Bioconjugates for breast cancer theranostics: improving target selectivity and treatment efficacy

INTRODUCTION: Breast cancer is the most common cancer diagnosed globally, with various levels of heterogeneity. The current treatment strategy for breast cancer includes surgery, chemotherapy, radiation, hormone, targeted, and immunotherapy. These strategies are combined according to the stage, patient factors, and molecular subtype of breast cancer to enhance survival and diminish the recurrence of cases. Several adverse effects and challenges are associated with these therapies, which render the patient uncomfortable and non-compliant. AREAS COVERED: Bioconjugate-based therapy is one of the advanced therapies emerging to diagnose and treat breast cancer, in which conjugation is done between various molecules, such as monoclonal antibodies and cytotoxic drugs, radionuclides, enzymes, polymers, ligands, and nanoparticles, using linkers. This review aims to critically discuss bioconjugate's recent research advancements in breast cancer theranostics, highlighting their strengths and gaps toward clinical translation, along with patents and clinical trials. PubMed, Scopus, and Google Scholar were used to search the literature in the last five years (2021 to present). EXPERT OPINION: The outcomes of the findings are promising; however, more studies need to be done to establish the mechanistic pathway, long-term toxicity, safety, efficacy, and stability of the bioconjugates for breast cancer to move toward clinical settings.