Liquid biopsy is classically defined as the detection of biomarkers in bodily fluids. One of these biomarkers can be circulating cell-free DNA (cfDNA) released by healthy or cancer cells during apoptosis. These fragments can be quantified and molecularly characterized by techniques like digital droplet PCR (ddPCR) or next-generation sequencing (NGS). By identifying common genetic and epigenetic alterations associated with specific cancer types, cfDNA or circulating tumor DNA (ctDNA) can serve as robust biomarkers for monitoring tumor initiation and progression. Other biomarkers, such as circulating microRNAs (miRNAs), extracellular vesicles, or circulating tumor cells (CTCs) are also applied in this context. Liquid biopsy has gained attention as a versatile tool for cancer diagnostics, prognosis, therapeutic monitoring, and minimal residual disease (MRD) detection across various malignancies, including hematological cancers like myeloid and lymphoid leukemias. Herein, we present a comprehensive review of liquid biopsy usage in leukemia, with a specific focus on the clinical utility of ctDNA, miRNAs, and exosomes in monitoring treatment response, tracking clonal evolution, and detecting minimal residual disease. Our review emphasizes the translational implications of these tools for improving patient outcomes and outlines current challenges in their integration into clinical practice.

Introduction. Despite increasing application of molecular diagnostic methods for the detection of sexually transmitted infections, the cytological findings in pap smears of patients with pathogens that can be identified only by PCR are not yet well described. The aim of this study was to describe the most common cytological features in cervical pap smears of patients with Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis, Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum detected by multiplex PCR. Methods. Cervical samples for conventional and liquid‐based cytology and for multiplex PCR were collected from women ranging from 23 to 54 years old, who underwent routine screening at a gynecological Unit. Results. Multiplex PCR was positive in 36.2% of the samples: Ureaplasma parvum 14.9%, Chlamydia trachomatis 10.6%, Trichomonas vaginalis 10.6%, Mycoplasma hominis 8.5%, Ureaplasma urealyticum 4.2%, Neisseria gonorrhoeae 2.1%, and Mycoplasma genitalium (0). Multiple pathogens were observed in 12.8% of samples. Microscopic cervicitis (≥10 polymorphonuclear leukocytes/epithelial cell) and normal (predominantly lactobacillary) microbiota were the most frequent findings in the samples in which the pathogens were detected alone or in multiple infections, except for samples with Trichomonas vaginalis in which the coccobacillary microbiota was the most common. In samples with microscopic cervicitis and normal microbiota, those with at least one pathogen identified by multiplex PCR were significantly more frequent than those with no pathogen, 66.6% versus 33.3%. Conclusion. Failure to identify an inflammatory agent in pap smear with intense neutrophil exudate may suggest the presence of Ureaplasma parvum, Ureaplasma urealyticum, Chlamydia trachomatis, or Trichomonas vaginalis. A remark on the intensity of inflammation should be made in the reports of cervical pap smears so that this cytological finding can be correlated with clinical and PCR results.

Osteosarcoma (OS) is the most common primary malignant bone sarcoma among children and adolescents. Treatment is based on neo-adjuvant and adjuvant chemotherapy, using the standard drugs cisplatin, methotrexate, doxorubicin, and ifosfamide (IFO). Due to the high capacity of tumor resistance, the current work aimed to analyze genes related to cycle control and cell differentiation in OS cells sensitive to and with induced resistance to IFO. This was to assess whether the differentiated expression of these genes may affect resistance to the drug IFO used in OS treatment, and thus establish possible biomarkers of disease progression. In this work, the treatment-sensitive OS U2OS lineage was used, and the same lineage was submitted to the process of induction of IFO resistance. These cells were evaluated by MTT, migration and proliferation assays and submitted to gene expression analysis. The results demonstrate that after induction of resistance to IFO, resistant U2OS cells show a more aggressive tumor behavior, with greater capacity for cell migration, proliferation, and invasion compared to sensitive cells. Gene analysis indicates that resistance-induced cells have differentiated expression of the genes EPB41L3, GADD45A, IER3, OXCT1, UBE2L6, UBE2A ALPL, and EFNB2. Our results suggest new perspectives on possible resistance biomarkers, especially the genes EFNB2 and EPB41L3, given that these genes have rarely been studied their expression linked to osteosarcoma. They show how the resistance induction model can be useful for studies on tumor cell behavior.

Breast cancer is a global public health concern and the most common malignancy in women, with a lifetime risk of 12.5%. It is also the most frequently diagnosed cancer, accounting for 11.6% of all cases. This study is aimed at describing the clinical, anatomopathological, and sociodemographic profile of women diagnosed with breast cancer at a public military hospital in Brazil, and evaluating the association between molecular subtypes and the type of treatment received. This was an observational, cross‐sectional, and quantitative study. Data were extracted from the hospital′s electronic medical records (AGHUse platform) in 2022 and 2025, involving a total of 102 women. Most cases were diagnosed at clinical Stage II (49.0%). Regarding molecular classification, the most prevalent subtype was Luminal B (47.1%), followed by Luminal A (18.6%), HER2‐enriched luminal (16.7%), triple negative (12.8%), and HER2‐enriched nonluminal (4.9%). A total of 54.9% of the tumors had histological Grade 2. Most patients (71.6%) did not present metastases, whereas a minority did (28.4%). Treatment decisions were guided by molecular subtypes, with triple negative and HER2‐enriched subtypes more frequently receiving neoadjuvant or palliative treatment and luminal subtypes predominantly treated with adjuvant therapy; no statistically significant association was found between individual molecular subtypes and the overall type of treatment received, which is likely attributable to the limited statistical power resulting from the small sample size within the neoadjuvant subgroup ( n = 36). The total cohort for neoadjuvant analysis consisted of 36 patients, with a global pathological complete response (pCR) rate of 47.2% ( n = 17). Within the residual disease group ( n = 19), qualitative stratification revealed that 73.7% ( n = 14) achieved a partial response (pPR), whereas 26.3% ( n = 5) presented a minimal response. Although the global association between molecular subtypes and pathological response (pCR vs. RD) did not reach statistical significance ( p = 0.2831), a subgroup analysis comparing aggressive phenotypes (triple negative and HER2‐enriched) against luminal phenotypes (Luminal A and B) was evaluated ( p = 0.169; OR = 3.61; 95% CI: 0.86–15.20). Aggressive subtypes demonstrated a clinically higher rate of pCR (59.1% vs. 28.6%), supporting biological aggressiveness as a driver of chemosensitivity in this cohort. These results contribute to clinical decision‐making and a better understanding of the disease profile in women treated in military hospitals. Moreover, it highlights the need for better response prediction markers for pathological response.

Breast cancer remains a major global health burden, indicating the need for less invasive methods and more accurate biomarkers for diagnosis, prognosis, and treatment monitoring. Circulating microRNAs (miRNAs) are promising liquid biopsy biomarkers that can be detected in peripheral blood and may reflect tumor-associated molecular changes. This integrative literature review assessed recent evidence on circulating miRNAs in breast cancer, with emphasis on blood, plasma, and serum samples and their applications in diagnosis, prognosis, and treatment-related monitoring. The search was conducted for original studies published between 2024 and 2026. After screening and eligibility assessment, 44 studies were included. Serum was the most commonly analyzed sample, followed by plasma; RT-qPCR was the dominant detection method. Diagnostic applications were the most frequently reported, with miR-21 and miR-155 among the most consistently investigated biomarkers. Multi-miRNA panels and computational signatures generally showed higher diagnostic performance than individual miRNAs. Circulating miRNAs were also associated with disease stage, metastasis, recurrence, survival, and response to neoadjuvant chemotherapy, endocrine therapy, trastuzumab, and CDK4/6 inhibitors. Nonetheless, despite these promising findings, methodological heterogeneity, small sample sizes, inconsistent normalization strategies, and limited external validation remain barriers to clinical applications. Standardization and prospective multicenter validation are needed to establish clinical utility.