The tumor microenvironment (TME) consists of numerous biologically relevant elements. One of the most important components of the TME is the extracellular matrix (ECM). The compounds of the ECM create a network that provides structural and biochemical support to surrounding cells. The most important substances involved in the regulation of the ECM degradation process are matrix metalloproteinases (MMPs) and their endogenous inhibitors (tissue inhibitors of metalloproteinases, TIMPs). The disruption of the physiological balance between MMP activation and deactivation could lead to progression of various diseases such as cardiovascular disease, cancer, fibrosis arthritis, chronic tissue ulcers, pathologies of the nervous system (such as stroke and Alzheimer’s disease), periodontitis, and atheroma. MMP-TIMP imbalance results in matrix proteolysis associated with various pathological processes such as tumor invasion. The present review discusses the involvement of two MMPs, MMP-2 and MMP-7, in cancer pathogenesis. These two MMPs have been proven in several studies, conducted mostly on adults, to make an important contribution to cancer development and progression. In the current review, several studies that indicate the importance of MMP-TIMP balance determination for the pediatric population are also highlighted. The authors of this review believe that carrying out biochemical and clinical studies focused on metalloproteinases and their inhibitors in tumors in children will be of great relevance for future patient diagnosis, determination of a prognosis, and monitoring of therapy.

In recent years, researchers have been paying special attention to the tumor microenvironment (TME). One of the most important factors contributing to the development and progression of cancer is the destruction of elements of the extracellular matrix (ECM). The most important substances involved in regulating the extracellular matrix degradation process are extracellular matrix metalloproteinases (MMPs) and their inhibitors (TIMPs). In the process of cancer cell migration, chemokines secreted by target tissues, as well as the profile of chemokine receptors presented on cancer cells, play a key role. In the presented work, five components of the TME were selected: MMP-2, MMP-7, TIMP-2, CXCL-9, and CXCL-10. In the years 2018–2021, peripheral blood samples were collected before the start of treatment and then on day 33 of intensive treatment from 31 patients diagnosed with ALL. The results indicate that the levels of MMP-2, MMP-7, and TIMP-2 did not statistically significantly change before and during treatment of ALL patients. The decrease in CXCL-9 and CXCL-10 levels in the patients’ serum on the 33rd day of therapy turned out to be statistically significant. Our study indicates that serum is also a valuable material for the evaluation of these substances. Conclusions: CXCL-9 and CXCL-10 could be used as one of markers for monitoring the response to treatment and a potential marker of ALL recurrence in pediatric patients. The role of MMP-2, MMP-7, and TIMP-2 in the assessment of response to therapy in children with ALL has not been confirmed.

Introduction: Pediatric rhabdomyosarcoma (RMS) is a rare disease, affecting 4.5-6.0 per 1 000 000 children a year. Bladder and/or prostate (B&P) is the primary tumor site in approximately 10% of patients. Initial symptoms of B&P RMS in children may mimic more common, benign conditions such as urinary tract infections (UTIs), functional disorders, and congenital anomalies of the urinary tract. Aim: The study aims to emphasize the role of careful clinical examination and strict following the diagnostic guidelines in early detection of pediatric B&P RMS in primary care and emergency department settings. Case study: We present two male patients aged 2.5 and 3 years with embryonal B&P RMS initially manifesting as atypical and/or recurrent UTI. In both children, proper diagnoses were delayed due to careless physical examination and failure to adhere to the current guidelines for UTI management. Despite symptoms of an atypical and severe course of UTI, no imaging examinations had been performed for several weeks until dramatic deteriorations of patients’ general conditions occurred. Results and discussion: The prolonged diagnostic processes caused unnecessary suffering of both children and significant delay of oncological treatment in one. In the latter patient, bladder preservation was not possible, resulting in decreased quality of life. Conclusions: Due to its rarity, B&P RMS is infrequently included in the differential diagnosis in children with recurrent or atypical UTI. However, thorough physical examination and adherence to the guidelines of UTI management enable timely diagnosis of underlying malignancy. Early diagnosis of B&P RMS leads to a better prognosis, less intensive treatment, and improved quality of life of B&P RMS survivors.