Frequency and Prognostic Value of PTEN Loss in Patients with Upper Tract Urothelial Carcinoma Treated with Radical Nephroureterectomy

Lymph Node Dissection in Upper Tract Urothelial Carcinoma: Current Status and Future Perspectives

PURPOSE OF REVIEW

This narrative review aims to evaluate the role of lymph node dissection (LND) in upper tract urothelial carcinoma (UTUC) and its implications for staging and management outcomes, as well as future perspectives.

RECENT FINDINGS

Multiple studies have demonstrated the limitations of conventional imaging techniques in accurately localizing lymph node metastasis (LNM) in UTUC. While 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18FDG-PET/CT) shows promise for preoperative LNM detection, its specificity is low. Alternative methods such as choline PET/CT and sentinel lymph node detection are under consideration but require further investigation. Additionally, various preoperative factors associated with LNM hold potential for predicting nodal involvement, thereby improving nodal staging and oncologic outcomes of LND. Several surgical approaches, including segmental ureterectomy and robot-assisted nephroureterectomy, provide a possibility for LND, while minimizing morbidity. LND remains the primary nodal staging tool for UTUC, but its therapeutic benefit is still uncertain. Advances in imaging techniques and preoperative risk assessment show promise in improving LNM detection. Further research and multi-center studies are needed to comprehensively assess the advantages and limitations of LND in UTUC, as well as the long-term outcomes of alternative staging and treatment strategies.

Sustained complete response to first-line immunochemotherapy for highly aggressive TP53/MDM2-mutated upper tract urothelial carcinoma with ERBB2 mutations, luminal immune-infiltrated contexture, and non-mesenchymal state: a case report and literature review

Background

Upper tract urothelial carcinoma (UTUC) is a rare malignancy. The management of metastatic or unresectable UTUC is mainly based on evidence extrapolated from histologically homologous bladder cancer, including platinum-based chemotherapy and immune checkpoint inhibitor alone, whereas UTUC exhibits more invasiveness, worse prognosis, and comparatively inferior response to treatments. First-line immunochemotherapy regimens have been attempted in clinical trials for unselected naïve-treated cases, but their efficacies relative to standard chemo- or immuno-monotherapy still remain controversial. Here, we present a case of highly aggressive UTUC for whom comprehensive genetic and phenotypic signatures predicted sustained complete response to first-line immunochemotherapy.

Case presentation

A 50-year-old man received retroperitoneoscopic nephroureterectomy and regional lymphadenectomy for high-risk locally advanced UTUC. Postoperatively, he developed rapid progression of residual unresectable metastatic lymph nodes. Pathologic analysis and next-generation sequencing classified the tumor as highly aggressive TP53/MDM2-mutated subtype with features more than expression of programmed death ligand-1, including ERBB2 mutations, luminal immune-infiltrated contexture, and non-mesenchymal state. Immunochemotherapy combining gemcitabine, carboplatin, and off-label programmed death-1 inhibitor sintilimab was initiated, and sintilimab monotherapy was maintained up to 1 year. Retroperitoneal lymphatic metastases gradually regressed to complete response. Blood-based analyses were performed longitudinally for serum tumor markers, inflammatory parameters, peripheral immune cells, and circulating tumor DNA (ctDNA) profiling. The ctDNA kinetics of tumor mutation burden and mean variant allele frequency accurately predicted postoperative progression and sustained response to the following immunochemotherapy, which were mirrored by dynamic changes in abundances of ctDNA mutations from UTUC-typical variant genes. The patient remained free of recurrence or metastasis as of this publishing, over 2 years after the initial surgical treatment.

Conclusion

Immunochemotherapy may be a promising first-line option for advanced or metastatic UTUC selected with specific genomic or phenotypic signatures, and blood-based analyses incorporating ctDNA profiling provide precise longitudinal monitoring.

Low PTEN expression and overexpression of phosphorylated AktSer473 and AktThr308 are associated with poor overall survival in upper tract urothelial carcinoma

The PI3K/Akt signaling pathway serves an essential role in various cellular processes, including cell growth, survival, cell motility, angiogenesis and cell metabolism. Loss of PTEN expression and hyperactivation of Akt can result in tumorigenesis. Previous studies observed expression of the Akt protein and absence of the PTEN protein in bladder cancer and non-small cell lung carcinoma tissues. The aim of the present study was to evaluate the expression status and prognostic value of PTEN and the PI3K/Akt signaling pathway in Taiwanese patients with upper tract urothelial carcinoma (UTUC). Archival formalin-fixed, paraffin-embedded (FFPE) tissues from 65 UTUC cases were stained via immunohistochemistry for PTEN, phosphorylated (p)Akt serine (Ser)⁴⁷³ and pAkt threonine (Thr)³⁰⁸. The expression levels of each protein were significantly correlated with clinicopathological parameters. PTEN, pAkt^Ser473 and pAkt^Thr308 protein expression levels were higher in adjacent normal tissues compared with those in tumor tissues. Cytoplasmic PTEN protein expression levels were lower in high-stage tumors compared with those in low-stage tumors, and nuclear and cytoplasmic pAkt^Thr308 protein expression levels were higher in high-grade tumors compared with those in low-grade tumors. Univariate analysis showed that high pathological tumor stage (pT2-4) [P=0.01; hazard ratio (HR)=3.40; 95% confidence interval (CI), 1.34-8.60], metastatic status (P=0.003; HR=3.55, 95% CI, 1.55-8.11), low cytoplasmic PTEN protein expression levels (P=0.016; HR=3.14; 95% CI, 1.24-7.95) and high cytoplasmic pAkt^Ser473 protein expression levels (P=0.019, HR=2.71, 95% CI, 1.18-6.21) were predictive of poor overall survival. However, only metastatic status (P=0.031; HR=2.73; 95% CI, 1.10-6.78), low cytoplasmic PTEN protein expression levels (P=0.017; HR=3.29; 95% CI, 1.24-8.73) and high cytoplasmic pAkt^Ser473 protein expression levels (P=0.027; HR=2.64; 95% CI, 1.12-6.23) remained significant in the multivariate analysis. Kaplan-Meier survival analysis showed that high T stage, metastasis, low expression levels of cytoplasmic PTEN protein and high expression levels of cytoplasmic pAkt^Ser473 protein were significantly associated with poor survival (P=0.006, 0.001, 0.011 and 0.014, respectively). Co-expression of PTEN^low/pAkt^Ser473/high and pAkt^Thr308/high phenotypes was associated with a less favorable overall survival (P=0.001). Overall, the present findings demonstrated that low expression levels of PTEN and high expression levels of pAkt^Ser473 and pAkt^Thr308 were predictors for poor overall survival in patients with UTUC.

Precise Immunodetection of PTEN Protein in Human Neoplasia

PTEN is a major tumor-suppressor protein whose expression and biological activity are frequently diminished in sporadic or inherited cancers. PTEN gene deletion or loss-of-function mutations favor tumor cell growth and are commonly found in clinical practice. In addition, diminished PTEN protein expression is also frequently observed in tumor samples from cancer patients in the absence of PTEN gene alterations. This makes PTEN protein levels a potential biomarker parameter in clinical oncology, which can guide therapeutic decisions. The specific detection of PTEN protein can be achieved by using highly defined anti-PTEN monoclonal antibodies (mAbs), characterized with precision in terms of sensitivity for the detection technique, specificity for PTEN binding, and constraints of epitope recognition. This is especially relevant taking into consideration that PTEN is highly targeted by mutations and posttranslational modifications, and different PTEN protein isoforms exist. The precise characterization of anti-PTEN mAb reactivity is an important step in the validation of these reagents as diagnostic and prognostic tools in clinical oncology, including their routine use in analytical immunohistochemistry (IHC). Here, we review the current status on the use of well-defined anti-PTEN mAbs for PTEN immunodetection in the clinical context and discuss their potential usefulness and limitations for a more precise cancer diagnosis and patient benefit.

Circular RNA circC3P1 restrains kidney cancer cell activity by regulating miR-21/PTEN axis and inactivating PI3K/AKT and NF- kB pathways

Kidney cancer (KC) seriously impacts public health. We detected the function and mechanism of circular RNA C3P1 (circC3P1) in KC cells. CCK-8, flow cytometry, migration, and invasion assay were respectively used to investigate the efficacies of circC3P1 and microRNA (miR)-21 on cell viability, apoptosis, migration, and invasion. Phosphatase and tensin homologue deleted on chromosome 10 (PTEN), circC3P1, and miR-21 expression were changed by cell transfection and detected by quantitative reverse-transcription polymerase chain reaction. Moreover, the apoptosis/pathways-related proteins and proteins were detected by western blot analysis. Besides, the relation between PTEN and miR-21 was detected by luciferase assay. circC3P1 and PTEN were downregulated while miR-21 was upregulated in KC tissues. circC3P1 declined cell viability, migration, and invasion and caused apoptosis. Furthermore, circC3P1 negatively regulated miR-21; miR-21 mimic could reverse the efficacies of circC3P1. Besides, circC3P1 restrained the PI3K/AKT and NF-κB pathways by downregulating miR-21. Finally, PTEN was authenticated as a target of miR-21. circC3P1 restrained KC cell growth, migration, and invasion by regulating miR-21/PTEN axis and inactivating PI3K/AKT and NF-κB signaling pathways.