Scientists from the National University of Singapore (NUS) have developed a novel technique to efficiently culture clusters containing circulating tumour cells (CTCs) in 14 days. The study has shown that CTCs can predict the outcome of cancer treatment and assists clinicians on patients' chemotherapy regimen, as well as to monitor the status of cancer. This work was a collaborative research partnership between (MBI & CSI) NUS and the National University Cancer Institute, Singapore (NCIS).
Using 226 blood samples, the team achieved a success rate of >60% in culturing CTCs from patients with metastatic breast cancer. As according to the study, it is the highest known success record to-date. Professor Lim Chwee Teck from MBI and one of the lead authors explained, 'Being able to capture CTCs and grow them efficiently from a blood sample is a big step forward in liquid biopsy for tumour diagnosis and cancer treatment monitoring. This could potentially mean that biopsy for cancer diagnosis and prognosis could be done using a blood test, which is minimally invasive, instead of having to remove cells from the tumour itself (i.e. tumour biopsy).'
'Results of the blood tests could help doctors assess the best therapy options for a patient, and frequent blood tests can also be done during the course of an anti-cancer treatment to monitor a patient's progress during treatment.'
'CTCs are heterogeneous and it is formed when cancer cells metastasize and escape from the primary tumour. The cancer cells then enter the bloodstream, and a few cells then travel downstream and invade other parts of the body to establish secondary tumours. These runaway cells are called CTCs, and they can be found at early stages of cancer disease,' said Prof Lim.
'Tests can potentially be done on the cultured CTCs to guide the selection of drug therapy', added Adjunct Associate Professor Lee Soo Chin, Associate Director (Research) and Senior Consultant of NCIS, who is also a Senior Principal Investigator from CSI, and the clinical lead for the study.
'Cultured CTCs of individual patients can be tested for drug sensitivity to determine the re-sponsiveness of the CTCs to the drugs that are commonly used in the treatment of cancers. This could allow doctors to decide on the most suitable drug for the patient based on the drug sensitivity results. As the CTCs can be cultured in a short time period, the entire testing process can take as short as four weeks; two weeks for culturing the CTCs and two weeks for drug screening. Patients will not have to wait a long time for the test results.'
After two to three weeks of surgery, chemotherapy has to take place, which is why a quick diagnostic and efficient method is required to identify the presence of CTCs clusters. Due to the heterogeneity of CTCs, CTCs is considered to comprise many sub-populations and occur at extremely low frequencies in blood. According to Prof Lim, 'The chance of getting CTCs in a blood sample is akin to trying to find a hundred people in a world of seven billion people.'
Due to its rarity, CTCs needs to be expanded before each clinical analysis. NUS scientists have hence developed a novel methodology to efficiently culture clusters containing CTCs from patients' blood samples. An ideal environment was also created to ensure the growth of CTCs cells and not non-cancerous cells; using a combination of specially designed mi-crowells and oxygen deficient growth conditions. N.B: A hypoxia environment limits the growth of non-cancerous cells, but promotes CTCs growth.
Professor Lim is also looking forward to embark on the development of novel technologies that can contribute towards personalized or precision medicine. The team is looking forward to apply their novel technology on more prevalent diseases in Asia.
The study is published in Oncotarget (2015).