Recent advances in microfluidic chip technologies for applications as preclinical testing devices for the diagnosis and treatment of triple-negative breast cancers

The leading cause of cancer-related death among female patients is breast cancer. Among all the types of breast cancer, triple-negative breast cancer (TNBC) is the most dangerous molecular subtype of breast cancer characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2) expression. Since there is no particular therapeutic strategy for TNBC that has been shown to worsen the disease prognosis, 3D models are superior to 2D models as a predictive tool for drug discovery because they more accurately reflect the in vivo biological components of humans. Importantly, all 3D models struggle to gather many high-quality tumour cells from clinical tumours. Physicians may not get huge tumour tissues from patients, and clinical tumours may have necrosis, fat, and blood vessel components. Therefore, there is an immediate need to find an efficient method to consistently and quickly produce a large number of homogeneous tumour models for individual treatment without cell wastage. Microfluidic technologies, which are specifically engineered to manipulate small quantities of fluids, have been utilised to produce particles for drug delivery applications. This development is indicative of a recent trend, as it provides the ability to regulate particle size and material composition. This review focuses on the topic of tumor-on-a-chip, microfluidic chip manufacturing, and drug screening for triple-negative breast cancer. Particular emphasis is placed on cancer biomarker diagnostics, 3D preclinical model development, and treatment strategies for triple-negative breast cancer.