By Ana Espino | Published on October 11, 2025 | 3 min read
Breast cancer is the most common
cancer among women worldwide. It is characterized by marked biological
heterogeneity and often unpredictable evolution. Although advances in
conventional treatments have improved overall survival, advanced and
metastatic forms remain associated with a poor prognosis.
Traditional approaches, especially chemotherapy, are limited by systemic
toxicity, variable efficacy depending on tumor subtype, and the frequent
emergence of resistance.
In this context, targeted
therapies represent a major advancement, as they act on specific
molecular alterations involved in tumor progression. However, their development
and clinical integration still face numerous challenges, including interindividual
variability in response, high cost, specific side effects,
and the lack of robust predictive biomarkers. The purpose of this review is to
provide an overview of recent progress in targeted therapies for breast
cancer, identifying promising therapeutic pathways, their mechanisms
of action, clinical outcomes, and the obstacles that remain
before broader and more personalized clinical application.
Which weapons for which subtypes?
This review is based on several phase
II and III clinical trials, as well as real-world data, concerning
various subpopulations of patients with breast cancer. It assesses the efficacy
of targeted therapies according to identified molecular alterations,
including HER2, hormone receptors, BRCA mutations, and emerging
markers such as Trop-2 or KRAS. The treatments analyzed
include monoclonal antibodies, antibody–drug conjugates (ADCs), enzyme
inhibitors (CDK4/6, PI3K, PARP), and immunotherapies. Results were compared according to
tumor subtype, clinical response, and adverse events, offering a comprehensive
overview of recent advances and current limitations in targeted approaches.
For
HER2-positive breast cancers, monoclonal antibodies, antibody–drug
conjugates, and PI3K pathway inhibitors have transformed
management, leading to significant survival gains and better
disease control.
In hormone
receptor-positive (HR+) cancers resistant to hormone therapy, CDK4/6
inhibitors have markedly prolonged progression-free survival.
PARP inhibitors, indicated for patients carrying BRCA1/2
mutations, exploit the principle of synthetic lethality to induce
selective cancer cell death. Meanwhile, anti–PD-1/PD-L1 immunotherapy,
though still limited to certain subgroups of triple-negative breast cancers,
represents a notable advancement, offering durable responses in some
cases.
In addition, new generations of
ADCs and inhibitors of emerging targets are under development, with encouraging
results in early clinical trials. These approaches could expand therapeutic
options for advanced and refractory forms of the disease.
Conversely, the study emphasizes the
persistence of secondary resistance, the emergence of specific
adverse effects, and the high costs of these treatments—all of which
limit their accessibility and integration into routine clinical
practice.
Toward precision oncology, step by
step
Breast cancer remains the most
common malignancy in women, and advanced forms continue to pose a
therapeutic challenge despite recent progress. Targeted therapies have
improved survival in several subtypes, but their effectiveness is
constrained by resistance mechanisms, financial burden, side
effects, and the absence of reliable biomarkers to guide treatment
selection.
This review sought to summarize
recent advances in targeted treatments by analyzing clinical efficacy, mechanisms
of action, and current challenges. The findings confirm their clinical
value in certain indications (HER2+, HR+, BRCA-mutated), while also showing
that many barriers persist to their broader and more personalized
implementation.
However, the study highlights the
need for further research, including more diverse cohorts, the
development of multi-omic biomarkers, and the integration of predictive
technologies such as artificial intelligence (AI) and liquid
biopsies. A more accurate cost-effectiveness assessment under real-world
conditions is also essential.
Read next: Nano-spies against breast cancer?
About the author – Ana EspinoPhD in Immunology, specialized in Virology
