Liquid biopsy: can we detect cancer early?

Wednesday 28 February 2024.

Liquid biopsy: can we detect cancer early?

Wednesday 28 February 2024.
Online debate.

  • Time is of the essence in cancer: the earlier a tumour is detected and diagnosed, the better the chances of successful treatment and a good prognosis. But the problem is that the disease often goes undetected during its early stages, so that it has already advanced by the time the first signs are detected in the form of symptoms or other indicators.

    This is why new techniques enabling earlier diagnosis are vital. An emerging method that has been put forward as an early detection tool, even in apparently healthy individuals, is that of a liquid biopsy, which detects biological traces of the tumour in blood or other fluids. The test is performed on a sample of blood, urine or other body fluid in order to look for cancer cells or small pieces of DNA, RNA or other molecules that are released by tumour cells into body fluids.

    This new technique represents a major advance over a traditional tissue biopsy, which requires samples of tumour tissue to be extracted by puncture, incision or surgery so that they can be examined in the laboratory. The main drawback of this traditional tissue biopsy method is that it is invasive and uncomfortable, in addition to its inability to provide continuous monitoring of disease progression.

    In contrast, liquid biopsies avoid inconveniences for the patient and save time, because the analysis results are ready within a few days. Additionally, given that the procedure for collecting fluid samples from the patient involves a safe, quick and virtually painless process, it can be repeated as many times as necessary over time in order to monitor the evolution of a disease that is dynamic and constantly changing. A better understanding of tumour biology and genetics facilitates decisions that are to be made regarding treatment so that it can be adapted to the specific features of each cancer.

    Oncologists can use liquid biopsies to acquire highly valuable information about the disease with a minimally invasive technique: ranging from its mere presence to whether a treatment is working or whether it is generating resistance and needs to be altered. Liquid biopsies can be applied in many cases. They are already being used to monitor mutations in a metastatic setting and are also being introduced in a surgical setting in order to refine prognosis after certain operations. The third and most difficult application is to use them to detect cancer in asymptomatic people. Recent studies have provided new evidence for the potential of liquid biopsies in this course of action: early detection in asymptomatic people. Nonetheless, the technique still needs to be honed if it is to become a screening tool for the general public in the long term.

    The researchers in charge of three projects supported by the CaixaImpulse Innovation Programme of the ”la Caixa” Foundation are participating in this discussion. They are working to further the development of this new technique and facilitate its transfer to routine clinical practice. What do they involve? What progress has been made?

    One of the obstacles that has hindered implementing this new technique is the difficulty of detecting potential biomarkers present in the blood. Cancer cells release exosomes into the bloodstream that travel to other parts of the body. These are small vesicles that form inside cells and contain several cellular proteins, as well as portions of DNA and RNA. The team led by Dr Inmaculada Ibáñez has developed a test that facilitates exosome content analysis. This enables the detection of biomarkers and helps to stratify lung disease patients at risk of developing lung cancer and to make recommendations for the therapeutic suitability of those receiving chemotherapy treatment.

    The team led by Dr Lorena Diéguez is following along the same lines to develop a system called RUBYchip that is based on the liquid biopsy technique. This will enable oncologists to make a personalised diagnosis for each patient, choose the most appropriate therapy, monitor the disease’s progress in an efficient and minimally invasive manner, predict possible resistance to treatment, and select a new therapeutic regimen with a higher probability of success.

    The team co-led by Dr Cristina Saura is focusing its efforts on breast cancer occurring during pregnancy and post-partum. This is the most common type of cancer in women under the age of 45, and it is usually diagnosed in advanced stages compared to other breast cancers, thereby worsening its prognosis. The team’s previous studies have shown that mother’s milk from breast cancer patients contains DNA derived from tumour cells. Based on this discovery, the team will conduct a clinical trial involving more than 5,000 women using a test developed in the team’s lab. The aim is to determine the suitability of liquid biopsies in breast milk as a diagnostic test for detecting pregnancy-associated breast cancer at early stages in order to include this new diagnostic system in routine clinical practice.


    • Olga Vera, junior main researcher of the Experimental Therapies and New Biomarkers in Cancer research group at the Instituto de Investigación del Hospital Universitario La Paz (IdiPAZ) in Madrid.

    • Lorena Diéguez, leader of the Medical Devices research group at the International Iberian Nanotechnology Laboratory (INL) in Braga.

    • Cristina Saura, head of the Breast Unit at the Vall d'Hebron University Hospital and the Breast Cancer Group at the Vall d’Hebron Institute of Oncology (VHIO) in Barcelona.



    • Sergio Alonso, deputy director of La Razón and founder and director of A TU SALUD, the health supplement that this newspaper has published every Sunday for the past 21 years.


    Projects supported by CaixaResearch: