• Cancer stem cells
• chemosensitivity
• metastatic cancer

A recent hypothesis is that cancer is driven by a small subpopulation of cells called “cancer stem cells” (CSCs) with an unlimited proliferative potential. These cells are thought to be responsible for the development of the tumor representing the only cell population able to sustain tumor growth and progression. In the present study we investigated whether CSCs could be isolated in patients with metastatic lung cancer (LC), breast cancer (BC) and colorectal cancer (CRC) and whether in vitro CSCs sensitivity assay could identify an effective treatment. The study was conducted in NSCLC patients with metastatic disease progressing after standard therapies. CSCs were isolated from effusions or fresh cancer tissue from primary tumor or metastasis. CSCs were cultivated in vitro and tested against different chemotherapy or targeted agents. The drug or the drugs combination leading to the highest CSC mortality rate was further administered to the patient. A total of 23 patients were included onto the study. Main characteristics were: median age 66 years (range 42-85), male sex in 14 cases (60%), with LC in 18 cases (78%), CRC in 3 cases (13%), other gastrointestinal adenocarcinoma in 2 cases (9%). CSCs were obtained from liver metastases in 6 cases (25%), pleural lung nodule excision in 2 cases (8%), lymphnode excision in 3 cases (12,5%) and by pleural or peritoneal effusion in 13 cases (54%). CSCs were successfully isolated in 15 patients (65%). Main reasons for CSCs isolation failure included inadequate material (6 cases), contamination (1 case) or delivery problems. CSC sensitivity assay was performed in 7 cases (29%), with a median of 15 drugs or combinations tested (range 5-28). The median time between cancer tissue collection and sensitivity assay result was 51 days (range 37-95). Our preliminary data indicate that CSCs isolation and in vitro sensitivity assay are feasible in patients with metastatic NSCLC.