Purines and purinergic receptors in primary tumors of the central nervous system.

Purine nucleotides and nucleosides play critical roles in various pathological conditions, including tumor cell growth. Adenosine triphosphate (ATP) activates pro-tumor receptors, while adenosine (ADO) is a potent immunosuppressant and modulator of cell growth. This study aims to analyze the purinergic actions of ATP and its metabolites, associated enzymes, and P1 or P2 class receptors in primary central nervous system tumors. Additionally, we sought to correlate the levels of nucleosides and the density of P1, P2X, and P2Y receptors in cells with tumor progression. The results indicate that purinergic signaling depends on the receptor concentration and signaling molecules specific to each cell type, tissue, and tumor histology. The purinergic system may function as either a tumor-promoting agent or an antitumor factor, depending on the microenvironmental conditions and the concentrations of receptors and their respective activators. Notably, ATP emerges as the most significant extracellular signal, capable of being converted into other cellular stimulators pertinent to neoplasms, such as adenosine diphosphate, adenosine monophosphate, adenosine, and inosine. Consequently, a cascade of responses to these stimuli promotes tumor development, cell division, and metastasis. Purine nucleotides in central nervous system tumors are pivotal in cellular responses in glioblastoma multiforme, vestibular schwannoma, medulloblastoma, adenomas, gliomas, meningiomas, and pineal tumors. These findings hold the potential for developing novel therapeutic strategies and aiding in therapeutic management.

Global impact of pandemic by SARS-CoV-2 on breast cancer diagnosis and screening

Introduction: The pandemic related to the new coronavirus is characterized by high rates of contamination, transmissibility, and mortality. The measures of social isolation adopted by the World Health Organization and corroborated by several countries, with a view to avoiding or minimizing the transmission of COVID-19, can lead to the reduction of the capacity of screening and diagnosis of diseases, such as breast cancer. Objective: This study aimed to analyze the diagnostic indexes and mamaria malignancy diagnosis test, such as mammogram, during the COVID-19 pandemic period. Methodology: Systematic review of the literature based on studies found in the PubMed, SciELO, LILACS, and ScienceDirect databases. Results: The six selected articles demonstrate a reduction in the diagnosis of breast cancer during the pandemic, although with discordant rates. Outcomes such as reduced number of mammograms and change in tumor stage were also analyzed. Conclusion: It is essential to maintain care with the screening, diagnosis, and treatment of breast cancer, in order to minimize the damage caused over more than 1 year of COVID-19 pandemic.