Sequencing mutations in selected genes form circulating tumor cells (metastatic breast cancer)

The study goal is to evaluate genetic heterogeneity of circulating tumor cells (CTC) isolated from the blood of patients with metastatic breast cancer. Single CTCs were isolated using EpCAM-independent system Cytotrack, which allows detection and subsequent isolation of tumor cells from the blood sample. Single cells isolated using Cytopicker (a micromanipulator) were subjected to whole genome amplification, followed by genetic analysis with next generation sequencing. The analysis included sequencing of the hotspot regions in three genes: ESR1, AKT1 and PIK3CA and the whole exome in four genes: TP53, AKT2, ESR2 and GATA3. Detection of genetic changes in ESR1 and ESR2 can contribute to the prediction of endocrine resistance. Furthermore, PI3K / AKT / mTOR signaling is interdependent and entwined with ER signaling and acquired endocrine resistance. Frequent mutations in ESR1, PIK3CA, and AKT1 have been identified in BC patients and are implicated as drivers of resistance and recurrence of the disease. Mutations in these genes and the resulting variations of resistance to hormonal therapy are important for proper diagnosis and treatment decisions. It is a known fact that genetic makeup of metastatic lesions can be different to that of the primary tumor. In metastatic patients performing a biopsy of a metastatic lesion to assess these genetic changes is invasive, not completely reliable, and can be difficult. In patients with mBC, liquid biopsy (CTC analysis) can be a proxy for metastatic lesion biopsy and serve as a monitoring system for changes in ER status. This project aim to evaluate the feasibility and clinical value of monitoring genetic changes in isolated CTCs.