Liquid biopsy group is focused on studying the tumour material in biological fluids, mainly blood from breast and prostate cancer patients. There are different tumour materials that can be analysed: circulating tumour cells (CTCs) which cause metastasis, tumoural genetic material ctDNA/ctRNA, extracellular vesicles and other blood components such as platelets.

Our main goal is isolated and molecular characterized both CTCs and tumoral genetic material in the circulatory system to identify prognostic biomarkers of response, resistance and possible therapeutic targets.

Ongoing projects:

• Liquid biopsy for precision oncology.

Precision oncology aims to treat each patient in a personalized way. Currently, it is well known that each tumour is different and characteristic. It is important to obtain as much information as possible from each sample at different times of the disease (before and after treatment) in order to know how the tumour is behaving and if the treatment is effective or not. Within the framework of this project we have developed a CDX (CTC-derived xenograft). Thus, we isolated CTCs from a patient with breast cancer and injected those cells into a mouse. These cells have implanted in the animal and formed a tumour that has allowed us to study it in greater depth at the molecular level. We have identified a set of markers that are expressed in CTCs, which could be related to this tumour type, such as MELK. We published this work in the IJC journal in 2019.

On the other hand, we have studied the CTCs of patients with metastatic breast or prostate cancer before the start of treatment, after the first cycle of treatment and at the time when treatment stopped working (the disease progression). This has allowed us to study hoe therapy affect the CTCs. We have seen that these cells show epithelial characteristics but also other markers that are associated with the ability of migration or proliferation. We have also identified markers capable of predicting the prognosis of patients after a single cycle of therapy. We published these results in the journal Cancers in 2019 (breast) and 2021 (prostate).

• Identification of resistance mechanisms to systemic treatment in Luminal advanced breast cancer:

The luminal subtype is the most common in breast cancer. It is also one of the subtypes with the best prognosis since it has targeted therapy. However, over time the therapy stops working but it is unknown why. We have identified biomarkers throughout liquid biopsy whose presence is associated with response or resistance to the therapy. These data will be published in the coming months.

• New approaches in Liquid Biopsy: study of blood biomarkers with diagnostic utility in breast cancer and its function in the metastatic cascade:

We have studied the protein profile of erythrocytes from patients with metastatic breast cancer compared to healthy donors. We have seen that the presence of cancer modifies the composition and levels of proteins in the erythrocytes of patients. This has helped us to identify one of these proteins as a diagnostic biomarker for metastatic breast cancer. These results have been patented and will be published in the coming months.