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Purpose: Breast cancer is the most prevalent cancer type in Mexico, with male breast cancer accounting for only 1% of all breast cancer cases. A limited number of studies have described the clinical-pathological profiles of males with breast cancer in low- and middle-income countries. This study presents an analysis of patients with breast cancer seen at three different institutions in México., Methods: A retrospective review of the medical records was performed to analyze the clinical and pathological characteristics of 49 men diagnosed with breast cancer and their overall survival., Results: The mean age at diagnosis was 64.65 years. A significant proportion of patients presented at diagnosis with stage IV disease (n = 11, 22.45%), had triple-negative subtype (n = 6, 12.24%), and nuclear grade III (n = 20, 40.8%). Primary endocrine resistance was observed in 10 patients (31.25%). Genetic analysis was performed on 24 patients (48.9%), revealing a germline BRCA pathogenic variant in 8.33%., Conclusion: Our findings described the clinical and pathological profile of breast cancer in a male cohort in Mexico, with a significantly high proportion of advanced disease, triple-negative subtype, nuclear grade III, and endocrine resistance. Further comprehensive studies, including research into somatic mutations, are needed., Competing Interests: Declarations. Competing interests: The authors have not disclosed any competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

lncRNAs are noncoding transcripts with tissue and cancer specificity. Particularly, in breast cancer, lncRNAs exhibit subtype-specific expression; they are particularly upregulated in luminal tumors. However, no gene signature-based laboratory tests have been developed for luminal breast cancer identification or the differential diagnosis of luminal tumors, since no luminal A- or B-specific genes have been identified. Particularly, luminal B patients are of clinical interest, since they have the most variable response to neoadjuvant treatment; thus, it is necessary to develop diagnostic and predictive biomarkers for these patients to optimize treatment decision-making and improve treatment quality. In this study, we analyzed the lncRNA expression profiles of breast cancer cell lines and patient tumor samples from RNA-Seq data to identify an lncRNA signature specific for luminal phenotypes. We identified an lncRNA signature consisting of LINC01016, GATA3-AS1, MAPT-IT1, and DSCAM-AS1 that exhibits luminal subtype-specific expression; among these lncRNAs, GATA3-AS1 is associated with the presence of residual disease (Wilcoxon test, p < 0.05), which is related to neoadjuvant chemotherapy resistance in luminal B breast cancer patients. Furthermore, analysis of GATA3-AS1 expression using RNA in situ hybridization (RNA ISH) demonstrated that this lncRNA is detectable in histological slides. Similar to estrogen receptors and Ki67, both commonly detected biomarkers, GATA3-AS1 proves to be a suitable predictive biomarker for clinical application in breast cancer laboratory tests.

Given their tumor-specific and stage-specific gene expression, long non-coding RNAs (lncRNAs) have demonstrated to be potential molecular biomarkers for diagnosis, prognosis, and treatment response. Particularly, the lncRNAs DSCAM-AS1 and GATA3-AS1 serve as examples of this because of their high subtype-specific expression profile in luminal B-like breast cancer. This makes them candidates to use as molecular biomarkers in clinical practice. However, lncRNA studies in breast cancer are limited in sample size and are restricted to the determination of their biological function, which represents an obstacle for its inclusion as molecular biomarkers of clinical utility. Nevertheless, due to their expression specificity among diseases, such as cancer, and their stability in body fluids, lncRNAs are promising molecular biomarkers that could improve the reliability, sensitivity, and specificity of molecular techniques used in clinical diagnosis. The development of lncRNA-based diagnostics and lncRNA-based therapeutics will be useful in routine medical practice to improve patient clinical management and quality of life.

Although breast conserving surgery is the standard of care for patients with localized breast cancer in high-income countries, little is known about its use in developing countries, where disparities in access to treatment may lead to an increased use of mastectomy. We examined the use of breast conserving surgery at a Mexican cancer center after the implementation of a public insurance program aimed at providing coverage for previously uninsured patients. Between 2006 and 2016, 4519 women received surgical treatment for breast cancer, of which 39% had early-stage disease. The proportion of patients treated with breast conserving surgery increased from 10% in the 2006-2009 period to 33% in the 2013-2016 period, with most of this increase occurring among women with early-stage disease (17-52%). Improving access to care and reducing the financial burden of breast cancer in developing countries may lead to an increased use of breast conserving surgery., Competing Interests: Declaration of competing interest None., (Copyright © 2021. Published by Elsevier Ltd.)