Mismatch repair deficiency and microsatellite instability in urothelial carcinoma: a systematic review and meta-analysis

Background

Mismatch repair deficiency (dMMR) and microsatellite instability-high (MSI-H) occur in a subset of cancers and have been shown to confer sensitivity to immune checkpoint inhibition (ICI); however, there is a lack of prospective data in urothelial carcinoma (UC).

Methods and analysis

We performed a systematic review to estimate the prevalence of dMMR and MSI-H in UC, including survival and clinical outcomes. We searched for studies published up to 26 October 2022 in major scientific databases. We screened 1745 studies and included 110. Meta-analyses were performed if the extracted data were suitable.

Results

The pooled weighted prevalences of dMMR in bladder cancer (BC) and upper tract UC (UTUC) were 2.30% (95% CI 1.12% to 4.65%) and 8.95% (95% CI 6.81% to 11.67%), respectively. The pooled weighted prevalences of MSI-H in BC and UTUC were 2.11% (95% CI 0.82% to 5.31%) and 8.36% (95% CI 5.50% to 12.53%), respectively. Comparing localised versus metastatic disease, the pooled weighted prevalences for MSI-H in BC were 5.26% (95% CI 0.86% to 26.12%) and 0.86% (95% CI 0.59% to 1.25%), respectively; and in UTUC, they were 18.04% (95% CI 13.36% to 23.91%) and 4.96% (95% CI 2.72% to 8.86%), respectively. Cumulatively, the response rate in dMMR/MSI-H metastatic UC treated with an ICI was 22/34 (64.7%) compared with 1/9 (11.1%) with chemotherapy.

Conclusion

Both dMMR and MSI-H occur more frequently in UTUC than in BC. In UC, MSI-H occurs more frequently in localised disease than in metastatic disease. These biomarkers may predict sensitivity to ICI in metastatic UC and resistance to cisplatin-based chemotherapy.

p53 Expression as a Prognostic Factor in Upper Urinary Tract Urothelial Carcinoma: A Systematic Review and Meta-Analysis

Objective: To conduct a meta-analysis examining p53 expression as a potential risk factor in upper urinary tract urothelial carcinoma (UUT-UC) and to systematically review the available data. Methods: A comprehensive literature review was performed from January 1991 to August 2012, using search engines such as PubMed, EMBASE, Cochrane Library and KoreaMed. All retrieved references were manually reviewed, and two authors independently extracted the data. The quality of case-control and cohort studies was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) checklists. Heterogeneity among studies was examined using the Q statistics and Higgins' I2 statistic. Results: Of 302 abstracts of original research studies, nine case-control trials fit our criteria for inclusion in the analysis. Of the nine articles included, four scored ‘low' and five scored ‘modest' in the quality assessment performed according to the SIGN checklists. Analysis of the correlation between different factors and p53 expression in UUT-UC showed that pathologic stage (≥pT3 or <pT3) differed significantly between the p53 and non-p53 groups (OR = 2.720, p < 0.001). Statistically significant correlations were also detected between p53 expression and histologic grade (OR = 4.507, p < 0.001) and female gender (OR = 2.724, p < 0.001). Conclusion: The results of our meta-analysis suggest that p53 expression in UUT-UC was correlated with advanced pathologic stage, high histologic grade and female gender.