Understanding and overcoming resistance to immunotherapy in genitourinary cancers.

The introduction of novel immunotherapies has significantly transformed the treatment landscape of genitourinary (GU) cancers, even becoming the standard of care in some settings. One such type of immunotherapy, immune checkpoint inhibitors (ICIs) like nivolumab, ipilimumab, pembrolizumab, and atezolizumab play a pivotal role by disturbing signaling pathways that limit the immune system's ability to fight tumor cells. Despite the profound impact of these treatments, not all tumors are responsive. Recent research efforts have been focused on understanding how cancer cells manage to evade the immune response and identifying the possible mechanisms behind resistance to immunotherapy. In response, ICIs are being combined with other treatments to reduce resistance and attack cancer cells through multiple cellular pathways. Additionally, novel, targeted strategies are currently being investigated to develop innovative methods of overcoming resistance and treatment failure. This article presents a comprehensive overview of the mechanisms of immunotherapy resistance in GU cancers as currently described in the literature. It explores studies that have identified genetic markers, cytokines, and proteins that may predict resistance or response to immunotherapy. Additionally, we review current efforts to overcome this resistance, which include combination ICIs and sequential therapies, novel insights into the host immune profile, and new targeted therapies. Various approaches that combine immunotherapy with chemotherapy, targeted therapy, vaccines, and radiation have been studied in an effort to more effectively overcome resistance to immunotherapy. While each of these combination therapies has shown some efficacy in clinical trials, a deeper understanding of the immune system's role underscores the potential of novel targeted therapies as a particularly promising area of current research. Currently, several targeted agents are in development, along with the identification of key immune mediators involved in immunotherapy resistance. Further research is necessary to identify predictors of response.

Immunotherapy has transformed the treatment landscape for many cancer types, including genitourinary malignancies such as renal and bladder cancers.However, not all patients or tumor types, such as prostate cancer, respond to this type of treatment.Understanding the mechanisms of immunotherapy resistance is critical for developing strategies to overcome these challenges.Primary resistance, which is present at the onset of treatment, can bedue to genetic abnormalities or immune system dysregulation. These factors alter the interactions between host cells and cancer cells.Adaptive resistance develops during therapy due to dynamic changes in the levels of growth factors, cytokines, and the tumor microenvironment (TME).Acquired resistance mainly occurs at the genetic and translational levels, involving the downregulation of critical human leukocyte antigen (HLA) molecules and interference with mutational repair.Future therapies may focus on detailed genetic profiling of patients to guide treatment selection and on the use of immune profile monitoring to assist in assessing responsiveness, alongside developing novel targeted therapies and ICIs.Further research is needed to identify predictors of response to ICIs.

Endoscopic and histological characteristics of small bowel tumors diagnosed by double-balloon enteroscopy.

BACKGROUND/AIMS: Double-balloon enteroscopy (DBE) allows for the diagnoses and treatment of small bowel tumors (SBTs). This study aimed to evaluate the utility of DBE for the diagnosis and treatment of SBTs. METHODS: Patients diagnosed with SBTs who underwent DBE were included in this study. According to their endoscopic appearances, they were categorized as polyps or masses, and according to their histological characteristics, they were categorized as benign or malignant SBTs. RESULTS: A total of 704 patients were retrospectively analyzed, and 90 (12.8%) were diagnosed with SBTs. According to their endoscopic appearance, 48 (53.3%) had polyps and 42 (46.7%) had masses. Additionally, 53 (58.9%) and 37 (41.1%) patients had malignant and benign SBTs, respectively, depending on their histological characteristics. Patients diagnosed with polyps were younger than those diagnosed with masses (p<0.001). Patients diagnosed with benign SBTs were younger than those diagnosed with malignant SBT (p<0.001). Overall, histological diagnosis was determined using DBE in 73 (81.1%) patients. CONCLUSION: DBE is a useful method for diagnosing SBTs. Additionally, the histological type of the lesion can be determined using DBE.