Circulating Tumor Cells and Breast Cancer Metastasis: From Enumeration to Somatic Mutational Profile

Area of Science:

• Oncology
• Molecular Biology
• Cancer Metastasis Research

Background:

• Circulating tumor cells (CTCs) are shed from primary tumors into the bloodstream.
• Understanding the role of CTCs in breast cancer metastasis is crucial for prognosis and treatment.
• Previous studies have explored CTCs, but specific associations with organ metastasis require further investigation.

Purpose of the Study:

• To investigate the association between circulating tumor cell (CTC) enumeration and breast cancer metastasis.
• To identify specific organ tropisms for CTC-associated metastasis.
• To characterize the mutational landscape of CTCs in patients with brain metastasis.

Main Methods:

• Retrospective analysis of 116 breast cancer patients.
• Utilized adjusted logistic regression and random forest algorithms for association studies.
• Performed next-generation sequencing (NGS) on CTCs from two patients with brain metastasis.

Main Results:

• Patients with CTC counts ≥ 5 had a significantly higher risk of overall tumor metastasis (OR = 6.25).
• Elevated CTC levels were strongly associated with liver metastasis (OR = 4.87).
• NGS identified 120 indel mutations in CTCs, implicating pathways like focal adhesion and PI3K-Akt signaling.

Conclusions:

• Circulating tumor cell counts ≥ 5 are a significant risk factor for breast cancer metastasis.
• High CTC levels are particularly linked to an increased risk of liver metastasis.
• NGS provides insights into the genetic alterations within CTCs, relevant to metastatic processes.