from blood of 55 metastatic breast cancer patients. CTC were characterized for cytokeratins and markers of epithelial mesenchymal transition. The gain of mesenchymal markers in CTC was correlated to prognosis of patients in a follow-up of 24 months. The presence of mesenchymal markers on CTC more accurately predicted worse prognosis than the expression of cytokeratins alone. Because of the frequent loss of epithelial antigens by CTC, assays targeting epithelial antigens may miss the most invasive cell population. Thus, there is an urgent need to improve detection methods to identify CTC which undergone epithelial mesenchymal transition program.

Epithelial-mesenchymal transition and stemness features in circulating tumor cells from breast cancer patients.

Currently used methods to detect and enumerate circulating tumor cells (CTCs) rely on the expression of the epithelial cell adhesion molecule (EpCAM) and cytokeratins. This selection may exclude cells that have undergone intrinsic modifications of their phenotype, as epithelial-mesenchymal transition (EMT). Aim of the study was to investigate the expression of EMT and stemness markers in CTCs from breast cancer patients in all stages of disease. 92 female breast cancer patients were enrolled. CTCs were isolated by CELLection Dynabeads coated with the monoclonal antibody toward EpCam. Samples found positive for CTCs presence (CD45-/CK+) were evaluated for the expression of ER alpha, HER2, ALDH1, vimentin, and fibronectin. Samples negative for CTCs presence (CD45-/CK-) were also evaluated for the expression of vimentin and fibronectin, used as markers of EMT. CTCs were found in 66% of patients. The distribution of CTCs presence according to stage and grade of disease was found statistically significant. The expression of ALDH1 on CTCs was found to correlate to stage of disease and to the expression of vimentin and fibronectin. In 34% of patients, we detected cells with negative CK/CD45 expression but positive expression of vimentin and fibronectin. There is an urgent need for optimizing CTCs detection methods through the inclusion of EMT markers. The detection of cells in mesenchymal transition, retaining EMT and stemness features, may contribute to discover additional therapeutic targets useful to eradicate micrometastatic disease in breast cancer.

Molecular markers in circulating tumour cells from metastatic colorectal cancer patients.

The prognosis of metastatic cancer patients is still largely affected by treatment failure, mainly due to drug resistance. The hypothesis that chemotherapy might miss circulating tumour cells (CTCs) and particularly a subpopulation of more aggressive, stem-like CTCs, characterized by multidrug resistance, has been recently raised. We investigated the prognostic value of drug resistance and stemness markers in CTCs from metastatic colorectal cancer patients treated with oxaliplatin (L-OHP) and 5-fluoruracil (5-FU) based regimens. Forty patients with metastatic colorectal cancer were enrolled. CTCs were isolated from peripheral blood and analysed for the expression of aldheyde dehydrogenase 1 (ALDH1), CD44, CD133 (used as markers of stemness), multidrug resistance related protein 5 (MRP5 used as marker of resistance to 5-FU and L-OHP) and survivin (used as a marker of apoptosis resistance). CTCs were found in 27/40 (67%) patients. No correlation was found between the expression of either CD44 and CD133 in CTCs and the outcome of patients, while a statistically significant shorter progression-free survival was found in patients with CTCs positive for the expression of ALDH1, survivin and MRP5. These results support the idea that isolating survivin and MRP5+ CTCs may help in the selection of metastatic colorectal cancer patients resistant to standard 5-FU and L-OHP based chemotherapy, for which alternative regimens may be appropriate.

Prognostic significance of survivin-expressing circulating tumour cells in T1G3 bladder cancer.

OBJECTIVE: To evaluate the prognostic significance of survivin in tumour tissues and that of survivin-expressing circulating tumour cells (CTCs) in T1G3 bladder tumours, as the prognosis of T1G3 bladder cancer is highly variable and unpredictable from clinical and pathological prognostic factors. PATIENTS AND METHODS: The study included 54 patients with T1G3 non-muscle-invasive bladder cancer. Additional inclusion criteria were: tumour size <3 cm, absence of carcinoma in situ and multifocality. The planned follow-up was 24 months. Survivin was evaluated by reverse transcription-polymerase chain reaction in tumour tissues. CTCs were isolated from blood by CELLection Dynabeads (Invitrogen, Carlsbad, CA, USA) coated with the monoclonal antibody towards the human epithelial cell adhesion molecule. Cells were lysed and Dynabeads Oligo(dT) was used to capture poly A + mRNA. cDNA was synthesized and analysed for the expression of CD45, CK8 and survivin. The primary endpoint was disease-free survival (DFS); the favourable group at 24 months was defined as that with no clinical evidence of disease; the unfavourable group was that with evidence of recurrent disease or progressive disease. Tumour survivin expression and presence of CTC were correlated with DFS. Multivariate analysis was used to investigate whether the presence of CTC was an independent indicator of DFS. RESULTS: Survivin was found in half of the tumours; patients with survivin-negative tumours had a longer DFS than those with survivin-positive tumours (chi-square, P = 0.029). CTCs were found in 24/54 patients (44%); 92% of CTC expressed survivin. The difference in DFS between CTC-ve and CTC+ve patients was statistically significant (chi-square, P < 0.001). The presence of CTC was an independent prognostic factor for DFS (P < 0.001). CONCLUSION: The presence of CTC is an independent prognostic factor in patients with T1G3 bladder cancer.

Circulating tumor cells count and characterization in a male breast cancer patient.

A 64-y-old man presented to Medical Oncology Department a metastatic invasive ductal breast carcinoma, positive for estrogen (ER) and progesterone receptors (PR) and Her2/neu negative. The patient was treated with different lines of therapy, with rapid radiological progression of disease. After four courses of a third-line chemotherapy, a radiological stable disease was maintained. The patient was followed by serial blood drawings for the characterization and count of circulating tumor cells (CTC). This is the first report concerning the predictive and prognostic value of CTC in a male breast cancer patient.

Circulating tumor cells and "suspicious objects" evaluated through CellSearch® in metastatic renal cell carcinoma.

BACKGROUND: Recent evidence supports the hypothesis that the CellSearch assay, used in the enumeration of circulating tumor cells (CTCs), may underestimate the number of CTCs, especially in tumors, such as renal cell carcinoma, frequently lacking cytokeratin expression. According to the CellSearch guidelines, all objects with no clear cytokeratin staining are defined as "suspicious objects", and are not counted as CTCs. The aim of this study was to investigate the presence of CTCs and "suspicious objects" in 25 patients affected by metastatic renal cell carcinoma (mRCC). PATIENTS AND METHODS: Twenty-five patients were enrolled in the study, all with a diagnosis of metastatic clear cell RCC. The CellSearch™ system was used to count the CTC in 7.5 mL of whole blood. A further 10 ml blood obtained from each patient was used to isolate CTCs through CELLection™ Dynabeads®. The expression of cytokeratin (CK) 8, 18, 19 and CD44 were evaluated by RT-PCR. RESULTS: Standard CTCs and suspicious objects were found in 16% and 60% of the patients, respectively. CK-8/18/19 transcripts were found in 15% and CD44 in 68% of the 19 patients with evidence of classical CTC or "suspicious objects" as assessed by Cellsearch. CONCLUSION: The low number of CTCs detected through CellSearch in renal cell carcinoma may be due to the presence of a CTC population with atypical characteristics and a peculiar gene expression profile, characterized by lack of cytokeratin expression and gain of CD44.