Breast cancer is the second most common cancer worldwide, affecting nearly one in eight women. Accurate cancer staging is essential for determining the patient’s prognosis and for choosing the appropriate treatment. The staging system most often used is the American Joint Committee on Cancer (AJCC) TNM system, where T refers to the size of the tumor, N refers to spread of the primary cancer to nearby lymph nodes, and M refers to the spread of metastasis to distant sites in the body.

In breast cancer, tyrosine kinase-type cell surface receptor HER2-targeted therapies do not achieve a sustained inhibition of oncogenic signaling. Therapy-resistant tumors compensate for HER2 inhibition through several mechanisms, including increased expression of other cell-surface receptors most notably HER3. HER3 remains currently undruggable despite extensive clinical efforts. Durable efficacy of HER2-based therapy regimens requires, therefore, effective inhibition of HER2 and HER3.

At present, breast cancer is more frequently diagnosed in women than in men. According to global cancer statistics, each year more than 1,675,000 women are diagnosed and more than 500,000 of them die. Some subtypes of breast cancer have been described.

Breast cancer is the most common type of malignant tumor in women, accounting for 30% of women’s cancer, while the mortality rate ranks second among women’s cancer. Twenty-five percent of all breast cancer patients are premenopausal patients, and 7% of patients are younger than 40 years old.

Aquatic prokaryotic cyanobacteria (algal blooms) produce cyanotoxins (CTs), significant pollutants in aquatic ecosystems. Direct exposure to high-concentration CTs through inhalation, skin contact, or ingestion of contaminated water can lead to hepatotoxicity and neurotoxicity. However, the effect of exposure to CTs at low concentrations remains unclear.  Given that CTs can cross the blood–brain barrier via organic anion transporting polypeptides (OATPs), we investigated the effect of acute exposure to low concentrations (10 nM and 50 nM) of CTs, namely microcystin-LR (MC-LR), nodularin (NOD), cylindrospermopsin (CYN), and known neurotoxin β-N-methylamino-l-alanine (BMAA) in neuroblastoma SH-SY5Y cells.