Study maps HER2 mutations in lung cancer patients from Northeastern Brazil

A new research paper was published in Volume 16 of Oncotarget on June 17, 2025, titled "Molecular landscape of HER2-mutated non-small cell lung cancer in Northeastern Brazil: Clinical, histopathological, and genomic insights."

In this study, researchers led by first authors Cleto Dantas Nogueira from the Federal University of Ceará and Argos Pathology Laboratory and Samuel Frota from Argos Pathology Laboratory, along with corresponding author Fabio Tavora from the previously mentioned institutions and Messejana Heart and Lung Hospital, investigated how HER2 gene mutations appear in cases of non-small cell lung cancer (NSCLC) in Northeastern Brazil. The team found that HER2 mutations showed significant genetic diversity and were often associated with other cancer-related genetic changes. These findings revealed diagnostic and treatment challenges in a population that is rarely studied, emphasizing the need for expanded access to molecular testing and targeted therapies.

HER2 mutations are a known factor in several cancers, including breast and gastric cancers. In lung cancer-particularly NSCLC-these mutations are less common but remain clinically significant. Most existing research on HER2-mutated lung cancer focuses on high-income countries, leaving important gaps in knowledge about underrepresented regions such as Latin America. This study helps fill that gap by analyzing 13 patients with HER2-mutated NSCLC using clinical, pathological, and genomic data.

The patients ranged in age from 34 to 82 years, and more than half were women. About half had never smoked. Their tumors often displayed complex genetic profiles, including additional mutations in genes such as TP53, KRAS, and STK11. The most common HER2 mutation identified was an insertion in exon 20, a known hotspot for activating mutations.

"Trastuzumab deruxtecan (T-DXd) is the first HER2-targeted agent to show clinical efficacy in HER2-mutant non-small cell lung cancer (HER2m NSCLC)."

Treatment strategies among the patients varied. Only one individual received HER2-targeted therapy. Most were treated with surgery, chemotherapy, immunotherapy, or a combination of these approaches. Outcomes also differed, with some patients surviving for years and others dying within months of diagnosis. These findings reinforce the need for early diagnosis and improved access to advanced treatments, particularly in low-resource settings.

The study emphasizes the value of comprehensive molecular profiling in NSCLC. Because HER2 mutations often occur alongside other genetic alterations, full genomic analysis is crucial for guiding treatment decisions. Yet, such testing is not always available. The researchers propose a tiered diagnostic approach, beginning with basic screening and expanding to more advanced tests when necessary, to enhance patient care.

This study provides valuable insights into the molecular characteristics of HER2-mutated NSCLC in a Brazilian population, highlighting the complexity and clinical relevance of these alterations. Larger studies are needed to clarify the prevalence and prognostic significance of HER2 mutations, as well as their impact on treatment response and survival. This knowledge is essential for advancing effective HER2-targeted therapies. The findings also support broader implementation of international clinical guidelines in Latin America and highlight the critical need to include underrepresented populations in cancer research.